JPH08107144A - Method for manufacturing semiconductor device - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A semiconductor device including a step of cleaning the surface of an insulating film or a conductive film, and a method for manufacturing the same, in which the surface of the insulating film is cleaned to prevent degassing of the insulating film. At the same time, improve selective growth in the opening of the interlayer insulating film. A step of forming an insulating film 6 on a substrate 1 and exposing the insulating film 6 to chlorine fluoride plasma to terminate at least the surface of the insulating film 6 with fluorine to improve water permeation resistance. Including steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a semiconductor device including a step of cleaning the surface of an insulating film or a conductive film and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device, a multi-layer wiring structure has been adopted as the density becomes higher. In the multilayer wiring structure, an interlayer insulating film is interposed between the upper and lower wirings, and the upper and lower wirings are connected to each other through the opening of the interlayer insulating film. As a method of filling the conductive material in the opening, there is a method of simultaneously filling the wiring material in the opening when forming the upper wiring, or a method of selectively growing a metal in the opening.

As a matter of course, when tungsten is selectively grown in the opening, it is required not to grow on the surface of the interlayer insulating film. However, in reality, there are many cases where carbon, hydroxide, or the like, which becomes a growth nucleus of tungsten, exists on the surface of the interlayer insulating film. Therefore, when the interlayer insulating film is formed of a silicon oxide film (SiO ₂ ), a method of slightly etching the surface of the interlayer insulating film with hydrofluoric acid to simultaneously remove growth nuclei on the surface is generally adopted. There is.

However, the use of hydrofluoric acid is not sufficient to prevent the growth on the interlayer insulating film. For example, if tungsten is selectively grown in the opening over time, in the worst case, tungsten may grow in blanket form (overall growth) on the interlayer insulating film. Moreover, since the hydrofluoric acid laterally etches the opening, the diameter of the opening is widened.

Therefore, in order to improve the selective growth of tungsten, various other proposals have been made. For example, after forming a titanium nitride (TiN) film on the diffusion layer of the silicon substrate exposed from the opening of the interlayer insulating film and on the interlayer insulating film, TiN is mixed with a mixed solution of sulfuric acid and hydrogen peroxide solution. JP-A-4-130720 describes that thin TiN on the surface of the diffusion layer is removed, and then tungsten is selectively grown on titanium silicide (TiSi) existing on the surface of the diffusion layer. In this case, on the interlayer insulation film
It is premised that the growth of tungsten starts late in the TiN film.

However, in the literature [1] cited in that publication as a proof, tungsten hexafluoride gas is supplied to the surface of the underlying TiN film before forming tungsten by silane (SiH ₄ ) reduction. The selective growth of tungsten is described by comparing the case where it is supplied and the case where it is not supplied, and there is no description about the comparison between the TiSi film and the TiN film which are the underlayer of the selective growth. actually,
It is not clear how much the difference in the start time of tungsten growth between the TiN film and the TiSi film.

Reference [1]: Proceedings of the 36th Congress of Applied Physics, 1989, pp. 2718, 3a-ZF-2 Note that sulfuric acid and hydrogen peroxide solution used as etching solution for TiN film The mixed solution may be used as a cleaning solution after removing the resist, but since the mixed solution is an oxidant and may oxidize the metal surface, it is generally used as a surface treatment of the film. It was never used.

On the other hand, various methods have been proposed for facilitating selective growth of tungsten by cleaning the surface of the silicon layer or aluminum layer exposed from the opening of the interlayer insulating film by dry treatment. For example, an oxide film existing on the diffusion layer of the silicon substrate exposed from the opening of the SiO ₂ interlayer insulating film,
After removing the polymer etc. with chlorine trifluoride gas,
Methods for selectively growing tungsten in the opening are described in JP-A-64-73717 and JP-A-5-243218.

Further, after removing the natural oxide film on the surface of the aluminum wiring exposed from the opening of the SiO ₂ interlayer insulating film by using chlorine trifluoride gas, tungsten can be selectively grown in the opening. -206526.

[0010]

By the way, as the interlayer insulating film, not only SiO ₂ but also an SOG (spin on glass) film formed by a spinner or a silicon oxide film formed by using TEOS is used. As a result, selective growth of tungsten has become difficult due to the gas released from such an interlayer insulating film.

In order to remove gas from such an interlayer insulating film, a method of heating the insulating film may be adopted, but the degassing effect is temporary and does not deteriorate hygroscopicity. . For example, if the interlayer insulating film is heated and then left to stand in an environment such as a hydrofluoric acid solution, an etching solution, or the atmosphere, the interlayer insulating film absorbs moisture, and there is a problem that degassing treatment becomes necessary again.

Further, as the lower conductive pattern exposed from the opening of the interlayer insulating film, not only the diffusion layer of the silicon substrate and the aluminum wiring but also the conductive pattern of refractory metal, copper, gold or the like is used. There is also. In this case, it is conceivable to use dilute hydrofluoric acid to clean the surface of the conductive pattern, but as described above, the silicon oxide-based interlayer insulating film is also etched, which causes the disadvantage that the opening is widened. .

The present invention has been made in view of the above problems, and cleans the surface of the insulating film to prevent outgassing from the insulating film and improves selective growth in the opening of the interlayer insulating film. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can be manufactured.

[0014]

The above-mentioned problems can be solved by forming the insulating film 6 on the substrate 1 and exposing the insulating film 6 to chlorine fluoride plasma, as shown in FIG. This is achieved by a method of manufacturing a semiconductor device, which comprises a step of cleaning the surface of the insulating film 6 and a step of simultaneously terminating at least the surface of the insulating film 6 with fluorine to improve water permeation resistance.

Alternatively, an opening 6a is formed in the insulating film 6, and the insulating film 6 and the conductive layer 4 are formed with a part of the conductive layer 4 under the insulating film 6 exposed from the opening 6a. Is exposed to the chlorine fluoride plasma, and then selectively growing the metal 7 on the surface of the conductive layer 4 under the opening 6a is achieved by the method for manufacturing a semiconductor device.

Alternatively, after the step of exposing the insulating film in which the opening 6a is formed to the chlorine fluoride plasma, the insulating film 6 is once exposed to the atmosphere, or is not exposed to the atmosphere and the selective growth of the metal 7 is performed. This is achieved by the method for manufacturing a semiconductor device described above. Alternatively, the temperature of the substrate 1 when exposing the insulating film 6 and the conductive layer 4 under the opening to the chlorine fluoride plasma is 150 ° C. or lower, which is achieved by the method for manufacturing a semiconductor device. .

