JP2011146596A - Method of manufacturing semiconductor device, semiconductor device, and semiconductor manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a cleaning time for an inner wall of a plasma reaction chamber after formation of an organic silica film. <P>SOLUTION: The plasma reaction chamber inner wall is coated with a precoat film (precoating process). Then the organic silica film having a silicon-carbon composition ratio (C/Si) of ≥1 is grown on the substrate (substrate processing process). After the substrate is taken out, the organic silica film and precoat film sticking on the plasma reaction chamber inner wall are removed using plasma (cleaning process). As the precoat film, a high-oxygen-containing precoat film is used which is an organic silica film having at least a less carbon content than the organic silica film formed on the substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor device, a semiconductor device, and a semiconductor manufacturing device including a step of forming an organic silica film on a substrate.

  In the manufacturing technology in the integrated circuit field of the electronic industry, further higher integration and higher speed are required. As miniaturization of semiconductor devices progresses in order to realize integration, wiring delay due to increase in parasitic capacitance due to the close proximity of wiring and increase in power consumption become problems. In order to avoid these problems, the dielectric constant (Low-k) of the interlayer insulating film is being reduced by introducing hydrocarbon groups and vacancies. The interlayer insulating film that has been made low-k is mainly an organic silica film (SiOCH film) made of silicon, oxygen, carbon, and hydrogen. As a method for forming these organic silica films, a plasma CVD method or a plasma polymerization method is used.

  In the plasma polymerization method, a raw material gas composed of organic silica molecules having an unsaturated hydrocarbon group is used. Specifically, a mixed gas of a source gas and a carrier gas (He) or a gas added with an oxidant gas is introduced into the plasma to mainly activate unsaturated hydrocarbon groups, and the raw material is obtained by the plasma polymerization reaction. An organic silica film having a silica skeleton structure is formed. For example, when an organic silica compound molecule having a cyclic siloxane structure is used as a starting material gas, a porous organic silica film having a cyclic siloxane structure grows.

  At this time, particularly when a bulky hydrocarbon side chain is bonded to the organic silica molecule which is the starting material, it is important to promote the polymerization reaction by heat energy and plasma energy by heating the semiconductor substrate. When a film is formed on a heated semiconductor substrate, a sufficient polymerization reaction occurs at the interface between the organic silica and the semiconductor substrate, and it becomes possible to grow an organic silica film having a porous structure with high density and excellent adhesion. An effect peculiar to the plasma polymerization method occurs. The substrate temperature is generally 200 ° C. to 450 ° C.

  When forming an organic silica film using the plasma CVD method or the plasma polymerization method, in order to stabilize the atmosphere and environment in the plasma reaction chamber, before forming the insulating film on the semiconductor substrate (wafer), A growth process of a precoat film for covering the plasma reaction chamber inner wall with an insulating film is required. The plasma reaction chamber inner wall is made of a conductive metal such as stainless steel and is not heated except in special cases.

  When the precoat film is not grown, the metal inner wall of the plasma reaction chamber is covered with the insulating film during the growth of the insulating film. That is, since the inner wall of the plasma reaction chamber changes from conductive to insulating, the plasma potential distribution in the plasma reaction chamber changes, and in particular, in the plasma polymerization method, the polymerization reactivity changes, so the film properties in the film thickness direction. Sometimes changed. Therefore, in order to suppress changes in the plasma potential distribution during the growth of the organic silica film on the semiconductor substrate, it is a common practice to perform the precoat film growth step as described above. Also, by pre-growing the precoat film, when the organic silica film is formed, particles and metal impurities originating from the plasma reaction chamber wall are taken into the film or attached to the back surface of the semiconductor substrate. It is also known that it can be prevented.

  The precoat film is removed by a plasma cleaning process after taking out the semiconductor substrate on which one or more organic silica films are formed. After the removal, the pre-coating film growth step is performed again to coat the plasma reaction chamber inner wall, and thereafter, organic silica films are continuously formed on a plurality of semiconductor substrates while repeating the above steps.

As an example of preventing particles generated from the plasma reaction chamber, Patent Document 1 can be cited. In Patent Document 1, the plasma reaction chamber wall surface is precoated by generating μ wave plasma with μ wave introduced from the introduction window of the plasma reaction chamber wall surface after the cleaning is completed. Alternatively, pre-coating is performed on the plasma reaction chamber wall surface by generating RF plasma by applying RF to the plasma reaction chamber wall surface after completion of cleaning. Alternatively, after the cleaning is completed, RF plasma is applied to the substrate electrode to generate RF plasma, thereby pre-coating the wall surface of the plasma reaction chamber. Oxygen gas, Ar, or SiH ₄ gas is used as a film forming gas. In the cleaning for removing the precoat film, NF ₃ gas is used.

Further, Patent Document 2 can be cited as an example of preventing peeling of a film deposited in the plasma reaction chamber. In Patent Document 2, a precoat film including a silicon oxide film and a silicon nitride film is deposited in a quartz reaction tube of a low pressure CVD apparatus. By laminating a silicon oxide film that serves as a stress buffer layer and a silicon nitride film that improves adhesion, film peeling caused by film stress from the inner wall of the quartz reaction tube is suppressed and particle generation is suppressed. is doing. These laminated films are removed by gas cleaning using thermally decomposed NF ₃ gas.

Moreover, although the film | membrane deposited in the plasma reaction chamber is removed by cleaning, patent document 3 can be mentioned from a viewpoint of utilizing the cleaning gas used for this cleaning efficiently. The NF ₃ gas activated by plasma or the like outside the process chamber loses energy and loses its active state by colliding with the side wall of the pipe before being supplied to the process chamber via the gas pipe. (Deactivation). In Patent Document 3, by using a plurality of plasma sources, the cleaning gas once deactivated can be activated again. As a result, gas cleaning efficiency can be increased. Patent Document 3 describes, as an example, a case where NF ₃ is used as a cleaning gas.

When a SiO ₂ film or a SiN film is used as the precoat film, it is common that a cleaning gas is a combination of NF ₃ or NF ₃ and argon (Ar). NF ₃ gas is activated using these gases and remote plasma, and silicon atoms contained in the SiO ₂ film or SiN film are removed as SiF by fluorine radicals generated from the NF ₃ plasma. For oxygen atoms or nitrogen atoms, the respective films are removed as oxygen gas or nitrogen gas, respectively, and cleaning is performed.

JP 2001-123271 A JP 2008-117987 A JP 2005-101309 A

When the present inventors grow a general organic silica film having a carbon / silicon ratio of 1 or less (C / Si ≦ 1) on a semiconductor substrate, the organic silica film having the same composition as a precoat film on the inner wall of the plasma reaction chamber Was considered to form a film. In this case, when the organic silica film is grown on the semiconductor substrate, the organic silica film is also deposited on the plasma reaction chamber wall. Therefore, after the organic silica film is grown on the semiconductor substrate, a single layer film of the organic silica film is grown on the inner wall of the plasma reaction chamber. In the case of general organic silica with C / Si ≦ 1, plasma cleaning of the plasma reaction chamber inner wall can be performed using NF ₃ . It is considered that silicon in the organic silica is removed as SiF and oxygen by reaction with fluorine radicals, and carbon is further removed as CO ₂ or CO. At this time, oxygen bonded to carbon is supplied from oxygen constituting the organic silica (SiOCH film). In general, many organic silica films known as SiOCH films have a carbon / silicon composition ratio (C / Si ratio) of less than 1 and an oxygen / silicon composition ratio (O / Si) of greater than 1.5. With such an organic silica film having a low carbon composition, cleaning with NF ₃ gas can be performed in the same manner as the silicon oxide film.

  Here, in the plasma polymerization method, the present inventors have grown an organic silica film (SiOCH) rich in carbon composition, specifically, an organic silica film having C / Si> 1 in the plasma reaction chamber. It has been found that cleaning has the following problems.

When an organic silica film having a high carbon composition, specifically C / Si> 1, is subjected to plasma cleaning using NF ₃ , carbon in the film is removed as CO ₂ or CO. Is relatively deficient in oxygen. As a result, the cleaning speed decreases and the time required for cleaning increases.

In order to make up for this lack of oxygen, it is possible to add oxygen to the cleaning gas NF _3. However, if the amount of oxygen added is increased in accordance with the increase in the carbon composition of the organic silica film, this time, NF ₃ Gas is easily deactivated. More specifically, the activated NF ₃ gas is deactivated by colliding with the added oxygen, whereby the cleaning rate cannot be increased, and the cleaning rate is finally lowered.

  In the case of forming an organic silica film rich in carbon composition (C / Si> 1), particularly an organic silica film rich in carbon composition having a porous structure by plasma polymerization, the organic silica film The use of a high oxygen content precoat film having a lower carbon composition was considered.

That is, according to the present invention, a precoat step of coating the plasma reaction chamber inner wall with a precoat film,
A substrate processing step of growing an organic silica film having a silicon carbon composition ratio (C / Si) of 1 or more on the substrate;
A cleaning step of removing the organic silica film and the precoat film adhering to the plasma reaction chamber wall using plasma after taking out the substrate;
A semiconductor device manufacturing method using a high oxygen content precoat film which is an organic silica film having at least a carbon content lower than that of the organic silica film as the precoat film is provided.

  After the growth of the organic silica film on the substrate, a laminated film in which an organic silica film rich in carbon composition is deposited on the high oxygen-containing precoat film is formed on the plasma reaction chamber inner wall. The high oxygen content precoat film has a higher oxygen content than the organic silica film rich in carbon composition. For this reason, the high-oxygen-containing precoat film becomes an oxygen supply source, and as a result, the cleaning time by plasma can be greatly shortened.

  According to the present invention, there is provided a semiconductor device characterized in that an organic silica film manufactured using the above-described method for manufacturing a semiconductor device is used as an interlayer insulating film.

According to the present invention, there is provided a semiconductor manufacturing apparatus for performing the above-described semiconductor device manufacturing method,
A plasma reaction chamber having a mechanism for heating the substrate;
A film forming gas supply unit for gasifying a cyclic organic silica compound for growing an organic silica film rich in carbon composition and supplying the gas to a plasma reaction chamber;
A precoat source gas supply unit for supplying a silane gas and an oxidant gas for growing a precoat film to the plasma reaction chamber;
A cleaning gas supply unit for supplying a cleaning gas to the plasma reaction chamber;
An exhaust system;
A semiconductor manufacturing apparatus is provided.