Alternatively, when the insulating film 6 is exposed to the chlorine fluoride plasma, only the surface of the conductive layer 4 under the opening 6a is selectively etched, which is a method of manufacturing the semiconductor device. To achieve by. Alternatively, when the insulating film 6 is exposed to the chlorine fluoride plasma, the substrate 1 is placed under a pressure of 10 Torr or less, which is a method for manufacturing a semiconductor device.

Alternatively, it is achieved by a method of manufacturing a semiconductor device characterized in that the power for generating the chlorine fluoride plasma is 50 W or less. Alternatively, the substance forming the conductive layer 4 has a lower activation energy of chemisorption than the constituent material of the insulating film 6, which is achieved by the method for manufacturing a semiconductor device.

Alternatively, the gas used for generating the chlorine fluoride plasma is any one of chlorine fluoride, chlorine trifluoride, and chlorine pentafluoride. To achieve by. Alternatively, the chlorine fluoride, chlorine trifluoride, and chlorine pentafluoride are diluted with helium, neon, argon, xenon, kropton, and nitrogen, thereby achieving the semiconductor device manufacturing method.

Alternatively, it is achieved by the method for manufacturing a semiconductor device, wherein the chlorine fluoride, the chlorine trifluoride, and the chlorine pentafluoride are plasmatized without being diluted. Alternatively, the insulating film 6 may be SOG, PSG, B
This is achieved by a method of manufacturing a semiconductor device, which is a silicon oxide film formed using PSG, NSG, SiN, SiON, or an organic source gas.

Alternatively, as illustrated in FIG. 15, a step of forming an insulating film 9 and an opening 9a are formed in the insulating film 9 to expose a part of the metal layer 4 under the insulating film 9. A step of immersing the insulating film 9 and the conductive layer 4 in a mixed solution of sulfuric acid and hydrogen peroxide, and selectively groWing the metal 10 in the opening 9a after the immersion. And a method of manufacturing a semiconductor device.

Alternatively, the hydrogen peroxide in the mixed solution is 50% or less, which is achieved by the method for manufacturing a semiconductor device. Alternatively, the mixed solution is 20 to
This is achieved by the method for manufacturing a semiconductor device, which is characterized in that the temperature is maintained at 200 ° C. Alternatively, the method for manufacturing a semiconductor device is characterized in that the insulating film 9 and the conductive layer 4 are immersed in the mixed solution for 30 minutes or less.

Alternatively, the metal 7 is a refractory metal, which is achieved by the above-described method for manufacturing a semiconductor device.

[0024]

[Operation] According to the present invention, the insulating film covering the wiring is exposed to chlorine fluoride plasma to clean the surface of the insulating film, and at the same time, at least the surface of the insulating film is subjected to a fluorine termination treatment to prevent water permeation. Has improved. For this reason,
There is no carbon, hydroxide, etc. on the surface of the insulating film, degassing is prevented at the same time, and it is difficult for metal nuclei to grow on the surface of the insulating film when selectively growing metal such as tungsten in the opening of the insulating film. As a result, the selectivity is improved, and the corrosion of the metal wiring formed on the insulating film is prevented.

Further, since chlorine fluoride plasma simultaneously removes the oxide layer on the surface of the conductive layer below the opening of the insulating film, it is possible to selectively grow a metal on the conductive layer in the opening. The growth rate on the conductive layer is increased and the selectivity is improved. The number of metal nuclei that grow on the surface of the insulating film during the selective growth of the metal in the opening can be determined even if the insulating film exposed to chlorine fluoride plasma is placed in the atmosphere without being placed in the atmosphere. Even if it is continuously performed under reduced pressure, it does not change and maintains good selective growth. This is due to the effect of water permeation resistance.

The substrate temperature is important because it does not overetch the conductive layer below the opening, and the substrate temperature is 1
It is 50 ° C or lower. In order to prevent damage to the insulating film and excessive etching of the conductive layer, the pressure of chlorine fluoride plasma needs to be 10 Torr or less. Further, in order to prevent excessive etching of the conductive layer and damage to the insulating film, it is necessary to set the power for generating plasma to 50 W or less.

For insulation that is easily degassed, SOG (spin
on glass), PSG (phospho-silicate glass), BPS
G (boro-phospho silicate glass), NSG (non-dope
silicate glass) or silicon oxide formed using organic gas. Gases used to generate chlorine fluoride plasma include chlorine fluoride, chlorine trifluoride, and chlorine pentafluoride, which do not need to be diluted, but when you want to reduce the effect a little. Helium,
It may be diluted with neon, argon, xenon, kropton, nitrogen.

According to another aspect of the invention, the insulating film and the conductive layer exposed from the opening are immersed in a mixed solution of sulfuric acid and hydrogen peroxide to clean their surfaces. It has been found that sulfuric acid and hydrogen peroxide do not function as oxidants for the conductive layer (metal). In order to obtain a stable reaction, hydrogen peroxide in the mixed solution is 50% or less, and the mixed solution is 20 to 20%.
The temperature is set to 0 ° C. Further, by setting the treatment time to within 30 minutes, excessive etching of the conductive layer can be prevented.

The metal selectively formed in the opening is a refractory metal such as tungsten or molybdenum.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 are sectional views showing steps from the formation of an opening in an insulating film of a semiconductor device to the selective growth of tungsten in the opening.

First, as shown in FIG. 1A, a SiO ₂ film (insulating film) 2 having a thickness of 3000 Å is formed on the surface of a silicon substrate 1, and a titanium nitride (TiN) layer 3 is further formed thereon. 10
A 00Å and tungsten (W) layer 4 is formed to a thickness of 3000Å. The TiN layer 3 and the W layer 4 are patterned to be lower wiring. Further, the W layer 4 is covered with a 5000 Å SiO ₂ film 5 formed by CVD, and an SOG film 6 is formed on the SiO ₂ film 5 to a thickness of 5000 Å.

The SOG film 6 was formed for flattening.
The SOG film 6 is formed on the SiO ₂ film 5 because the SOG film 6 is formed.
This is because an insulating film having a thickness of 1 μm cannot be formed by itself. The SiO ₂ film 5 and the SOG film 6 form an interlayer insulating film. After that, the SOG film and the SiO ₂ film are patterned by photolithography using a photoresist as a mask to form an opening 6a in these films as shown in FIG. 1 (b).

Next, the silicon substrate 1 is placed between the parallel plate electrodes 11a and 11b in the chamber 10 of the plasma generator as shown in FIG. 3 (a), and ClF ₃ gas of 100 is placed between them.
It is introduced at a flow rate of sccm, and the pressure inside the chamber 10 is reduced to 6.7 Pa (50 mTorr). Then, a high frequency power RF of 13.56 MHz was applied at 10 W between the parallel plate electrodes 11a and 11b, and the temperature of the silicon substrate 1 was set to room temperature (about 25 ° C.). By maintaining this state for 30 seconds, as shown in FIG. 1 (c), the SOG film 6 is exposed to ClF ₃ plasma to improve the quality of the SOG film 6, and at the same time, the tungsten oxide on the surface of the tungsten layer 4 ( WO _X ) 4a was removed.

Next, after stopping the introduction of ClF ₃ , the substrate 1
Is transferred to the separately prepared growth chamber 13 shown in FIG. 3 (b) through the gate valve 12 without being exposed to the atmosphere. Subsequently, the substrate is heated in the growth chamber 13 and tungsten hexafluoride (WF ₆ ), hydrogen (H ₂ ) and monosilane (SiH ₄ ) are introduced to expose it from the openings 6 of the SOG film 6 and the SiO ₂ film 5. Tungsten was selectively grown on the formed W layer 4.

Tungsten was selectively grown on the W layer 4 exposed from the openings 6a of the SOG film 6 and the SiO ₂ film 5. As a result, as shown in FIG. 2, even though the depth of the opening 6a is as deep as 1 μm, the growth of the tungsten film is observed on the SOG film 6 with the opening 6a filled with tungsten. There wasn't. The selectivity collapse on the surface of the SOG film 6, that is, the number of tungsten nuclei grown on the surface of the SOG film 6 was 1/10000 or less of that in the case where the SOG film 6 was not exposed to ClF ₃ plasma. Further, even if the aluminum wiring was formed on the interlayer insulating film, the aluminum wiring was not corroded by the gas discharged from the insulating film.

In this way, the SOG film 6 containing a large amount of water etc.
The reason why tungsten did not grow on the surface was that fluorine was bonded to the bond of the element on the surface of the SOG film 6 as shown in the partially enlarged view of the broken line in FIG. 1 (c). The present inventors attempted the following experiments in order to prevent degassing from an insulating film such as an SOG film, a PSG film, a BPSG film and the like.

First, a plurality of samples as shown in FIG. 4 were prepared. The sample is a SiO ₂ film 22 having a thickness of 3000 Å formed on the surface of a silicon substrate 21 by thermal oxidation, and its Si.
5000 Å SOG film 2 formed on the O ₂ film 22
Three. As shown in FIG. 5, these samples are left in the air for a while, and the sample which is not subjected to any treatment thereafter is used as the first sample, and then SOG is applied to ClF ₃ plasma.
The sample to which the film 23 is exposed is the second sample.

As a device for exposing the SOG film 23 of the second sample to ClF ₃ plasma, the plasma generator shown in FIG. 3 (a) was used. Then, after placing the second sample on the lower parallel plate electrode 11b in the depressurized chamber 10, 100 scF of ClF ₃ gas is introduced from the gas inlet 10a of the chamber 10.
It is introduced at a flow rate of cm and the pressure inside the chamber 10 is 6.7 Pa.
(50 mTorr), and high frequency power of 10 W at 13.56 MHz was applied between the parallel plate electrodes 11a and 11b. As a result, the SOG film 23 of the second sample is removed at room temperature
A second sample was exposed to the atmosphere after being exposed to the ClF ₃ plasma for only a second.

Then, with respect to each of the first and second samples, the degassing amount was examined by using a pressure reducing device as shown in FIG. The amount of degassing is 1
It is determined from the difference between the degree of vacuum inside the chamber 5 and the degree of vacuum inside the decompression chamber 15 when either the first sample or the second sample is stored. The degree of vacuum in the decompression chamber 15 of the decompression device of FIG. 6 is measured by an ionization vacuum gauge 16. The susceptor 17 on which the sample is placed is heated to 150 ° C. The exhaust of the decompression chamber 15 is stopped during the measurement by the ionization vacuum gauge 16.

Pressure in the decompression chamber 15 when no sample is present
2.67 × 10 when the force is measured ^-FourPa (2.00 x 1
0^-6Torr). And while holding that pressure
The first sample was placed in the decompression chamber 15 to measure the degree of vacuum.
The pressure inside the decompression chamber 15 is 4.00 × 10.^-2Pa
(3.00 x 10^-FourTorr), which caused 3.9
7 x 10^-2Pa (2.98 × 10^-FourTorr) degassing amount
I understand that In contrast, the second sample was 2.67.
× 10^-FourPa (2.00 x 10^-6In the decompression chamber 15 of Torr)
When the vacuum degree was measured by placing it, the decompression chamber 15 was found to be 6.6.
7 x 10^-FourPa (5.00 × 10^-6Torr) and degas
Amount is 4.00 × 10^-FourPa (3.00 x 10 ^-6Torr)
I knew it was.

[0041] Thus, it was confirmed that there is a difference of about two orders of magnitude in the degassing amount by the presence or absence of ClF ₃ plasma process, ClF ₃
It was confirmed that it is effective to reduce the amount of degassing of the insulating film by plasma treatment. Next, the surface of the SOG film 23 before and after the ClF ₃ plasma treatment is subjected to ESCA (elec
FIG. 7 shows the result of evaluation by tron spectroscopy for chemical analysis). As a result, silicon elements, oxygen elements, and carbon elements are present in the surface layer of the SOG film 23 before the ClF ₃ plasma treatment, but after the treatment,
It was confirmed that the elemental fluorine was present instead of the significant reduction of the elemental carbon due to the etching effect of ClF ₃ . As a result, it can be seen that the surface of the SOG film 23 is cleaned and the elemental hands on the surface are terminated by the fluorine element. Further, the SOG film 23 that has been subjected to the ClF ₃ plasma treatment has a greatly reduced amount of degassing whether it is exposed to the atmosphere or not. It is considered that this is because fluorine penetrates not only on the surface of the SOG film 23, but also inside the degassed inside thereof to improve the water permeation resistance.

As shown in FIG. 2, the fact that tungsten does not grow selectively on the surface of the SOG film 6 means that chlorine gas plasma treatment not only degass the SOG film 6 but also deposits such as carbon on the surface. Removal is done at the same time, SO
It means that the surface of the G film 6 has a cleaning effect. Next, the improvement in selective growth by using ClF ₃ plasma treatment as a pretreatment for selectively growing tungsten by CVD will be quantified and described.

Using a plurality of samples having the structure shown in FIG. 1 (a), the SOG film 6 was exposed to ClF ₃ plasma, and then transferred to another reaction chamber 13 without breaking the vacuum. Was used in a gas atmosphere of tungsten hexafluoride, hydrogen and monosilane. In this case ClF ₃
The plasma treatment condition is that ClF ₃ gas is introduced at 100 sccm and the pressure in the chamber is 13.3 Pa (100 mTor).
r), substrate temperature is room temperature, parallel plate electrode applied power is 10W
And the occurrence time was variable from 0 to 600 seconds. In addition, as for the selective growth condition of tungsten, WF _{6 is set} to 18
It was introduced into the reaction chamber at a flow rate of sccm, SiH ₄ was 7.2 sccm, hydrogen was 100 sccm, and the pressure in the reaction chamber was 13.3 Pa (100
mTorr), substrate temperature 300 ° C, growth time 0-600
The second was variable.