  According to the present invention, the cleaning time by plasma can be greatly shortened.

It is a figure showing the composition of the semiconductor manufacturing device concerning an embodiment. It is a figure which shows the diameter distribution of the void | hole contained in the organic silica film formed by the method which concerns on embodiment. It is a diagram showing the relationship between the deposition rate and N _{2 O} amount of the organic silica film. It is a figure which shows the result of the Fourier-transform infrared spectroscopy analysis (FT-IR) of the organic silica film | membrane in this embodiment. It is a figure which shows the result of having monitored the cleaning state in Example 1 and each comparative example using the emission spectrometer. It is a figure which shows the result of having monitored the cleaning state in Example 2 and Example 1 using the emission spectrometer. It is a figure which shows the result of having monitored the cleaning state in Example 3 using the emission spectrometer. It is a figure which shows the result of having monitored the cleaning state in Example 4 and each comparative example using the emission spectrometer. FIG. 9 is a cross-sectional view showing a configuration of a semiconductor device according to Example 5. FIG. 10 is a cross-sectional view showing a configuration of a semiconductor device according to Example 6.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

The manufacturing method of the semiconductor device according to the embodiment includes the following steps. First, the inner wall of the plasma reaction chamber is covered with a precoat film (precoat process). Next, an organic silica film having a silicon carbon composition ratio (C / Si) of 1 or more is grown on the substrate (substrate processing step). Next, after taking out the substrate, the organic silica film and the precoat film adhering to the inner wall of the plasma reaction chamber are removed using plasma (cleaning step). As the precoat film, an organic silica film having at least a lower carbon content than the organic silica film formed on the substrate, or a high oxygen content precoat film that is a silica (SiO ₂ ) film is used.

In the above-described method, after the organic silica film is grown on the substrate, a laminated film in which an organic silica film rich in carbon composition is deposited on the high-oxygen-containing precoat film is formed on the plasma reaction chamber inner wall. An example of the high oxygen content precoat film is a silica film (SiO ₂ , C / Si = 0, O / Si = 2). Thereby, in the cleaning process of the inner wall of the plasma reaction chamber, the cleaning time by the plasma is significantly shortened in the laminated film than in the single layer film of the organic silica film rich in carbon composition. By shortening the plasma cleaning time, the amount of expensive cleaning gas such as nitrogen trifluoride (N _F 3) -argon (Ar) -oxygen (O ₂ ) can be reduced. The manufacturing cost of the semiconductor device using the film can be greatly reduced. Details will be described below.

[Principle of the Invention]
In case of cleaning an organic silica film rich in carbon composition with NF _3, the carbon atoms of fluorine and organic silica film of NF ₃ recombine to form a CF-based deposit. Since NF ₃ cannot efficiently remove CF-based deposits, this reduces the cleaning rate. For example, when an organic silica film rich in carbon composition is used for pre-coating as in this film formation, the surface inside the plasma reaction chamber is always covered with an organic silica film rich in carbon composition, and the entire surface is removed. Takes a very long time. On the other hand, in the present embodiment, the plasma cleaning time of the organic silica film rich in carbon composition is shortened by using the precoat film containing high oxygen.

In the plasma cleaning process of the plasma reaction chamber wall, the organic silica film rich in carbon composition grown on the plasma reaction chamber wall is sequentially removed from the site where the NF ₃ radical is supplied, and the film thickness is reduced. Eventually, the high oxygen content precoat film is exposed. At this time, there is a distribution in the etching rate of the deposited film by the NF ₃ gas cleaning of the plasma reaction chamber inner wall. For this reason, exposure of the high oxygen content precoat film is started at a high cleaning rate. That is, in the cleaning process, the plasma reaction chamber inner wall is in a state where the organic silica film rich in carbon composition and the precoat film containing high oxygen are mixed.

In the plasma reaction chamber, a silicon oxide film that does not partially contain carbon is exposed, or a silicon oxide film layer exists under the organic silica film rich in carbon composition. It becomes an oxygen supply source and effectively increases the oxygen concentration in the cleaning gas. Moreover, since this oxygen is supplied by decomposing the silicon oxide film by etching with NF ₃ , it is in an active state at the time of supply, and the effect of extracting carbon in the organic silica film is high. In addition, since it is supplied in the plasma reaction chamber, the supply path of the NF ₃ radical is not affected, and the activity of NF ₃ is not lowered. The effect is that as the organic silica film rich in carbon composition remaining in the reactor is removed, the area occupied by the high-oxygen-containing precoat film on the plasma reaction chamber wall increases. The removal rate of the organic silica film rich in carbon composition is increased.

  Due to these synergistic effects, even when an organic silica film rich in carbon composition is used, cleaning is performed more efficiently than when the amount of oxygen added to the etching gas is simply increased. The shortening effect is obtained.

The effect of increasing the speed of plasma cleaning becomes more remarkable as the carbon composition of the organic silica film formed on the semiconductor substrate is higher and as the oxygen content in the precoat film is higher. In this sense, a silica film (SiO ₂ , C / Si = 0, O / Si = 2) is one of the optimum materials for the high oxygen content precoat film. The silica film is generally grown at a low cost and at a high speed by a plasma CVD method using a mixed gas of silane gas (SiH ₄ ) or tetraethoxyorthosiloxane (TEOS) gas and an oxidizing gas (for example, N ₂ O or O ₂ ). be able to.

  The above effect is not only when the silica film (silicon oxide film) is pre-coated, but also has a significantly lower carbon composition than the organic silica film used for the main film formation on the substrate, preferably carbon / silicon. If the composition ratio is smaller than about 1, the effect of shortening the cleaning time more dramatically is exhibited.

  Hereinafter, it demonstrates using drawing based on embodiment. In addition, this invention is not limited at all by the following embodiment. Hereinafter, the above-described precoat process is simply referred to as precoat. The substrate processing step is referred to as main film formation. The above-described cleaning process is simply referred to as cleaning.

  First, FIG. 1 is a schematic diagram illustrating a configuration of a semiconductor manufacturing apparatus that performs a method of manufacturing a semiconductor device according to an embodiment. This equipment controls and introduces a raw material monomer raw material supply system (film formation gas supply unit), a pipe for introducing vaporized raw material monomer supplied from the raw material into the plasma reaction chamber 201, and an additive gas for precoat film or main film formation. A plasma reaction chamber 201 that performs film formation by exciting plasma with a high-frequency power source, a plasma source (remote plasma) that excites plasma of a cleaning gas outside the plasma reaction chamber 201, and a plasma that uses the excited cleaning gas as plasma It consists of a pipe for introducing into the reaction chamber 201 and an exhaust system for discharging each unreacted gas or product by cleaning.

  Specifically, the plasma reaction chamber 201 is connected to a vacuum pump 209 via an exhaust pipe 207, an exhaust valve 222, and a cooling trap 208. Thereby, the inside of the plasma reaction chamber 201 can be decompressed by operating the vacuum pump 209. Further, by using a throttle valve (not shown) installed between the plasma reaction chamber 201 and the vacuum pump 209, the pressure in the plasma reaction chamber 201 can be controlled. Inside the plasma reaction chamber 201, a wafer stage 203 having a heating function is provided. When performing this film formation, the substrate 210 is placed on the wafer stage 203.

  First, the precoat process will be described. In this embodiment, it is desirable that the precoat film has a small carbon composition. Therefore, as an embodiment having the smallest composition, a case where a silicon oxide film is used as the precoat film is shown here.

In pre-coating, after the plasma reaction chamber 201 is evacuated, SiH ₄ and N ₂ O are introduced into the plasma reaction chamber 201 through the additive gas flow rate controllers 236 and 234 as source gases. SiH ₄ and N ₂ O are introduced into the plasma reaction chamber 201 at a set flow rate. Thereafter, after the inside of the plasma reaction chamber 201 is stabilized at the set pressure, a high frequency is applied between the shower head 204 and the wafer stage 203 to generate plasma in the plasma reaction chamber 201. As a result, a silicon oxide film as a precoat film is deposited in the plasma reaction chamber 201. The thickness of the precoat film needs to be a film thickness that prevents contamination from the inside of the plasma reaction chamber 201, and is preferably 50 nm or more. On the other hand, if the precoat film is too thick, the precoat film formation time and the cleaning time become long. Therefore, the film thickness of the precoat film is more preferably 200 nm or more and 500 nm or less. As a matter of course, a silicon oxide film is preferentially deposited on the semiconductor substrate holding portion including the shower head 204 and the wafer stage 203 existing in the space where the plasma is generated.

  The present embodiment is a parallel plate type plasma apparatus. In this apparatus, all the parts such as the inner wall of the plasma reaction chamber 201, the shower head 204, and the semiconductor substrate holding part are heated, and not only from the energy obtained from the plasma but also from a heat source such as a heater when forming the precoat film Films are also formed by receiving the obtained energy.

  After the desired silicon oxide film is coated on the inner wall of the plasma reaction chamber 201, the introduction of the high-frequency power and the source gas is terminated, and the residual gas and the like are evacuated to prepare for the next film formation as the next step. .

Since it is important that the precoat film has a smaller carbon composition than the precoat film of this film formation, a SiOCH film having a low carbon composition, specifically, C / Si <1, other than the silicon oxide film. It may be. Such a SiOCH film may be formed by using a cyclic organic silica compound raw material having a cyclic siloxane structure described later and simultaneously supplying at least one of SiH ₄ and N ₂ O. . Further, the precoat film may be formed by introducing a raw material gas composed of a cyclic organic silica compound, which will be described later, into plasma after adding an oxidant gas. This is the pre-coating process.

  Next, the film forming process will be described. A substrate 210 is introduced into a wafer stage 203 in the plasma reaction chamber 201 from a wafer transfer chamber (not shown) into the plasma reaction chamber 201 that has been pre-coated with a film having a low carbon composition. The substrate 210 on which the main film is formed is either a conductor, a semiconductor, an insulating film, or a substrate 210 formed over the semiconductor device. In this embodiment, the substrate 210, for example, a silicon substrate is used.

  The cyclic organic silica compound raw material (liquid) having a cyclic siloxane structure, which is a raw material monomer of the present embodiment, is pressurized and pressurized by the pressurized gas from the raw material reservoir tank 226 and is vaporized in the vaporizer 216, and the valve 221 and the vaporized raw material supply pipe Through 215, it is supplied into the plasma reaction chamber 201 together with a carrier gas (for example, a rare gas). The flow rate of the cyclic organic silica compound having a cyclic siloxane structure is adjusted by the liquid flow rate controller 223. A valve 225 is provided between the liquid flow controller 223 and the raw material reservoir tank 226, and a valve 224 is provided between the liquid flow controller 223 and the vaporizer 216.

  The vaporized raw material monomer can maintain the gas phase as long as the saturated vapor pressure is not exceeded. The supply pipe from the vaporizer 216 to the plasma reaction chamber 201 is heated by a heater including a valve, and the pressure rises locally by using the vaporized raw material supply pipe 215 and the valve 221 having a large flow path cross-sectional area. And re-liquefaction of the raw material can be prevented. Further, by taking an apparatus layout in which the vaporizer 216 is close to the plasma reaction chamber 201, it is possible to shorten the mutual piping distance and reduce the pressure loss due to the piping, thereby increasing the vapor pressure that can be vaporized, Raw material supply capacity can be expanded.

  The cyclic organic silica compound gas and the carrier gas introduced into the plasma reaction chamber 201 are dispersed by a shower head 204 having a large number of through holes and installed in the plasma reaction chamber 201. A gas dispersion plate (not shown) may be provided above the shower head 204.

  The shower head 204 is connected to a high-frequency power source (RF (Radio-Frequency) power source) 213 via a power supply line 211 and a matching controller 212, and is connected to a wafer stage 203 grounded via a ground line 206. Electric power (RF power) is supplied. Thereby, plasma is generated. This plasma is a rare gas plasma or a plasma containing a rare gas as a main component. The starting material gas is introduced into the plasma.

  At the same time as receiving the thermal energy from the substrate heating unit on the surface of the substrate 210, the raw material monomer undergoes a polymerization reaction by receiving the energy of the plasma generated by the RF power applied between the shower head 204 and the wafer stage 203. A plasma polymerization film, that is, a low-k film is formed on the surface. In particular, when plasma polymerization is performed using bulky organic silica molecules in which two side chains composed of a saturated hydrocarbon group and an unsaturated hydrocarbon group are bonded to a silicon atom in a cyclic silicon skeleton, plasma energy and thermal energy are used. It is important to promote the polymerization reaction by both. This makes it possible to grow an organic silica film in which the polymerization reaction has sufficiently progressed even in the interface layer with the substrate 210, and the adhesion is greatly improved. That is, the heating of the substrate 210 is very preferable, the wafer stage 203 is heated by a heater, and the temperature is preferably 200 ° C. to 450 ° C. The organic silica film preferably has a porous structure in which pores are dispersed.

As a matter of course, an organic silica (SiOCH) film is formed not only on the wafer but also in a space where plasma is generated. Since the inner wall of the plasma reaction chamber 201 is coated with the silicon oxide film by the above-described precoat, the reactor side wall, the shower head 204, or the wafer stage 203 is formed on the silicon oxide film in a region where no wafer is placed. An organic silica (SiOCH) film is deposited. As will be described in detail later, this organic silica (SiOCH) film is a film rich in carbon composition, and the composition ratio C / Si is 1 or more, for example, greater than 2. As a matter of course, the carbon composition of the silicon oxide film deposited by the precoat using SiH ₄ and N ₂ O as the source gas is zero, and the composition ratio C / Si is smaller than 1.

In addition, the portion of the wafer stage 203 on which the wafer is placed at the time of the main film formation is masked by the presence of the substrate 210, and an organic silica film rich in carbon composition is not deposited. Therefore, on the wafer stage 203, the film forming process is completed with SiO ₂ representing the cleaning acceleration effect exposed from the beginning.

  In order to further strengthen the adhesion between the organic silica film and the base, the base surface can be plasma-treated before the main film formation. By this process, the adsorbed molecules on the base are removed and the base is hardened, so that the adhesion strength can be improved.

  Furthermore, by changing the RF output from the high-frequency power source 213 or changing the ratio of excited species other than the source gas (for example, carrier gas) at the initial stage of the main film formation, the film composition and the film structure can be changed. It is possible to provide modulation. Further, film formation using two frequencies that simultaneously apply not only high frequencies but also low frequencies of 1 MHz or less can be similarly performed to modulate the film composition and the film structure. A low-frequency power source (not shown) may be connected to the shower head 204 as well as the high-frequency power source 213 shown in FIG. Such modulation can harden the portion in contact with the base and increase the adhesion to the base. Examples of the film hardening method include increasing the RF output and increasing the proportion of excited species other than the source gas.

  Such film composition and film structure modulation can also be applied to the final stage of the film formation. Such modulation can increase the adhesion to the upper and lower layers. The initial stage of film formation here means, for example, within 30 seconds after turning on the high-frequency input, and more preferably within 15 seconds. The end of film formation is, for example, within 30 seconds before turning off the high-frequency input, and more preferably within 15 seconds.

  Since the plasma reaction chamber 201 is depressurized by the vacuum pump 209, the unreacted raw material reaches the cooling trap 208 through the exhaust pipe 207 heated by the heater in the gas phase. In the cold trap 208, since the temperature is low, the raw material monomer cannot be kept in the gas phase and is liquefied or solidified in the cold trap 208. The raw material monomer is not sent to the vacuum pump 209 and is collected in the cooling trap 208.

  After a desired organic silica film is formed on the substrate 210, the introduction of high-frequency power and the introduction of the raw material gas are terminated, and the residual gas or the like is evacuated to prepare for the next cleaning process.

  Here, the details of the raw material for forming the organic silica film will be described.

  As the cyclic organic silica compound having a cyclic siloxane structure as a raw material monomer in the film forming step, it is preferable to use an organic siloxane having a Si—O cyclic structure represented by the chemical formula (3).

（３）

(3)

  In the chemical formula (3), R1 and R2 are hydrogen or a hydrocarbon group having 1 to 4 carbon atoms, and R1 and R2 may be the same or different. n shall be 2-5.

  Further, it is preferable that R1 and R2 in the chemical formula (3) use at least one linear unsaturated hydrocarbon group having 2 to 4 carbon atoms or a branched saturated hydrocarbon group having 3 to 4 carbon atoms. It is. N is preferably 3 or 4. Furthermore, n = 3 is desirable from the viewpoint of reducing the pore diameter of the porous insulating film. That is, when n> 4, the ring structure becomes unstable, it is difficult to be decomposed in the plasma and to maintain its skeleton structure, and the vapor pressure is increased and it is difficult to vaporize. In the case of n = 2, the silica skeleton becomes unstable as a tetragon and is easily decomposed in plasma. From the viewpoints of structural stability and vaporization characteristics, cyclic organic silicas with n = 3 and 4 exhibit equivalent properties, but n = 3 has a smaller inner pore diameter in the cyclic structure. The inner pore diameter of the cyclic organic silica corresponds to the pore diameter of the porous insulating film obtained from the raw material. Therefore, n = 3 is more desirable as an interlayer insulating film for ULSI multilayer copper wiring that requires finer holes.

（１） Specifically, examples of the organic siloxane represented by the chemical formula (3) include those having an unsaturated hydrocarbon group having a vinyl group, such as a trivinylcyclotrisiloxane derivative represented by the chemical formula (1).

(1)

In the chemical formula (1), R1 to R3 are hydrogen or a saturated hydrocarbon group having 2 to 4 carbon atoms, and R1 to R3 may be the same or different. Examples of the saturated hydrocarbon group corresponding to R1 to R3 include an ethyl group (—CH ₂ CH ₃ ) or a propyl group (—CH ₂ CH ₂ CH ₃ ).

The saturated hydrocarbon group corresponding to R1 to R3 preferably contains three or more carbon atoms and has a branched structure. Examples thereof include an isopropyl group (—CH (CH ₃ ) ₂ ) or a tertiary butyl group (— C (CH ₃ ) ₃ ).

（２） More preferably, 1,3,5-triisopropyl-1,3,5-trivinyl-cyclotrisiloxane represented by formula (2) can be used as the cyclic organic silica compound having a cyclic siloxane structure.

(2)

  In the present invention, a cyclic organic silica compound having one of the side chains bonded to the silicon atoms constituting the cyclic organic silica compound having a saturated hydrocarbon group containing two or more carbon atoms is used as a raw material. By using cyclic organic silica, which is a saturated hydrocarbon group containing two or more carbon atoms, having a larger steric hindrance than a methyl group, in the side chain of the saturated hydrocarbon group, a cyclic structure in which the carbon atom is one saturated hydrocarbon group The obtained film density can be reduced as compared with the case of using organic silica, and as a result, the relative dielectric constant of the obtained organic silica film can be reduced to 2.6 or less.

  Further, the pores of the organic silica film have a cyclic siloxane trimer structure made of Si—O in the film, so that a porous insulating film having a smaller pore diameter than the conventional one can be obtained. As shown in FIG. 2, the pore diameter measured by the small angle X-ray scattering method can be reduced to a maximum value of 2 nm or less and a maximum frequency pore diameter of 1 nm or less.

  It seems that two side chains of an unsaturated hydrocarbon group and a saturated hydrocarbon group having 2 or more carbon atoms are bonded to each silicon atom in the cyclic organic silica compound used in this embodiment. In particular, sufficient energy is required to sufficiently polymerize cyclic silica molecules having a large bulk density. For this reason, in this embodiment, it is preferable to perform the plasma polymerization reaction based on the plasma energy and the thermal energy applied from the wafer stage. That is, the plasma polymerization reaction is promoted by the synergistic action of plasma energy and thermal energy. If the side chain contains an unsaturated bond, the addition reaction is promoted, the film formation rate is improved, and a porous film having a network network structure can be formed.

  What is characteristic is that carbon in the raw material is released and activated by promoting the polymerization reaction. For example, when the cyclic siloxane trimer (6-membered ring) raw material shown in Example 1 described later is used, the carbon ratio in the film is C / Si ratio of the raw material = 5 from the composition analysis result of the elements in the film. Compared to the above, it was confirmed that the C / Si ratio in the porous insulating film = 2.52 and that the number of carbons was reduced by 1 to 2 compared with that in the raw material. Thus, since the polymerization reaction is sufficiently performed by promoting the polymerization reaction and the carbon in the raw material is released and activated, the C / Si ratio in the film is 1 than the raw material C / Si = 5. More or less. As a result, it is possible to stably obtain an insulating film having a low relative dielectric constant.