Then, when the relationship between the exposure time of the SOG film 6 to ClF ₃ plasma and the elemental fluorine concentration on the surface of the SOG film 6 was determined by ion chromatography analysis, the results shown in FIG. 8 were obtained. Is 8 × 10 ¹⁴ mo in 10 seconds
1/10 ¹⁵ mol / cm ^{2 in} l / cm ² and 60 seconds, and thereafter, the fluorine element on the surface of the SOG film gradually rises as the plasma treatment time is lengthened.

Further, the amount of tungsten deposited on the surface of the SOG film 6 by the subsequent treatment under the selective growth condition with respect to the ClF ₃ plasma treatment time was measured by ICP analysis.
The results shown in FIG. 9 were obtained. According to this, it can be seen that the amount of deposited tungsten sharply decreases within 60 seconds from the start, and thereafter, the amount of deposited tungsten gradually decreases.

As described above, since the trends of the curves in FIGS. 8 and 9 almost coincide with each other, the growth of tungsten on the SOG film 6 is hindered by the presence of fluorine, which causes W in the opening 6a. It can be seen that the selective growth property on the film 4 is improved. In addition, when tungsten is selectively grown in the opening 6a without breaking the vacuum after exposing the SOG film 6 to ClF ₃ plasma, and when the SOG film 6 is exposed to ClF ₃ plasma and then exposed to the atmosphere, the tungsten is removed. There was no difference in selective growth from the case of selective growth.

By the way, the power of the high frequency power applied between the parallel plate electrodes during the ClF ₃ plasma treatment is 10 W and 50 W.
When the selective growth property was examined for each of the above cases, a remarkable collapse of the selective growth was observed at 50 W. This is because when a high plasma power is used, a damage layer 6b due to plasma is generated on the surface of the SOG film 6 as shown in FIG. 10, and as a result, a tungsten nucleus 7a grows on the damage layer 6b and the selectivity is increased. It is thought that the collapse occurred. Therefore, in order to prevent the damage layer 6b from being generated, it is necessary to perform the ClF ₃ plasma treatment at a power lower than 50 W, and more preferably 30 W or less.

Although the SOG film is used in the above description, an insulating film from which gas is easily released, such as PSG,
It is particularly effective for BPSG, NSG, SiON, silicon oxide formed using an organic gas source, SiN, SiON, or the like. Moreover, the such a conductive layer formed below the insulating film, molybdenum, a refractory metal such as titanium, and the refractory metal silicide, titanium nitride, aluminum, copper, the ClF ₃ plasma be a gold The surface of the conductive layer is cleaned.

Further, although ClF ₃ plasma is used for the surface treatment of the SOG film in the above example, chlorine fluoride (ClF) and chlorine pentafluoride (Cl) are used as the gas containing fluorine and chlorine.
Either of F ₅ ) may be plasmatized and used. ClF ₃ , ClF ₃ and ClF ₅ may not be diluted, or may be diluted with helium, neon, argon, krypton, xenon, nitrogen or the like. When it is desired to reduce the cleaning effect on the surface of the interlayer insulating film 6 or the etching effect on the metal film thereunder, ClF ₃ , ClF ₃ and ClF ₅ are diluted.

As the metal for selective growth, a refractory metal other than molybdenum, for example, tungsten may be used. When selectively growing molybdenum, molybdenum hexafluoride is used as a reaction gas. (Second Embodiment) In the first embodiment, when a metal is selectively grown in the opening of the interlayer insulating film, the surface of the interlayer insulating film is cleaned and degassed simultaneously, and the lower electrode exposed from the opening is removed. Cleaning the surface has been described.

In this embodiment, when the surface of the interlayer insulating film is cleaned, the interlayer insulating film is prevented from being thinned and the opening is prevented from expanding, and at the same time, the conductive layer below the interlayer insulating film is excessively large. Preventing unnecessary etching will be described.
First, three samples are prepared. The first sample is shown in FIG.
As shown in (a), the silicon wafer 31 is not surface-treated. As shown in FIG. 11 (b), the second sample is a silicon wafer 31 on the surface of which a silicon oxide film (SiO ₂ ) film 32 having a thickness of 3000 Å is formed by thermal oxidation.
Is. As shown in FIG. 11C, the third sample is a titanium nitride (TiN) film formed on the surface of the silicon wafer 31 by sputtering or CVD (chemical vapor deposition) on the SiO ₂ film 32 having a film thickness of 3000 Å. 33 to 1000Å, Tungsten (W)
The film 34 is sequentially formed to have a thickness of 3000 Å.
The TiN film 33 is used to improve the adhesion between the tungsten film 34 and the SiO ₂ film 32.

First, at room temperature, a diluted hydrofluoric acid solution was prepared.
The etching amount of the SiO ₂ film 32 of the _second sample by any of the ClF ₃ plasma treatments was compared. In this case, the diluted hydrofluoric acid used had a hydrofluoric acid concentration of 1%. Further, when ClF ₃ plasma treatment, without the addition of a diluent gas of any way to ClF _3, 100 sccm flow rate of ClF ₃ gas into the plasma chamber, 6.7 Pa (50 mTorr) and to the processing time to a pressure of 180 seconds And A pair of parallel plate electrodes 11a, 1 in the plasma chamber
The frequency of the high frequency power supply connected to 1b is 13.56MHz
The applied power is 10W.

When the etching amount of the SiO ₂ film 32 of the _second sample under these two conditions was measured by an optical wavelength interferometer, the results shown in FIG. 12 were obtained. That is, when the diluted hydrofluoric acid solution is used, the Si
The etching film thickness of the O ₂ film 32 increased. On the contrary,
The SiO ₂ film 32 was not etched by the ClF ₃ plasma treatment.

Next, using the first to third samples, the etching rates of silicon, silicon oxide and tungsten with respect to ClF ₃ plasma were examined. The ClF ₃ plasma generation conditions were the same as in the experiment of FIG. 12 except for the pressure. The pressure inside the chamber is 6.7Pa (50mTorr) and 13.3Pa
It was set to both (100 mTorr). Then, when the relationship between the pressure and the etching rate was investigated, the etching rate of the silicon wafer 21 increased as the pressure increased, and the etching rate increased to 17 at 13.3 Pa (100 mTorr).
It is 50Å / min. Also, for the tungsten film 34, the etching rate slightly increases when the processing pressure is 13.3 Pa (100 mTorr) than when it is 6.7 Pa (50 mTorr), and is 2 at 13.3 Pa (100 mTorr).
It was found that the etching rate was 50 Å / min and the etching rate was lower than that of the silicon wafer 31 by about one digit. Furthermore, Si
For the O ₂ film 32, 6.7 Pa (50 mTorr), 13.3 Pa (1
It can be seen that the etching rate is zero in both cases (00 mTorr), that is, ClF ₃ plasma does not function as an etchant.