  When the carbon composition is high, the carbon contained in the hydrocarbon group connected to the silicon atom may be reduced when the carbon is extracted from the surface of the organic silica film by various processes in the semiconductor device manufacturing process. Since extraction occurs from carbon that is distant from the atoms, rapid carbon extraction can be suppressed. This makes it difficult for carbon to be extracted by each process deeply into the film. As a result, carbon is only extracted on the surface of the nanometer-level electrode film, and the characteristics and performance as an organic silica film are maintained. It will be. It can be said that the film has a high damage resistance.

  In particular, the cyclic organic silica compound having a cyclic siloxane structure preferably contains both a hydrocarbon group having at least 3 carbon atoms and an unsaturated hydrocarbon group. In this way, the siloxane structure includes both an unsaturated hydrocarbon group and a hydrocarbon group having 3 or more carbon atoms, thereby reducing the decarbonization rate due to the strong binding energy of the unsaturated hydrocarbon group, and the number of carbon atoms A hydrocarbon group with a large amount keeps a large amount of hydrocarbon components, and an organic silica film rich in carbon composition can be obtained.

  In addition, carrier gas can be introduced into the pipe via a gas flow rate controller 218 and a valve 220. As the carrier gas, a rare gas such as helium (He), argon (Ar), neon (Ne), or xenon (Xe) can be used.

  What is important here is a plasma that preferentially activates the unsaturated hydrocarbon group bonded to the cyclic silica skeleton without destroying the cyclic silica skeleton. The rare gas, He, Ne, Ar, and Kr plasmas are effective for the selective activity of unsaturated hydrocarbons.

Further, the plasma of the mixed gas obtained by mixing the oxidant gas with the rare gas promotes the selective activation of unsaturated hydrocarbon groups, and remarkably improves the growth rate of the porous insulating film. Although the exact accelerating reaction mechanism is not known at this time, a part of carbon in the unsaturated hydrocarbon group is combined with oxygen and extracted as CO or CO ₂ , and then the cyclic organic silica compound via the remaining carbon radical Is presumed to polymerize.

Further, for example, oxygen (O ₂ ), carbon dioxide (CO ₂ : not shown), carbon monoxide (CO: not shown), dinitrogen monoxide (N ₂ ) through the additive gas flow controller 234 and the valve 233. O) and nitrogen dioxide (NO ₂ : not shown), alcohol (not shown), phenol (not shown), or an oxidizing gas which is a plurality of mixed gases selected from these is added can do. The alcohol used here is, for example, methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, normal butyl alcohol, or isobutyl alcohol.

By adding these oxidant gases, it is possible to increase the growth rate while keeping the chemical composition of the organic silica (SiOCH) film constant. FIG. 3 shows the relationship between the film formation rate and the N ₂ O addition amount as an example of the addition of the oxidant gas.

The horizontal axis represents the supply amount of N ₂ O (sccm), and the vertical axis represents the deposition rate (nm / min). As shown in the figure, the deposition rate increases with an increase in the amount of N ₂ O added. This is an important effect in improving throughput and reducing raw material costs. In other words, throughput and raw material utilization efficiency can be improved by adding N ₂ O during film formation. The composition analysis results of the elements in the film obtained by the X-ray photoelectron spectroscopy (XPS) method shown in Table 1 show that the oxygen, carbon, and hydrogen composition ratios tend to slightly increase, but the film composition is increased by adding N ₂ O gas. Is confirmed to have not changed significantly. As described above, when the cyclic siloxane trimer (6-membered ring) raw material of (Formula 2) is used, the carbon ratio in the film is determined from the compositional analysis result of the elements in the film. Compared to 5, the C / Si ratio in the porous insulating film = 2.52, and 1 to 2 carbons are reduced compared to the raw material. Further, when 80 sccm of N ₂ O is added, C / Si ratio = 2.32, and it is confirmed that the number of carbon is reduced by 1 to 2 as compared with the raw material.

Also, from the results of Fourier transform infrared spectroscopy (FT-IR) shown in FIG. 4, even when N ₂ O is added, there is no significant change in the absorption spectrum, and there is no significant change in the film structure / composition. It suggests.

Growth of a porous insulating film simply made of a cyclic organic silica compound by adding N ₂ O as an oxidant gas to the vapor of the cyclic organic silica compound that is a saturated hydrocarbon group containing two or more carbon atoms In addition to increasing the speed, it is possible to reduce the dielectric constant while keeping the film properties and composition substantially constant.

  Next, the cleaning process will be described.

  As described so far, through the pre-coating process and the main film forming process, SiOCH films having different carbon compositions are laminated on the inner wall of the plasma reaction chamber 201, the shower head 204, the wafer holding part, and the like. In the present embodiment, a silicon oxide film having a zero carbon composition is formed as the lower layer film. In the present embodiment, the cleaning configuration will be described below assuming such a deposition state.

In cleaning, the inside of the plasma reaction chamber 201 is once evacuated, and in this embodiment, fluoride gas and Ar, for example, NF ₃ and Ar, a gas flow rate controller and an inductively coupled remote plasma source are used as cleaning gases. After activating the NF ₃ gas, the gas is introduced into the plasma reaction chamber 201 via the pipe 239. In the present embodiment, in order to improve the cleaning rate of the organic silica (SiOCH) film having a high carbon concentration, oxygen is also introduced into the plasma reaction chamber 201 after passing through the gas flow rate controller. The amount of oxygen added was set to less than 10% of the Ar concentration so as not to lower the activity of NF ₃ . Further, for the same reason, the gas flow rate of each NF ₃ was set to be in the range of 20 to 25%. In the present embodiment, NF ₃ = 1.2 SLM, Ar = 5.0 SLM, and O ₂ = 0.45 SLM are specifically set.

The cleaning plasma uses remote plasma with high radical generation efficiency, but may be a capacitively coupled type that is a parallel plate or an inductively coupled type. The activation of the NF ₃ gas alone may use heat from a pipe heater or the like. In particular, when any one of C ₂ F ₆ , C ₃ F ₈ , C ₃ F ₆ , C ₄ F ₁₀ , C ₄ F ₈ , and C ₄ F ₆ is used as the cleaning gas, or at least one of them is used. The same applies to the case of using a mixed gas of two gases and an oxidizing gas such as oxygen.

  The cleaning gas introduced from the upper part of the plasma reaction chamber 201 is dispersed by the shower head 204 in the same manner as the raw material for the film formation. Thereafter, the precoat film and the organic silica film deposited in the plasma reaction chamber 201 are sequentially etched and removed from the surface side having a high carbon concentration.

  At this time, since remote plasma is used, cleaning of the laminated precoat film and organic silica film deposited on the inner wall of the plasma reaction chamber 201 proceeds relatively uniformly. However, as described above, the precoat film and the organic silica film deposited by the main film deposition are preferentially deposited thickly on the shower head 204 and the substrate holder (for example, the wafer stage 203). Thereby, the lower silicon oxide film is first exposed from the region where the organic silica (SiOCH) film having a high carbon concentration is thinly deposited.

On the other hand, as described above, only the precoat film is deposited on the portion of the wafer stage 203 on which the substrate 210 is placed, and the organic silica film rich in carbon composition is not deposited. Therefore, in this embodiment, SiO ₂ is exposed on the wafer stage 203 at the start of cleaning.

In case of cleaning an organic silica film rich in carbon composition with NF _3, the carbon atoms of fluorine and organic silica film of NF ₃ recombine to form a CF-based deposit. Since NF ₃ cannot efficiently remove CF-based deposits, this reduces the cleaning rate. For example, when an organic silica film rich in carbon composition is used for pre-coating as in this film formation, the surface inside the plasma reaction chamber is always covered with an organic silica film rich in carbon composition, and the entire surface is removed. Takes a very long time.

However, as in this embodiment, since the silicon oxide film that does not partially contain carbon is exposed in the plasma reaction chamber 201, this surface serves as an oxygen supply source, and effectively in the cleaning gas. This will increase the oxygen concentration. Moreover, since this oxygen is supplied by decomposing the silicon oxide film by etching with NF ₃ , it is in an active state at the time of supply, and the effect of extracting carbon in the organic silica film is high. In addition, since it is supplied in the plasma reaction chamber 201, the supply path of the NF ₃ radical is not affected, and the activity of NF ₃ is not lowered. Due to these synergistic effects, even when using an organic silica film rich in carbon composition, it is possible to perform extremely efficient cleaning more than simply increasing the amount of oxygen added, dramatically reducing the cleaning time. An effect is obtained. This effect is effective not only in the case where a silicon oxide film is used as a precoat, but also in a film having a significantly lower carbon composition than the organic silica film used in this film formation, for example, a carbon / silicon composition ratio of less than 2. Preferably, if the carbon / silicon composition ratio is smaller than about 1, an effect of shortening the cleaning time more dramatically is exhibited.

  Next, this embodiment will be summarized.

When an organic silica film rich in carbon composition is used as the precoat film, the fluorine of NF ₃ and the carbon of the organic silica film may recombine to form a CF-based deposit. Since NF ₃ cannot efficiently remove CF-based deposits, when such deposits are formed, the plasma cleaning rate further decreases.

  In addition, an organic silica film rich in carbon composition is excellent in plasma resistance and has an effect of reducing process damage, but on the other hand, adhesion is generally deteriorated due to rich carbon composition. For this reason, when the organic silica film itself rich in carbon composition is adopted as the precoat film, it is recognized that the precoat film is peeled off from the inner wall of the plasma reaction chamber 201 and becomes a dust generation source. In particular, in the case of the plasma polymerization method, the inner wall of the plasma reaction chamber is not heated and generally has a low temperature of 200 ° C. or lower, so that the polymerization reaction does not proceed sufficiently and the adhesion of the organic silica film as the precoat film is lowered. In some cases, it was a source of dust generation. Further, when growing an organic silica film having a porous structure and a rich carbon composition by the plasma polymerization method, the adhesion with the inner wall of the plasma reaction chamber is further deteriorated, and it is difficult to use the film itself as a precoat film. It was.

  Even when the techniques described in Patent Documents 1 to 3 are used for the above technical problem, when an organic silica film flew to a carbon composition is continuously grown by plasma polymerization, it is caused by the presence of carbon. The problem could not be solved.