Here, a typical reduction reaction of ClF ₃ gas with respect to silicon, tungsten, and SiO ₂ is shown in the following formula. Si + 4/3 ClF ₃ → SiF ₄ ↑ + 2/3 Cl ₂ ↑… (1) W + 2 ClF ₃ → WF ₆ ↑ + Cl ₂ ↑… (2) SiO ₂ + 4/3 ClF ₃ → SiF ₄ ↑ + O ₂ ↑ + 2/3 Cl ₂ ↑ (3) In this case, the free energy of formation (-ΔG) of silicon, tungsten and silicon dioxide at 300K (room temperature) and 67.0Pa (500mTorr) is as shown in Table 1. become. Here, the free energy of formation is one use that exhibits spontaneous reactivity, and as the value increases, the reduction reaction thereof easily occurs.

[0056]

[Table 1]

From now on, Si and W are more ClF ₃ than SiO _2.
It is also theoretically understood that is easily reduced, that is, easily etched selectively. From the above, as shown in FIG. 14A, the lower wiring 4 made of tungsten and the Si
When the structure having the interlayer insulating film 8 made of O ₂ and the opening 8a formed on the lower wiring of the interlayer insulating film 8 is adopted, the tungsten oxide 4a on the surface of tungsten is selectively used. Only can be selectively etched. If the conductive layer exposed from the opening 8a is a diffusion layer (not shown) of the silicon substrate, it is not preferable to treat the surface of the interlayer insulating film with chlorine fluoride plasma because the etching amount of the diffusion layer is large. .

By the way, the above chlorine fluoride plasma treatment is performed at room temperature, and in this case, the tungsten film 4 is used.
Etching is performed in the vertical direction anisotropically, but when the sample temperature is 200 ° C., the etching of the tungsten film 4 becomes isotropic as shown in FIG. The etching also reaches the periphery of the portion 8a and disconnects the wiring made of the tungsten film 4 and the titanium nitride film 3.

Therefore, it is preferable to perform the chlorine fluoride plasma treatment at a temperature of 150 ° C. or lower. Further, in order to prevent excessive etching of the tungsten film 4, the chlorine fluoride plasma treatment is preferably performed under a pressure of 10 Torr or less. Although the interlayer insulating film is formed of SiO ₂ in the above description, chlorine fluoride plasma is particularly effective for other insulating films such as SOG, PSG, BPSG, NSG, SiON and SiN. Further, the lower electrode formed under such an insulating film is formed of a refractory metal such as molybdenum or titanium, a refractory metal silicide, titanium nitride,
Even if it is made of copper or gold, the etching rate is low. Further, in the above example, Cl is used for the surface treatment of the SOG film.
Although F ₃ plasma is used, either chlorine fluoride (ClF) or chlorine pentafluoride (ClF ₅ ) plasma may be used as the gas containing fluorine and chlorine.

(Third Embodiment) In the above-described two embodiments, the cleaning of the surface of the interlayer insulating film and the surface of the conductive layer below the opening with chlorine fluoride plasma has been described. In this example, achievement of them by wet processing will be described. First, as shown in FIG. 15 (a), an insulating film 2 is formed on a Si substrate 1, a lower wiring composed of a titanium nitride film 3 and a tungsten film 4 is formed thereon, and then a lower wiring is formed. The interlayer insulating film 9 was covered, and an opening 9a was formed in the interlayer insulating film 9. As the interlayer insulating film 9 in this case, a PSG film formed by CVD was used.

A large number of such samples were prepared and the surfaces of the interlayer insulating film 9 and the tungsten film 4 were cleaned using either a mixed solution of sulfuric acid and hydrogen peroxide or diluted hydrofluoric acid. Impurities such as carbon and hydrogen compounds are present on the surface of the interlayer insulating film 9, and the tungsten layer 4 below the opening 9a.
A tungsten oxide layer 4a is formed on the surface of the.
If the Tangsutene layer 4 is immersed in the mixed solution for a long time, the tungsten layer 4 is isotropically etched to cause a disconnection or the like, so it is not preferable to set the immersion time to 30 minutes or more.

After performing either of the treatment with the mixed solution and diluted hydrofluoric acid, as shown in FIG. 15 (b),
Tungsten 10 is formed on the tungsten film 4 in the opening 9a.
Was selectively grown for 150 seconds, 200 seconds and 250 seconds, the results shown in Table 2 were obtained.

[0063]

[Table 2]

In Table 2, the number of growth nuclei on the interlayer insulating film 9 is counted by using a metallographic microscope.
The number of tungsten nuclei existing in the region of 35 × 35 μm ² is shown, and the larger the number is, the worse the selectivity is. As a result, comparing Samples 1 and 2 with Samples 3 and 4, the selective growth after the treatment with the mixed solution of sulfuric acid and hydrogen peroxide has the same growth time as compared with the selective growth after the treatment with the hydrofluoric acid solution. It is understood that the selectivity is improved as the grown film thickness with respect to is increased.

Further, comparing Samples 2, 4, and 5, it was found that sulfuric acid
It was confirmed that the selectivity was better when using the hydrogen peroxide solution mixture. Conventionally, a mixed solution of sulfuric acid and hydrogen peroxide was considered to be an oxidizing agent, but it was found that it does not actually function as an oxidizing agent. From the above, it can be seen that the surface of the interlayer insulating film 9 can be cleaned with a mixed solution of sulfuric acid and hydrogen peroxide, and the selectivity of tungsten growth is improved. In addition, the natural oxide film existing on the surface of the tungsten film 4 exposed from the opening 9a can be removed to clean the surface, which increases the selective growth rate of tungsten.

(Regarding Surface Cleaning of Interlayer Insulating Film) In the silicon wafer shown in FIG. 15, since there is a resist used for forming a pattern and carbon and its hydrogen compound attached in the atmosphere, tungsten growth by CVD is performed. Collapse of selectivity occurs. On the other hand, when pretreatment is performed using a mixed solution of sulfuric acid and hydrogen peroxide, carbon and hydrogen compounds, which are the main components of the resist residue, can be removed, so that the selectivity is improved. The reaction in a mixed solution of sulfuric acid and hydrogen peroxide is shown below.

H ₂ SO ₄ + H ₂ O ₂ → H ₂ SO ₅ + H ₂ O (4) 2H ₂ O ₂ → 2H ₂ O + O ₂ ↑ (5) These reaction formulas (4), ( Compounds of carbon and hydrogen, which are the deposits from resist residues and the atmosphere, due to the caroic acid (H ₂ SO ₅ , also known as peroxosulfuric acid) generated in 5)
(C _x H _y ) is removed by the following reaction formula.

C _x H _y + H ₂ SO ₅ → H ₂ SO ₄ + CO ₂ ↑ + H ₂ O (6) That is, a compound of carbon and hydrogen is released to the atmosphere as carbon dioxide gas by caroic acid. As a result, the surface of the interlayer insulating film is cleaned and the selectivity of tungsten growth by CVD is improved. (Removal of Oxide on Lower Wiring Surface) Caroic acid in the above reaction formula (4) is in a state shown in the following reaction formula in an aqueous solution.

H ₂ SO ₅ → 2H ⁺ + SO ₅ ²⁻ (7) When the selective growth pretreatment is performed in this solution, a natural oxide film existing on the surface of the tungsten film, that is, tungsten oxide (WO ₃ ). Are removed, so that the pure tungsten film is exposed by the following reduction reaction formula (8). WO ₃ + 6H ⁺ → W + 3H ₂ O (8) When the free energy of formation (-ΔG) of tungsten at 400 K in this reaction formula (8) is calculated, -ΔG is 2
It becomes 152 kcal / mol. Here, the free energy of formation is one index showing the spontaneous reactivity, and the reduction reaction becomes easier to occur as the value increases.

Further, it is clear from the results shown in Table 2 that the growth rate in the selective CVD is increased when the growth pretreatment is performed with the mixed solution of sulfuric acid and hydrogen peroxide.
Therefore, in a mixed solution of sulfuric acid and hydrogen peroxide, tungsten oxide is reduced and removed, pure tungsten that constitutes the lower wiring is exposed, and selective growth of tungsten is smoothly performed in the subsequent CVD. The growth rate is higher than that in the pretreatment with hydrofluoric acid.

Similarly, a natural oxide film in the case where the lower wiring which is the base of the selective growth is aluminum (Al), titanium (Ti), titanium nitride (TiN) or silicon (Si),
Aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ) and silicon oxide film (SiO ₂ ) are also reduced by using a mixed solution of sulfuric acid and hydrogen peroxide, and pure aluminum, titanium, Titanium nitride and silicon are exposed.

Al ₂ O ₃ + 6H ⁺ → Al + 3H ₂ O (9) TiO ₂ + 4H ⁺ → Ti + 2H ₂ O (10) SiO ₂ + 4H ⁺ → Si + 2H ₂ O (11) Here, the free energies (-ΔG) of formation of aluminum, titanium, titanium nitride, silicon, and tungsten at 400 K are calculated by these reaction formulas, and the results are shown in Table 3 below.

[0073]

[Table 3]

Therefore, the natural oxides of aluminum, titanium, titanium nitride, and silicon show almost the same free energy of formation as the removal of tungsten oxide by reduction. Therefore, even if the conductive layer under the interlayer insulating film is formed of these materials, the natural oxidation of the conductive layer surface is similarly removed by using the mixed solution of sulfuric acid and hydrogen peroxide, and Since the selective growth by CVD is facilitated, the selectivity is improved as compared with the hydrofluoric acid pretreatment.

A graph of the results shown in Table 2 is shown in FIG. FIG. 16 shows the growth film thickness of tungsten with respect to the growth time when either one of the mixed solution of hydrofluoric acid and hydrogen peroxide is used as the pretreatment for the selective growth. According to the selective growth after the hydrofluoric acid treatment, it can be seen that the film thickness grown in the same time is smaller than that in the treatment with the mixed solution of sulfuric acid and hydrogen peroxide. Considering from the auxiliary line shown by the broken line in FIG. 16, it is considered that the selective growth start time is faster when the mixed solution is used than when the hydrofluoric acid treatment is used. From this, it is preferable to clean the surface of the lower wiring with a mixed solution of sulfuric acid and hydrogen peroxide.

FIG. 17 shows the relationship between the film thickness of tungsten selectively grown in the opening of the interlayer insulating film and the number of tungsten nuclei on the surface of the interlayer insulating film, and the solid line shows sulfuric acid and hydrogen peroxide. The case of a mixed solution is shown, and the alternate long and short dash line shows the case of hydrofluoric acid. According to selective growth after hydrofluoric acid treatment,
As the growth film in the opening becomes thicker, the number of tungsten nuclei on the interlayer insulating film increases and the selectivity collapses. On the other hand, in the selective growth after the treatment of the mixed solution of sulfuric acid and hydrogen peroxide, the number of tungsten nuclei on the interlayer insulating film does not increase even if the growth film in the opening becomes thick, and the selectivity No collapse has occurred.

From the above, it is clear that selective growth is improved by cleaning the layer surface with a mixed solution of sulfuric acid and hydrogen peroxide as a pretreatment. In addition,
In order to keep the sulfuric acid and hydrogen peroxide in the mixed solution stable, the ratio of hydrogen peroxide in the mixed solution must be 50 wt% or less, and the temperature of the mixed solution is in the range of 20 to 200 ° C. Must be set within.

The metal for selective growth may be a refractory metal other than tungsten, such as molybdenum. When selectively growing molybdenum, molybdenum hexafluoride is used as a reaction gas.

[0079]

As described above, according to the present invention, by exposing the insulating film covering the wiring to chlorine fluoride plasma,
Since the surface of the insulating film was cleaned, and at the same time, at least the surface of the insulating film was terminated with fluorine to improve the water permeation resistance, there was no carbon, hydroxide, etc. on the surface of the insulating film, and at the same time, the insulating film It is possible to prevent the outgassing from the gas and improve the selectivity by making it difficult for metal nuclei to grow on the surface of the insulating film when selectively growing a metal such as tungsten in the opening of the insulating film.
Moreover, it is possible to prevent corrosion of the metal wiring formed on the insulating film.

Further, since chlorine fluoride plasma can simultaneously remove the oxide layer on the surface of the conductive layer below the opening of the insulating film, it is possible to selectively grow a metal on the conductive layer in the opening. The growth rate on the conductive layer can be increased to improve the selectivity. Permeability resistance by chlorine fluoride plasma
It does not change regardless of whether the insulating film is placed in the atmosphere.

By keeping the substrate temperature at 150 ° C. or lower, excessive etching of the conductive layer under the opening can be prevented.
Further, by setting the pressure of chlorine fluoride plasma to 10 Torr or less, damage to the insulating film and excessive etching of the conductive layer can be prevented. Further, by setting the power for generating plasma to 50 W or less, excessive etching of the conductive layer and damage to the insulating film can be prevented.