  That is, in order to grow an organic silica film rich in carbon composition, particularly an organic silica film rich in carbon composition having a porous structure by plasma polymerization, 1) growth process of precoat film in plasma reaction chamber, 2) plasma A series of steps consisting of a growth process of an organic silica film by a polymerization method and 3) a plasma cleaning process of a plasma reaction chamber inner wall are necessary. In particular, the plasma cleaning process of the plasma reaction chamber wall of 3) is slow, The throughput was reduced.

On the other hand, in the present embodiment, in the manufacturing method in which an organic silica film rich in carbon composition (C / Si> 1) or an organic silica film having a porous structure is continuously grown on a semiconductor substrate by plasma polymerization. As the precoat film covering the plasma reaction chamber inner wall, a high oxygen-containing precoat film having a carbon composition lower than that of the organic silica film, for example, a silica film (SiO ₂ , C / Si = 0, O / Si = 2) is used. In the plasma cleaning step, the laminated film composed of the organic silica film rich in carbon composition formed on the inner wall of the plasma reaction chamber and the precoat film containing high oxygen content is removed. We have found that the plasma cleaning rate of the organic silica film rich in carbon composition grown on the plasma reaction chamber wall can be greatly increased by using the high oxygen content precoat film.

  Thereby, the cleaning time and the time required for a series of film forming steps can be shortened, that is, the throughput can be improved. Furthermore, by shortening the plasma cleaning time, it is possible to reduce the amount of gas used for cleaning, thereby reducing costs. In addition, the use of a high-oxygen-containing precoat film having a high film density and a low carbon composition that is rich in adhesiveness is effective for the generation of particles during the film formation and the prevention of metal contamination.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

  Examples are shown below, but the present invention is not limited to these Examples.

Example 1
In this embodiment, a silicon oxide film is used for pre-coating, an organic silica (SiOCH) film using trivinyltriisopropylcyclotrisiloxane (formula 2) is used for main film formation, and NF ₃ / Ar / O ₂ is used for cleaning. Was used as the cleaning gas.

First, in the pre-coating process, SiH ₄ and N ₂ O were supplied to the plasma reaction chamber 201 via a gas flow rate controller in order to deposit a silicon oxide film as a pre-coating film. The gas flow rates are 180 sccm and 2000 sccm, respectively.

  Subsequently, an RF power of 450 W was applied between the shower head 204 and the wafer stage 203 to deposit a silicon oxide film of about 200 nm on the inner wall of the plasma reaction chamber 201. The silicon oxide film has a carbon / silicon ratio of zero.

  After this pre-coating process was completed, a semiconductor substrate serving as a base was transferred from the wafer transfer chamber to the plasma reaction chamber 201 in order to perform the main film formation. At this time, the semiconductor substrate was placed on the silicon oxide film formed on the wafer stage 203 heated to 350 ° C.

  In this film forming process, trivinyltriisopropylcyclotrisiloxane was used as a raw material, and helium was used as a carrier gas, which was supplied to the plasma reaction chamber 201 via a vaporization controller. The supply rates were 1.4 g / min and 300 sccm, respectively. Subsequently, RF power 250 W is applied between the shower head 204 and the wafer stage 203 as in the pre-coating process. As a result, upon receiving thermal energy and plasma energy, the raw material undergoes a plasma polymerization reaction, and a 200 nm organic silica (SiOCH) film was deposited on the semiconductor substrate. The organic silica (SiOCH) film has a carbon / silicon ratio of 2.52. The relative dielectric constant was 2.53, and the mode value (peak) of the pore diameter distribution by the small angle X-ray scattering method was 0.44 nm. Naturally, an organic silica (SiOCH) film was deposited not only on the semiconductor substrate but also on the wafer stage and the shower head 204. However, no film was formed on most of the wafer stage 203 due to the presence of the semiconductor substrate.

  In this way, after completion of the main film formation, the semiconductor substrate is taken out from the plasma reaction chamber 201.

In the next cleaning process, NF ₃ , Ar, and O ₂ were used as the cleaning gas, and deposited in the plasma reaction chamber 201 by the pre-coating process and the main film-forming process. In this example, the supply amounts of the respective gases were NF ₃ = 1.2 SLM, Ar = 5.0 SLM, and O ₂ = 0.45 SLM. NF ₃ and Ar were supplied to the plasma reaction chamber 201 after being excited by a remote plasma source to which 3 kW of power was applied.

  The state of cleaning was confirmed by monitoring the emission of SiF with an emission spectrometer. It can be determined that the deposits in the plasma reaction chamber 201 have been removed by the absence of light emission from the decomposition product SiF. The results are shown in FIG. For comparison, FIG. 5b) shows a case where a film having a high carbon composition similar to that in the film forming process is used as the precoat film. For comparison, FIG. 5c) shows a case where oxygen is not added to the cleaning gas.

  When a silicon oxide film containing no carbon is used for the precoat film, it can be seen that the cleaning is completed in about 40 seconds. On the other hand, when an organic silica film rich in carbon composition is used in both the pre-coating process and the main film formation, a cleaning time of 130 seconds is required. By using a silicon oxide film as the pre-coating film, the cleaning speed is about 3 times faster. You can see that In both the pre-coating process and the main film formation, when an organic silica film rich in carbon composition is used, when cleaning is performed only with NF3 and Ar without adding oxygen as a cleaning gas, a cleaning time of 240 seconds is required. It can be seen that the cleaning rate is approximately doubled by adding oxygen. That is, it can be seen that speeding up cleaning using a high oxygen-containing film having a low carbon composition for the precoat film is more effective in speeding up than the effect of speeding up cleaning by adding oxygen.

This is because the silicon oxide film that does not partially contain carbon is exposed in the plasma reaction chamber 201, and the silicon oxide film is decomposed and removed by cleaning, thereby becoming an oxygen supply source. This is because the oxygen concentration in the cleaning gas is increased. Since this oxygen is supplied by decomposing the silicon oxide film by etching with NF ₃ , it is already in an active state at the time of supply, and the effect of extracting carbon in the organic silica (SiOCH) film is high, and organic silica (SiOCH ) Contributes to increasing the cleaning speed of the film. In addition, since it is supplied in the plasma reaction chamber, the supply path of the NF ₃ radical is not affected, and the activity of NF ₃ is not lowered.

On the other hand, when an organic silica (SiOCH) film rich in carbon composition is used for both the pre-coating process and the main film forming process, the film removed by cleaning is only the organic silica film rich in carbon composition. In this case, the fluorine of NF ₃ and the carbon of the organic silica film recombine during cleaning to form a CF-based deposit. Since NF ₃ cannot efficiently remove CF-based deposits, the cleaning speed decreases. Since the surface inside the plasma reaction chamber 201 is always covered with an organic silica film rich in carbon composition, it is considered that it took a very long time to remove the entire surface.

  As described above, when a film having a high carbon composition is used in this film forming process, the cleaning rate can be remarkably increased by using a film having a low carbon composition as the precoat film. This is a phenomenon peculiar to this combination. Even when an organic silica (SiOCH) film rich in carbon composition is used, very efficient cleaning more than simply increasing the amount of oxygen added is performed, resulting in a dramatic reduction in cleaning time. It is done.

(Example 2)
In this example, a high oxygen-containing film having a carbon composition lower than that of the organic silica film formed by the main film formation on the precoat, and an organic silica (SiOCH) film using trivinyltriisopropylcyclotrisiloxane for the main film formation. For cleaning, NF ₃ / Ar / O ₂ was used as a cleaning gas.

First, in the precoat process, trivinyltriisopropylcyclotrisiloxane, SiH ₄ and N ₂ O are plasmad via a gas flow controller in order to deposit a high oxygen content organic silica film having a low carbon composition as a precoat film. The reaction chamber 201 was supplied. The flow rate of trivinyltriisopropylcyclotrisiloxane was 1.0 g / min, the flow rate of He as a carrier gas was 1.0 SLM, and the flow rates of SiH ₄ and N ₂ O were 70 sccm and 700 sccm, respectively.

  Subsequently, an RF power of 250 W was applied between the shower head 204 and the wafer stage 203 to deposit a silicon oxide film of about 200 nm on the inner wall of the plasma reaction chamber 201. The carbon / silicon ratio of this organic silica film was 0.95.

  After the pre-coating process, in order to perform the main film formation, the semiconductor substrate as a base was transferred from the wafer transfer chamber to the plasma reaction chamber. At this time, the semiconductor substrate was placed on a silicon oxide film formed on a wafer stage heated to 350 ° C.

  In this film formation step, the same film formation as in Example 1 was performed. The carbon / silicon ratio of this organic silica (SiOCH) film was 2.5. The relative dielectric constant was 2.53, and the mode value (peak) of the pore diameter distribution by the small angle X-ray scattering method was 0.44 nm. After completion of the main film formation, the semiconductor substrate was taken out from the plasma reaction chamber.

In the cleaning process, NF ₃ , Ar, and O ₂ were used as cleaning gases, and the film deposited in the plasma reaction chamber by the pre-coating process and the main film-forming process was removed. Also in this example, the supply amounts of the respective gases were NF ₃ = 1.2 SLM, Ar = 5.0 SLM, and O ₂ = 0.45 SLM. NF ₃ and Ar were supplied to the plasma reaction chamber after being excited by a remote plasma source to which 3 kW of power was applied.

  The cleaning state was confirmed by monitoring the emission of SiF with an emission spectrometer. It can be determined that the deposit in the plasma reaction chamber has been removed by the absence of light emission from the decomposition product SiF. The results are shown in FIG.

  When a high oxygen content organic silica film having a low carbon composition (C / Si <1) is used as the precoat film, it can be seen that the cleaning is completed in about 42 seconds. The reason for this is that, as in Example 1, the high oxygen content organic silica film having a low carbon composition (C / Si <1) is partially exposed in the plasma reaction chamber. This is because the organic silica film is decomposed and removed by cleaning to serve as an oxygen supply source, effectively increasing the oxygen concentration in the cleaning gas.

  Therefore, when a film having a high carbon composition is used in this film forming process, it is confirmed that the cleaning rate can be remarkably increased by using a film having a low carbon composition as the precoat film. This is a phenomenon peculiar to this combination. Even when an organic silica (SiOCH) film rich in carbon composition is used, very efficient cleaning more than simply increasing the amount of oxygen added is performed, resulting in a dramatic reduction in cleaning time. It is done.