According to another invention, the surface of the insulating film and the conductive layer exposed from the opening can be cleaned by immersing it in a mixed solution of sulfuric acid and hydrogen peroxide. A stable reaction can be obtained by setting hydrogen peroxide in the mixed solution to 50% or less and setting the mixed solution at a temperature of 20 to 200 ° C. In addition, by setting the treatment time within 30 minutes, excessive etching of the conductive layer can be prevented.

[Brief description of drawings]

1 (a) to 1 (c) are steps of forming an opening in an interlayer insulating film of a semiconductor device according to a first embodiment of the present invention, and then subjecting the insulating film to a water permeation-resistant treatment with chlorine fluoride plasma. FIG.

FIG. 2 is a cross-sectional view showing a state in which a metal is selectively grown in the opening of the interlayer insulating film of the semiconductor device of the first embodiment of the present invention.

3 (a) is a plasma generator used in the first embodiment of the present invention, and FIG. 3 (b) is a chemical vapor deposition method (CVD) used in the first embodiment of the present invention. ) Is a selective growth apparatus of tungsten according to (1).

FIG. 4 is a cross-sectional view of a sample used for an experiment of chlorine fluoride plasma adopted in the manufacturing process of the semiconductor device of the first embodiment of the present invention.

FIG. 5 is a flow chart for a comparative test with and without chlorine fluoride plasma treatment employed in the first embodiment of the present invention.

FIG. 6 is a decompression device used for the first embodiment of the present invention for investigating the degassing amount with and without chlorine fluoride plasma treatment.

FIG. 7 is a diagram showing element concentrations on the surface of an insulating film with and without chlorine fluoride plasma treatment adopted in the first embodiment of the present invention.

FIG. 8 is a characteristic diagram showing the relationship between the chlorine trifluoride plasma treatment time and the fluorine concentration on the surface of the insulating film, wherein the vertical axis indicating the fluorine element concentration is the logarithmic scale and the horizontal axis indicating the plasma treatment time. Is a proportional scale.

FIG. 9 is a characteristic diagram showing the relationship between the chlorine trifluoride plasma treatment time and the tungsten deposition amount on the surface of the insulating film, wherein the vertical axis indicating the tungsten deposition amount is a logarithmic scale and the horizontal axis indicates the plasma treatment time. The axis is a proportional scale.

FIG. 10 is a cross-sectional view showing a state in which selective growth collapses when the power for generating chlorine trifluoride plasma adopted in the first embodiment of the present invention is large.

11 (a) is a sectional view showing a first sample used in the second embodiment of the present invention, and FIG. 11 (b) is a second sectional view showing the second sample used in the second embodiment of the present invention. Cross-sectional view showing the sample, FIG.
FIG. 1 (c) is a cross-sectional view showing a third sample used in the second embodiment of the present invention.

FIG. 12 is a characteristic diagram showing the relationship between the etching thickness and the treatment time when either hydrofluoric acid or chlorine trifluoride plasma is used in the second embodiment of the present invention. And the horizontal axis indicating the processing time are both represented on a proportional scale.

FIG. 13 is a characteristic diagram showing the relationship between the etching thickness by chlorine trifluoride plasma and the plasma atmosphere pressure for silicon, tungsten, and a silicon oxide film in the second embodiment of the present invention. Both the vertical axis indicating and the horizontal axis indicating the total pressure are represented on a proportional scale.

14 (a) and 14 (b) are cross-sectional views showing etching states of a tungsten layer due to a difference in plasma power in a second embodiment of the present invention.

15 (a) and 15 (b) are cross-sectional views showing surface treatment of an insulating film and a tungsten layer with a mixed solution of sulfuric acid and hydrogen peroxide according to a third embodiment of the present invention.

FIG. 16 is a characteristic diagram showing the relationship between the tungsten growth film pressure and the growth time for each of the treatment with the mixed solution of sulfuric acid and hydrogen peroxide and the treatment with the hydrofluoric acid solution according to the third embodiment of the present invention. And the vertical axis and the horizontal axis show proportional scales.

FIG. 17 is a diagram showing the number of tungsten nuclei on the insulating film and the tungsten selection in each of the treatment with the mixed solution of sulfuric acid and hydrogen peroxide and the treatment with the hydrofluoric acid solution according to the third embodiment of the present invention. FIG. 6 is a characteristic diagram showing a relationship between grown film thicknesses, in which the vertical axis and the horizontal axis show proportional scales.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Silicon substrate 2 Insulating film (SiO ₂ film) 3 Titanium nitride layer (wiring) 4 Tungsten (wiring) 4a Tungsten oxide (WOx) 5 SiO ₂ film (insulating film) 6 SOG film (insulating film) 6a Opening 6b Damage layer 7 Tungsten (metal) 7a Tungsten nucleus 8,9 Interlayer insulating film 8a, 9a Opening 10 Chamber 11a, 11b Parallel plate electrode 12 Gate valve 13 Chamber (growth) 14 Susceptor 15 Decompression chamber 16 Ionization vacuum gauge 17 Susceptor 21, 31 Silicon Substrate 22, 32 SiO ₂ film 23 SOG film (insulating film) 33 Titanium nitride layer 34 Tungsten layer

[Procedure amendment]

[Submission date] January 23, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

1 (a) and 1 (b) are steps of forming an opening in an interlayer insulating film of a semiconductor device according to a first embodiment of the present invention, and then subjecting the insulating film to a water permeation-resistant treatment by chlorine fluoride plasma. FIG.

FIG. 2 is a cross-sectional view showing a state in which a metal is selectively grown in the opening of the interlayer insulating film of the semiconductor device of the first embodiment of the present invention.

3 (a) is a plasma generator used in the first embodiment of the present invention, and FIG. 3 (b) is a chemical vapor deposition method (CVD) used in the first embodiment of the present invention. ) Is a selective growth apparatus of tungsten according to (1).

FIG. 4 is a cross-sectional view of a sample used for an experiment of chlorine fluoride plasma adopted in the manufacturing process of the semiconductor device of the first embodiment of the present invention.

FIG. 5 is a flow chart for a comparative test with and without chlorine fluoride plasma treatment employed in the first embodiment of the present invention.

FIG. 6 is a decompression device used for the first embodiment of the present invention for investigating the degassing amount with and without chlorine fluoride plasma treatment.

FIG. 7 is a diagram showing element concentrations on the surface of an insulating film with and without chlorine fluoride plasma treatment adopted in the first embodiment of the present invention.

FIG. 8 is a characteristic diagram showing the relationship between the chlorine trifluoride plasma treatment time and the fluorine concentration on the surface of the insulating film, wherein the vertical axis indicating the fluorine element concentration is the logarithmic scale and the horizontal axis indicating the plasma treatment time. Is a proportional scale.