(Example 3)
In this embodiment, a silicon oxide film is used for pre-coating, an organic silica (SiOCH) film using trivinyltriisopropylcyclotrisiloxane is used for the main film formation, and NF ₃ / Ar / O ₂ is used as a cleaning gas for cleaning. Using.

  First, in the precoat process, a silicon oxide film having a thickness of about 200 nm was deposited on the inner wall of the plasma reaction chamber 201 in the same manner as in Example 1. The silicon oxide film has a carbon / silicon ratio of zero.

  After the pre-coating process is completed, a semiconductor substrate serving as a base is transferred from the wafer transfer chamber to the plasma reaction chamber 201 in order to perform main film formation. At this time, the semiconductor substrate is placed on the silicon oxide film formed on the wafer stage 203 heated to 350.degree.

In this film forming process, trivinyltriisopropylcyclotrisiloxane was used as a raw material, and helium was used as a carrier gas, which was supplied to the plasma reaction chamber 201 via a vaporization controller. The supply rates were 1.4 g / min and 500 sccm, respectively. At the same time, in this example, 80 sccm of N ₂ O was supplied as an additive gas.

  Subsequently, by applying RF power of 250 W between the shower head 204 and the wafer stage 203 as in the pre-coating process, the raw material receives a thermal energy and a plasma energy to cause a plasma polymerization reaction, resulting in a 200 nm on the semiconductor substrate. An organic silica (SiOCH) film was deposited. The organic silica (SiOCH) film has a carbon / silicon ratio of 2.32. The relative dielectric constant was 2.55, and the mode value (peak) of the hole diameter distribution by the small angle X-ray scattering method was 0.38 nm.

  As a matter of course, an organic silica (SiOCH) film is deposited not only on the semiconductor substrate but also on the wafer stage 203 and the shower head 204. However, the film is not formed on most of the wafer stage 203 due to the presence of the wafer. In this way, after completion of the main film formation, the semiconductor substrate is taken out from the plasma reaction chamber 201.

In the cleaning process, NF ₃ , Ar, and O ₂ were used as cleaning gases, and the film deposited in the plasma reaction chamber by the pre-coating process and the main film-forming process was removed. Also in this example, the supply amounts of the respective gases were NF ₃ = 1.2 SLM, Ar = 5.0 SLM, and O ₂ = 0.45 SLM. NF ₃ and Ar were supplied to the plasma reaction chamber after being excited by a remote plasma source to which 3 kW of power was applied.

  The cleaning state was confirmed by monitoring the emission of SiF with an emission spectrometer. It can be determined that the deposit in the plasma reaction chamber has been removed by the absence of light emission from the decomposition product SiF. The results are shown in FIG.

  As in Example 1, it can be seen that the cleaning is completed in about 40 seconds. The C / Si composition ratio of the organic silica film in this example is 2.3, and when a film having a high carbon composition is used in this film forming process, a film having a low carbon composition is used as the precoat film as in Example 1. By using it, the cleaning speed can be remarkably increased. This is a unique phenomenon newly developed by this combination. Even when an organic silica (SiOCH) film rich in carbon composition is used, very efficient cleaning more than simply increasing the amount of oxygen added is performed, resulting in a dramatic reduction in cleaning time. It is done.

Example 4
In this embodiment, a silicon oxide film is used for pre-coating, an organic silica (SiOCH) film using trivinyltriisopropylcyclotrisiloxane is used for the main film formation, and NF ₃ / Ar / O ₂ is used as a cleaning gas for cleaning. Using. In addition, cleaning is not performed every time one main film is formed, but cleaning is performed every time the main film is formed on three semiconductor substrates.

  First, in the pre-coating process, a silicon oxide film of about 200 nm was deposited on the inner wall of the plasma reaction chamber 201 as a pre-coating film as in Example 1. The silicon oxide film has a carbon / silicon ratio of zero.

  After the pre-coating process is completed, a semiconductor substrate serving as a base is transferred from the wafer transfer chamber to the plasma reaction chamber 201 in order to perform main film formation. At this time, the semiconductor substrate is placed on the silicon oxide film formed on the wafer stage 203 heated to 350.degree.

  Also in this film forming step, as in Example 1, a 200 nm organic silica (SiOCH) film was deposited on the semiconductor substrate. The organic silica (SiOCH) film has a carbon / silicon ratio of 2.52. The relative dielectric constant is 2.53, and the mode value (peak) of the hole diameter distribution by the small angle X-ray scattering method is 0.44 nm.

  As a matter of course, an organic silica (SiOCH) film is deposited not only on the semiconductor substrate but also on the wafer stage 203 and the shower head 204. However, no film is formed on most of the wafer stage 203 due to the presence of the wafer. In this way, after completion of the main film formation, the semiconductor substrate is taken out from the plasma reaction chamber 201.

  In this embodiment, the pre-coating is performed again without cleaning, and the main surface state in the plasma reaction chamber 201 is set to the initial state again. The same film formation is performed in the same manner. In this example, this process was repeated 3 times, and pre-coating was performed 3 times and main film formation was performed 3 times.

  After repeating the pre-coating / main film formation three times, cleaning was performed. The cleaning process was performed in the same manner as in Example 1.

  The cleaning state was confirmed by monitoring the emission of SiF with an emission spectrometer. It can be determined that the deposit in the plasma reaction chamber has been removed by the absence of light emission from the decomposition product SiF. The results are shown in Fig. 8f). As a comparison, FIG. 8g) shows a case where a film having a high carbon composition similar to that in the main film forming process is used in the precoating process.

  It can be seen that when the silicon oxide film containing no carbon is used for the precoat film, the cleaning is completed in about 112 seconds. By repeating the pre-coating three times and the main film formation, it takes about 2.8 times as long as the first embodiment. On the other hand, when an organic silica film rich in carbon composition is used in both the pre-coating process and the main film formation, a cleaning time of 383 seconds is required. By using a silicon oxide film as the pre-coating film, the cleaning speed is about It turns out that it has improved 3 times or more. It can be seen that the effect of increasing the cleaning speed by using a high oxygen content film having a low carbon composition for the precoat film is higher than that for each sheet.

  Therefore, when a film having a high carbon composition is used in the main film forming process, the cleaning rate can be remarkably increased by using a film having a low carbon composition as the precoat film. This is a unique phenomenon expressed by this combination. Even when an organic silica (SiOCH) film rich in carbon composition is used, very efficient cleaning more than simply increasing the amount of oxygen added is performed, resulting in a dramatic reduction in cleaning time. It is done.

  In this embodiment, cleaning is performed every 3 film formations. However, in the cleaning process for every 4 or more film formations, the quality of the organic silica film in the film formation is particularly good. Is not affected, and there is no problem if there is no generation of particles or metal contamination.

(Example 5)
An example of a semiconductor device manufactured using the above-described method will be described below with reference to the drawings. However, the same portions as those of the conventional example described above with respect to the present embodiment are denoted by the same names, and detailed description thereof is omitted.

  FIG. 9 is a cross-sectional view showing a semiconductor device including a capacitive element in a multilayer wiring according to one embodiment of the present invention. This semiconductor device is a combination of a logic circuit and a memory circuit. The memory circuit includes a memory peripheral circuit in addition to a memory element having a capacitor element. FIG. 9A is a cross-sectional view of the memory circuit region. FIG. 9B shows a typical sectional view of the logic circuit region.

  The semiconductor device according to the present embodiment includes a semiconductor substrate (silicon substrate 5), a multilayer wiring structure in which a plurality of wiring layers composed of wiring and insulating films are stacked, and a lower electrode 91 embedded in the multilayer wiring structure. , A capacitive insulating film 92, and a capacitive element 90 constituted by the upper electrode 93. Since the capacitive element 90 is provided over at least two wiring layers, a desired capacitance can be obtained by changing the number of wiring layers penetrated by the capacitive element 90 without changing the number of wiring layers in the multilayer wiring structure. it can. The multilayer wiring in the memory circuit area in which the capacitor element 90 is embedded and the multilayer wiring in the logic circuit area are formed in the same layer. For this reason, it is not necessary to newly provide a multilayer wiring in the logic circuit area. Thereby, a multilayer wiring structure can be provided compactly.

  Next, a method for manufacturing the semiconductor device of this embodiment will be briefly described. The semiconductor device of the present embodiment further includes a first diffusion layer (diffusion layer 7) formed near the surface of the silicon substrate 5 and a second diffusion layer (diffusion layer) formed near the surface of the silicon substrate 5. 7), a gate insulating film, and a gate electrode 8. In the semiconductor device of this embodiment, a field effect transistor (MOS transistor) 9 is constituted by the silicon substrate 5, the first diffusion layer, the second diffusion layer, the gate insulating film, and the gate electrode 8. is there. The gate insulating film of the MOS transistor 9 may be a high dielectric constant gate insulating film. For example, as the high dielectric constant gate insulating film, a high dielectric constant gate insulating film containing Hf such as silicon oxynitride such as SiON or Hf oxynitride can be used. Specifically, Hf oxide, Hf silicate, and a high dielectric constant insulating film into which nitrogen is introduced can be used. The gate insulating film may be a single layer or a multilayer composed of this kind.

  The gate electrode material is made of polysilicon or its upper surface layer covered with metal silicide such as Ni, Co, Ti, Pt. Furthermore, a metal gate electrode including Ti, Ta, Al or a conductive nitride thereof in a part of the gate electrode may be used. In particular, in the case of the metal gate electrode, not only the effect of improving the drive current of the transistor in the logic part but also the effect of reducing the resistance of the word line because the metal gate electrode constitutes the word line of the DRAM part. In addition, by combining with an eDRAM structure in which a capacitive element portion is embedded in a multilayer wiring layer, higher speed operation becomes possible.

  In FIG. 9, the bit line 19 is formed in the same layer simultaneously with the first layer wiring 15 in the logic circuit region, and there is no wiring layer only for the bit line. With the structure shown in this embodiment, the number of multilayer wiring layers can be used effectively.

  The contact interlayer insulating film 1 is made of a silicon oxide film, the contact plug 4 is made of tungsten, and the contact barrier metal film 3 is made of a laminated film of titanium nitride / titanium.

  In addition, the first layer interlayer insulating film 11 and the second layer interlayer insulating film 21 are formed by depositing an organic silica film by the method of the third embodiment, but may be formed by any one of the first to fourth embodiments. Good. The first layer wiring barrier metal film 13 is made of a tantalum / tantalum nitride laminated film, and the first layer wiring 15 is made of copper. The cap film on each wiring layer is made of a SiCN film.

  A method for forming the second layer wiring 25 will be briefly described. After forming the first layer wiring 15 and forming the cap film 20 of the first layer wiring, the organic silica film is formed as the interlayer insulating film 21 of the second layer. The organic silica (SiOCH) film has a carbon / silicon ratio of 2.32. The relative dielectric constant is 2.55, and the mode value (peak) of the hole diameter distribution by the small angle X-ray scattering method is 0.38 nm.

  Subsequently, a silicon oxide film (not shown) is formed as a mask for processing. Further, the opening of the second layer wiring is formed by a so-called dual damascene process using lithography and dry etching. At this time, a part of the opening includes a via hole for electrical connection to the first layer wiring 15. A second-layer wiring barrier metal film 23 is deposited in these openings by a sputtering method, and then copper to be a seed layer for copper plating is deposited. Further, copper is embedded by a plating method. The copper used here may contain an additive of a metal such as aluminum or silver. Excess barrier metal film and copper are removed by using a technique such as CMP so that the second layer wiring barrier metal film 23 and copper remain in the opening of the second layer wiring, thereby forming the second layer wiring 25. During this step, the silicon oxide film as a mask is removed and does not remain on the second-layer interlayer insulating film 21. Thereafter, the cap film 30 of the second layer wiring 25 is formed in the same manner as the first layer. Here, a silicon oxide film may be partially provided below the capacitive insulating film other than the opening of the capacitive element.

  In this embodiment, a single-layer insulating film is used for the interlayer insulating film and the cap film, but a laminated structure of a plurality of types of insulating films may be used. For example, the interlayer insulating film may be an organic silica film rich in carbon composition and another SiOCH film, and the cap film may be a laminated structure of a SiC film and a SiCN film. Moreover, the SiOCH film | membrane provided with Cu diffusion barrier property may be sufficient.

  Further, a third layer wiring 35 and a fourth layer wiring 45 are formed. As the formation method, the organic silica film was deposited by the method of Example 3 in the same manner as the second layer wiring 25. However, you may form into a film by the method in any one of Examples 1-4. Next, after the cap film 50 of the fourth layer wiring 45 is deposited, a hard mask insulating film 94 is formed. Further, a cylinder processing resist film (not shown) is formed by lithography. Here, the silicon oxide film is used as the hard mask insulating film 94, but a laminated structure with another insulating film may be used. Further, a multilayer structure such as an antireflection film may be provided between the resist film and the resist film. In any case, it is preferable that the insulating film has an effect of protecting the cap film 50 of the fourth layer wiring 45 in the process of forming the capacitive element. Specifically, in addition to the silicon oxide film, a silicon nitride film, a silicon oxynitride film, and the like can be given.

  Subsequently, a capacitor element opening is formed by dry etching. At this time, in order to prevent oxidation of the second layer wiring 25, the cap film 30 of the second layer wiring 25 is not etched. Further, the cylinder processing resist film is removed by ashing, and the cap film 30 of the second layer wiring 25 is etched back by dry etching in order to connect the lower electrode of the capacitive element to the second layer wiring 25 serving as a lower layer wiring. In the series of steps, the opening side wall is subjected to the plasma treatment or chemical treatment of the step, but the organic silica film, which is the interlayer insulation film of each layer, has a high carbon composition. The carbon contained in is extracted from the carbon that is distant from the silicon atom, and abrupt carbon extraction can be suppressed. As a result, characteristics and performance as an organic silica (SiOCH) film are maintained.

  Subsequently, a lower electrode film 91 to be a lower electrode of the capacitive element is formed, and a lower electrode structure is formed by lithography and dry etching. Subsequently, a capacitor insulating film 92 and an upper electrode film 93 are formed, and tungsten is further formed as a cylinder embedded metal film 99. An upper electrode processing resist film (not shown) is formed by lithography, and the cylinder embedded metal 99, the capacitor insulating film 92 and the upper electrode film 93 are etched by dry etching using the resist film as a mask.

Here, as materials used for the capacitor element 90, the upper electrode film 93 and the lower electrode film 91 include Ti, TiN, Ta, TaN, Ru, or a stacked structure thereof. Examples of the capacitive insulating film 92 include zirconium dioxide (ZrO ₂ ), zirconium aluminate (ZrAlOx), and a film obtained by adding lanthanoids such as Tb, Er, and Yb to zirconium dioxide.

  The hard mask insulating film 94 serves to protect the cap film existing in the lower layer of the hard mask film in the logic circuit portion and further the copper wiring in the lower layer in the ashing and etching processes described above. In particular, if the interlayer insulating film or cap film is not resistant to the etching process of oxygen plasma or capacitive film, without the hard mask film, the copper wiring in the logic circuit section will be oxidized and the resistance will increase and the reliability will deteriorate. Will occur, causing the performance deterioration and malfunction of the logic circuit section.

  Next, the upper electrode processing resist film is removed by ashing as in the lower electrode processing. Further, using the upper electrode as a mask, the hard mask insulating film 94 is etched back to expose the cap film 50 of the fourth layer wiring 45.

  Thereafter, a fifth interlayer insulating film 51 is formed. At this time, in the memory circuit portion, a step is generated between the memory circuit portion and the logic circuit portion due to the presence of the capacitive element 90, and this is flattened by a technique such as CMP. Thereafter, a hard mask insulating film used as a mask for forming the opening of the fifth layer wiring 55 is formed. Subsequent formation processes are performed in the same manner as the method for forming the second layer wiring 25, thereby forming the fifth layer wiring 55.

  At this time, in the memory circuit portion, the cylinder-embedded metal 99 functions as a stopper at the time of wiring groove processing, the groove depth is limited, and the upper capacitor wiring (the fifth capacitor formed in the memory circuit area is formed immediately above the groove depth. Layer wiring 55) is formed simultaneously. A structure in which the upper capacitor wiring is directly connected as the plate line wiring is obtained. This not only connects the capacitive elements as plate line wiring, but also realizes a reduction in electrical resistance between the elements. Further, the sixth layer wiring 65 is formed in the same manner, and then the upper layer wiring is formed to complete the semiconductor integrated circuit.

  In the present embodiment, the structure of the memory circuit portion and the logic circuit portion is a built-in type memory circuit portion and logic circuit portion in which the capacitor element 90 is embedded in a multilayer wiring structure. Does not change the design parameters. In other words, even if the memory circuit portion exists on the same semiconductor substrate, the structure and material of the multilayer wiring of the logic circuit portion is not changed at all, so it is completely compatible with the case of only the logic circuit portion. Design parameters can be used. In other words, in this mixed circuit chip, a high-speed memory function can be developed while maintaining the same logical operation capability as a logic circuit chip having only a normal logic circuit section.

(Example 6)
Example 6 will be described below. FIG. 10 is a cross-sectional view of the semiconductor device according to the sixth embodiment. This semiconductor device includes a magnetic tunnel junction element (MTJ) 100. FIG. 10A is a cross-sectional view of the magnetoresistive memory circuit region. FIG. 10B is a typical cross-sectional view of the logic circuit area.

The semiconductor device of this embodiment is formed on a semiconductor substrate (silicon substrate 5) and the silicon substrate 5, and wiring (third layer wiring 35, fourth layer wiring 45, fifth layer wiring 55, sixth layer wiring 65). And a wiring layer (third layer) composed of an insulating film (third layer insulating film 31, fourth layer insulating film 41, fifth layer insulating film 51, sixth layer insulating film 61) Wiring 35 and third layer interlayer insulating film 31, fourth layer wiring 45 and fourth layer interlayer insulating film 41, fifth layer wiring 55 and fifth layer interlayer insulating film 51, sixth layer wiring 65 and sixth layer wiring A multilayer wiring structure in which a plurality of interlayer insulating films 61) are stacked, and a magnetic tunnel junction element (MTJ) 100 embedded in the multilayer wiring structure. Furthermore, the semiconductor device of this embodiment is characterized in that the MTJ is provided in a so-called local wiring. Since MTJ has low heat resistance and its magnetization retention characteristics deteriorate when placed in a high temperature environment, an upper limit temperature is set for the process temperature of the wiring process. The organic silica film rich in carbon composition of the present invention can be formed from 200 ^° C. and can be formed without affecting the magnetization characteristics of the MTJ embedded in the multilayer wiring. is there.

  In this multilayer wiring structure, the wiring layers of the magnetoresistive memory circuit area and the logic circuit area are provided in the same layer. That is, the third layer wiring layer, fourth layer wiring layer, and fifth layer wiring layer in the memory circuit region and the third layer wiring layer, fourth layer wiring layer, and fifth layer wiring layer in the logic circuit region are in the same layer. Become.

  Next, a method for manufacturing the semiconductor device of this embodiment will be briefly described. In the semiconductor device of this embodiment, the MOS transistor 9 is formed on the silicon substrate 5 as in the fifth embodiment. The MOS transistor includes a diffusion layer 7, a gate electrode 8, and the like. The bit line 19 in the magnetoresistive memory region is formed in the same layer as the third layer wiring 35.

  In addition, in this embodiment, the first layer interlayer insulating film 11 and the second layer interlayer insulating film 21 are formed by depositing an organic silica film by the method of the third embodiment. A film may be formed.

  Next, an outline of a method for forming a magnetic tunnel junction element in the second layer wiring 25 will be described.

  After the first layer wiring 15 is formed and the cap film 20 of the first layer wiring made of SiCN film is formed, an organic silica film corresponding to the plug of the connecting portion between the magnetic tunnel junction element 100 and the first layer wiring 15 is formed. Form a film. Further, a silicon oxide film was formed using a hard mask. On the first layer wiring 15, an opening to be a junction with the magnetic tunnel junction element (MTJ) 100 is formed by lithography and dry etching, and after depositing a barrier metal and copper, CMP is performed to connect to the MTJ. Form a plug. Thereafter, the MTJ is formed in the second-layer interlayer insulating film 21 by repeating MTJ hard film formation, hard mask film formation, lithography and dry etching, and organic silica film deposition and etch back.