FIG. 9 is a characteristic diagram showing the relationship between the chlorine trifluoride plasma treatment time and the tungsten deposition amount on the surface of the insulating film, wherein the vertical axis indicating the tungsten deposition amount is a logarithmic scale and the horizontal axis indicates the plasma treatment time. The axis is a proportional scale.

FIG. 10 is a cross-sectional view showing a state in which selective growth collapses when the power for generating chlorine trifluoride plasma adopted in the first embodiment of the present invention is large.

11 (a) is a cross-sectional view showing a first sample used in the second embodiment of the present invention, and FIG. 11 (b) is a second sectional view showing the second sample used in the second embodiment of the present invention. Sectional view showing the sample, FIG.
(c) is a sectional view showing a third sample used in the second embodiment of the present invention.

FIG. 12 is a characteristic diagram showing the relationship between the etching thickness and the treatment time when either hydrofluoric acid or chlorine trifluoride plasma is used in the second embodiment of the present invention. And the horizontal axis indicating the processing time are both represented on a proportional scale.

FIG. 13 is a characteristic diagram showing the relationship between the etching thickness by chlorine trifluoride plasma and the plasma atmosphere pressure for silicon, tungsten, and a silicon oxide film in the second embodiment of the present invention. Both the vertical axis indicating and the horizontal axis indicating the total pressure are represented on a proportional scale.

14 (a) and 14 (b) are cross-sectional views showing etching states of a tungsten layer due to a difference in plasma power in a second embodiment of the present invention.

15 (a) and 15 (b) are cross-sectional views showing surface treatment of an insulating film and a tungsten layer with a mixed solution of sulfuric acid and hydrogen peroxide according to a third embodiment of the present invention.

FIG. 16 is a characteristic diagram showing the relationship between the tungsten growth film pressure and the growth time for each of the treatment with the mixed solution of sulfuric acid and hydrogen peroxide and the treatment with the hydrofluoric acid solution according to the third embodiment of the present invention. And the vertical axis and the horizontal axis show proportional scales.

FIG. 17 is a diagram showing the number of tungsten nuclei on the insulating film and the tungsten selection in each of the treatment with the mixed solution of sulfuric acid and hydrogen peroxide and the treatment with the hydrofluoric acid solution according to the third embodiment of the present invention. FIG. 6 is a characteristic diagram showing a relationship between grown film thicknesses, in which the vertical axis and the horizontal axis show proportional scales.

[Explanation of symbols] 1 silicon substrate 2 insulating film (SiO ₂ film) 3 titanium nitride layer (wiring) 4 tungsten (wiring) 4a tungsten oxide (WOx) 5 SiO ₂ film (insulating film) 6 SOG film (insulating film) 6a Opening 6b Damage layer 7 Tungsten (metal) 7a Tungsten nucleus 8,9 Interlayer insulating film 8a, 9a Opening 10 Chamber 11a, 11b Parallel plate electrode 12 Gate valve 13 Chamber (growth) 14 Susceptor 15 Decompression chamber 16 Ionization vacuum gauge 17 Susceptor 21, 31 Silicon substrate 22, 32 SiO ₂ film 23 SOG film (insulating film) 33 Titanium nitride layer 34 Tungsten layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Juju Hara, 1015 Kamiodanaka, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Shinya Ohira, 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited

Claims (17)

[Claims] 1. A step of forming an insulating film on a substrate, a step of cleaning the surface of the insulating film by exposing the insulating film to chlorine fluoride plasma, and at the same time fluorine at least the surface of the insulating film. And a step of improving the water permeation resistance by a terminal treatment. 2. An opening is formed in the insulating film, and a part of the conductive layer under the insulating film is exposed from the opening,
2. The semiconductor device according to claim 1, further comprising the step of selectively growing a metal on the surface of the conductive layer below the opening after exposing the insulating film and the conductive layer to the chlorine fluoride plasma. Manufacturing method. 3. The step of exposing the insulating film to the chlorine fluoride plasma after the step of exposing the insulating film to the atmosphere once or entering the step of selectively growing the metal without exposing the insulating film to the atmosphere. The method for manufacturing a semiconductor device according to claim 2. 4. The semiconductor device according to claim 2, wherein the substrate temperature when exposing the insulating film and the conductive layer under the opening to the chlorine fluoride plasma is 150 ° C. or lower. Production method. 5. The semiconductor device according to claim 2, wherein only the surface of the conductive layer under the opening is selectively etched when the insulating film is exposed to the chlorine fluoride plasma. Production method. 6. The method of manufacturing a semiconductor device according to claim 2, wherein the substrate is placed under a pressure of 10 Torr or less when the insulating film is exposed to the chlorine fluoride plasma. 7. The method of manufacturing a semiconductor device according to claim 2, wherein the power for generating the chlorine fluoride plasma is 50 W or less. 8. The method of manufacturing a semiconductor device according to claim 2, wherein the substance forming the conductive layer has a lower activation energy for chemisorption than the material forming the insulating film. 9. The gas used for generating the chlorine fluoride plasma is any one of chlorine fluoride, chlorine trifluoride and chlorine pentafluoride.
The manufacturing method of the semiconductor device described in the above. 10. The semiconductor device according to claim 1, wherein the chlorine fluoride, chlorine trifluoride and chlorine pentafluoride are diluted with helium, neon, argon, xenon, kropton and nitrogen. Manufacturing method. 11. The method for manufacturing a semiconductor device according to claim 1, wherein the chlorine fluoride, chlorine trifluoride, and chlorine pentafluoride are plasmatized without being diluted. 12. The insulating film is SOG, PSG, BPS
3. The method for manufacturing a semiconductor device according to claim 1, wherein the silicon oxide film is formed using G, NSG, SiN, SiON, or an organic source gas. 13. A step of forming an insulating film, a step of forming an opening in the insulating film to expose a part of a conductive layer under the insulating film, and a step of exposing the surface of the insulating film and the conductive layer. A method of manufacturing a semiconductor device, comprising: immersing in a mixed solution of sulfuric acid and hydrogen peroxide; and, after immersing in the mixed solution, selectively growing a metal in the opening. 14. The hydrogen peroxide in the mixed solution is 50%.
14. The method for manufacturing a semiconductor device according to claim 13, wherein: 15. The method of manufacturing a semiconductor device according to claim 13, wherein the mixed solution is maintained at a temperature of 20 to 200 ° C. 16. The method of manufacturing a semiconductor device according to claim 13, wherein the time for immersing the insulating film and the conductive layer in the mixed solution is within 30 minutes. 17. The method of manufacturing a semiconductor device according to claim 2, wherein the metal is a refractory metal.