  Subsequently, a silicon oxide film (not shown) is formed as a mask for processing. Further, the opening of the second layer wiring is formed by a so-called dual damascene process using lithography and dry etching. At this time, a part of the opening includes a via hole for electrical connection to the first layer wiring 15 and a connection hole to the MTJ reference layer.

  A second-layer wiring barrier metal film 23 is deposited in these openings by a sputtering method, and then copper to be a seed layer for copper plating is deposited. Further, copper is embedded by a plating method. The copper used here may contain an additive of a metal such as aluminum or silver. Excess barrier metal film and copper are removed using a technique such as CMP so that the barrier metal film 23 and copper remain in the opening of the second layer wiring, thereby forming the second layer wiring 25. During this step, the silicon oxide film is removed and does not remain on the second interlayer insulating film 21. Thereafter, a cap film 30 of a second layer wiring made of a SiCN film is formed as in the first layer.

  In the subsequent steps, the openings of the third layer wiring to the sixth layer wiring can be formed by a so-called dual damascene process using lithography and dry etching in the same manner as the opening of the second layer wiring. The third-layer wiring barrier metal film 33, the fourth-layer wiring barrier metal film 43, the fifth-layer wiring barrier metal film 53, and the sixth-layer wiring barrier metal film 63 shown in FIG. The second layer wiring barrier metal film 23 can be formed in the same manner. The cap film 60 of the fifth layer wiring and the cap film 70 of the sixth layer wiring shown in FIG. 10 can be formed in the same manner as the cap film 30 of the second layer wiring.

  In this embodiment, a single-layer insulating film is used for the interlayer insulating film and the cap film, but a laminated structure of a plurality of types of insulating films may be used. For example, the interlayer insulating film may be an organic silica film rich in carbon composition and another SiOCH film, and the cap film may be a laminated structure of a SiC film and a SiCN film.

  Further, the third layer wiring 35, the fourth layer wiring 45 and the fifth layer wiring 55 are formed. As for the formation method of each interlayer insulating film, the organic silica film was deposited by the method of Example 3 in the same manner as the second layer wiring 25. The wiring formation process was performed in the same manner as the method after forming the opening of the second layer wiring. Further, the sixth layer wiring 65 is formed in the same manner, and then the upper layer wiring is formed to complete the semiconductor integrated circuit.

  In the present embodiment, the built-in type logic circuit unit is configured by using the built-in type memory circuit unit and logic circuit unit in which the MTJ 100 is embedded in a multilayer wiring structure. The design parameters do not change due to the presence of the MTJ 100. In other words, even if there is a built-in type memory circuit on the same semiconductor substrate, the structure and material of the multilayer wiring in the logic circuit does not change at all, so it is completely compatible with the case of only the logic circuit. It is possible to use design parameters that are reliable. In other words, in a mixed circuit chip composed of a memory circuit portion having a capacitive element and a logic circuit portion, a high-speed memory function is maintained while maintaining the same logical operation capability as a logic circuit chip having only a normal logic circuit portion. It can be expressed.

1 Contact interlayer insulating film 2 Etch stop film 3 Contact barrier metal film 4 Contact plug 5 Silicon substrate 6 Element isolation STI
7 Diffusion layer 8 Gate electrode 9 MOS transistor 11 First layer interlayer insulating film 13 First layer wiring Barrier metal film 15 First layer wiring 17 Row decoding wiring
18 Decode wiring 19 Bit line 20 Cap film 21 of first layer wiring Interlayer insulation film 23 of second layer Second layer wiring barrier metal film 25 Second layer wiring 30 Cap film 31 of second layer wiring Third layer interlayer Insulating film 33 Third layer wiring barrier metal film 35 Third layer wiring 40 Third layer wiring cap film 41 Fourth layer interlayer insulating film 43 Fourth layer wiring barrier metal film 45 Fourth layer wiring 50 Fourth layer wiring Cap film 51 Fifth layer interlayer insulating film 53 Fifth layer wiring barrier metal film 54 Hard mask insulating film 55 Fifth layer wiring 60 Fifth layer wiring cap film 61 Sixth layer interlayer insulating film 63 Sixth layer wiring barrier Metal film 65 Sixth layer wiring 70 Cap film 84 for sixth layer wiring Cylinder processing mask insulating film 88 Capacitor element opening A
89 Capacitor element opening B
90 capacitive element 91 lower electrode film 92 capacitive insulating film 93 upper electrode film 94 hard mask insulating film 98 capacitive element opening 99 cylinder embedded metal 100 magnetic tunnel junction element 201 plasma reaction chamber 203 wafer stage 204 shower head 206 ground line 207 exhaust Piping 208 Cooling trap 209 Vacuum pump 210 Substrate 211 Feed line 212 Matching controller 213 High-frequency power supply 214 Grounding line 215 Vaporizing material supply piping 216 Vaporizer 218 Gas flow rate controller 220 Valve 221 Valve 222 Exhaust valve 223 Liquid flow rate controller 224 Valve 225 Valve 226 Raw material Reservoir tank 227 Valve 228 Cleaning gas flow rate controller 229 Valve 230 Cleaning gas flow rate controller 231 Valve 232 Cleaning Gugasu flow controller 233 valve 234 additional gas flow controller 235 valve 236 additional gas flow controller 237 valve 238 additional gas flow controller 239 pipe

Claims (25)

A pre-coating step of coating a plasma reaction chamber wall with a pre-coating film;
A substrate processing step of growing an organic silica film having a silicon carbon composition ratio (C / Si) of 1 or more on the substrate;
A cleaning step of removing the organic silica film and the precoat film adhering to the plasma reaction chamber wall using plasma after taking out the substrate;
A method of manufacturing a semiconductor device, wherein a high oxygen content precoat film which is an organic silica film having at least a carbon content lower than that of the organic silica film is used as the precoat film.   The method of manufacturing a semiconductor device according to claim 1, wherein the organic silica film has a porous structure in which pores are dispersed.   In the substrate processing step, the organic silica film is grown by introducing a starting material gas obtained by vaporizing a cyclic organic silica compound having a cyclic siloxane structure into a rare gas plasma or a plasma containing a rare gas as a main component. A method for manufacturing a semiconductor device according to claim 1.   4. The semiconductor device according to claim 3, wherein both a side chain of a saturated hydrocarbon group and a side chain of an unsaturated hydrocarbon group are bonded to each silicon atom in the cyclic organic silica compound constituting the cyclic siloxane structure. Manufacturing method.   The method for manufacturing a semiconductor device according to claim 4, wherein the unsaturated hydrocarbon group has a vinyl group.   6. The method for manufacturing a semiconductor device according to claim 4, wherein the saturated hydrocarbon group contains two or more carbon atoms.   The method for manufacturing a semiconductor device according to claim 4, wherein the saturated hydrocarbon group includes three or more carbon atoms and has a branched structure. The method for manufacturing a semiconductor device according to claim 6, wherein the saturated hydrocarbon group containing two or more carbon atoms is an ethyl group (—CH ₂ CH ₃ ) or a propyl group (—CH ₂ CH ₂ CH ₃ ). The saturated hydrocarbon group containing three or more carbon atoms and having a branched structure is an isopropyl group (—CH (CH ₃ ) ₂ ) or a tertiary butyl group (—C (CH ₃ ) ₃ ). The manufacturing method of the semiconductor device of description.   The method for manufacturing a semiconductor device according to claim 3, wherein the cyclic organic silica compound has a 6-membered ring structure (ring number n = 3) composed of 3 silicons and 3 oxygens. The semiconductor device according to claim 3, wherein the cyclic organic silica compound is a “1,3,5-trivinyl-cyclotrisiloxane derivative” represented by the following formula (1). Manufacturing method.

(1) The semiconductor device according to claim 11, wherein the cyclic organic silica compound is “1,3,5-triisopropyl-1,3,5-trivinyl-cyclotrisiloxane” represented by the following formula (2). Method.

(2)   The method of manufacturing a semiconductor device according to claim 3, wherein the rare gas is helium.   The method for manufacturing a semiconductor device according to claim 3, wherein the plasma containing the rare gas as a main component is generated using a rare gas added with an oxidant gas as a main component. The method of manufacturing a semiconductor device according to claim 14, wherein the oxidant gas is N ₂ O, oxygen, carbon dioxide, alcohol, phenol, or a plurality of mixed gases selected from these.   16. The method of manufacturing a semiconductor device according to claim 15, wherein the alcohol is any one of methyl alcohol, ethyl alcohol, normal propyl alcohol, isopropyl alcohol, normal butyl alcohol, and isobutyl alcohol.   The method of manufacturing a semiconductor device according to claim 1, wherein the high oxygen content precoat film is a silicon oxide film.   The semiconductor according to any one of claims 3 to 16, wherein the high oxygen content precoat film is formed by introducing a starting material gas composed of the cyclic organic silica compound into the plasma by adding an oxidizing gas. Device manufacturing method.   The method for manufacturing a semiconductor device according to claim 1, wherein an etching gas mainly comprising a fluoride gas and argon is used in the cleaning step. The method of manufacturing a semiconductor device according to claim 19, wherein the fluoride gas contains nitrogen trifluoride (NF ₃ ). The method of manufacturing a semiconductor device according to claim 19, wherein the fluoride gas includes any one of C ₂ F ₆ , C ₃ F ₈ , C ₃ F ₆ , C ₄ F ₁₀ , C ₄ F ₈ , and C ₄ F _6. .   The method of manufacturing a semiconductor device according to claim 19, wherein an oxidizing gas is added to the etching gas in the cleaning step.   23. The method of manufacturing a semiconductor device according to claim 22, wherein the oxidant gas is oxygen.   24. A semiconductor device, wherein an organic silica film manufactured using the method for manufacturing a semiconductor device according to claim 1 is used as an interlayer insulating film. A semiconductor manufacturing apparatus for performing the method for manufacturing a semiconductor device according to claim 1,
A plasma reaction chamber having a mechanism for heating the substrate;
A film forming gas supply unit for gasifying a cyclic organic silica compound for growing an organic silica film rich in carbon composition and supplying the gas to a plasma reaction chamber;
A precoat source gas supply unit for supplying a silane gas and an oxidant gas for growing a precoat film to the plasma reaction chamber;
A cleaning gas supply unit for supplying a cleaning gas to the plasma reaction chamber;
An exhaust system;
A semiconductor manufacturing apparatus comprising:

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