JPH0945769A - Semiconductor device, and manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further reduce the dielectric constant more than a conventional silicon dioxide with fluorine added, and reduce the capacitance between wirings, and control signal delay, and improve high-speed operation, by making an interlayer insulating film contain not only the composition where one F atom is coupled with one Si atom but also the composition where two atoms are coupled with it and the composition where three atoms are coupled with it. SOLUTION: This semiconductor device is equipped with at least a plurality of elements and an interlayer insulating film for electrically insulating a plurality of wirings being connected severally to these elements and also are arranged in parallel and are made multilayer. In such a semiconductor device, the interlayer insulating film is made of an SiO2 film containing Si, O, and F at least, and besides the composition of the SiO2 film has structure 2 including Si atoms coupled in common through O atoms. Furthermore, the structure contains not only the composition 3 where one F atom is coupled with one Si atom but also the composition 4 where two F atoms are coupled with one Si atom and the composition where three F atoms are coupled with one Si atom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating film for isolating wiring, and more particularly to a semiconductor device having an insulating film containing fluorine and a method of manufacturing the same.

[0002]

2. Description of the Related Art In a semiconductor device, an insulating film is used for electrically insulating between wirings of elements. Conventionally, as this insulating film, thermally oxidized silicon dioxide (Si
O ₂ ) film or silane or tetraethoxysilane (TE
Chemical vapor deposition (CVD-Chemical Vapor Deposition) under reduced pressure or normal pressure using a gas such as OS) as a raw material
A silicon dioxide (SiO ₂ ) film formed by using is mainly used. In particular, among metal wirings, insulation between aluminum (Al) wirings can be formed at a low temperature of about 400 ° C. Therefore, it is possible to form silicon dioxide by plasma CVD using TEOS and oxygen (O ₂ ) or ozone (O ₃ ). A SiO ₂ ) film is used.

In recent years, the delay of signal transmission has become a problem with the high integration and high speed of semiconductor elements. This is because the inter-wiring capacitance (C) increases with the miniaturization of elements and the inter-wiring capacitance (C) increases, and the wiring resistance (R) increases due to the reduction of the wiring cross-sectional area, which increases the time constant of signal transmission. (RC delay) RC delay hinders high-speed operation of semiconductor devices, especially logic devices and high-speed SRAM (St
atic Random Access Memory) is the main cause of hindering performance improvement. As a countermeasure, aluminum (A
l) Copper (Cu) or silver (Ag) having a lower specific resistance than that is used as a wiring material to reduce the wiring resistance, and the inter-wiring capacitance is reduced by lowering the relative dielectric constant of the insulating film interposed between the wirings. Two points are important.

The relative permittivity of a silicon dioxide (SiO ₂ ) film formed by the conventional plasma CVD method is 4.0 to 4.0.
5.0 and 3.9 of thermally oxidized silicon dioxide (SiO2) film
It is known that a large value is also shown for. Therefore, in order to reduce the relative dielectric constant, silicon dioxide (Si
The introduction of fluorine (F) into the O2) film has been studied, and it has been reported that the relative dielectric constant is reduced.

Regarding the method of introducing fluorine (F), fluorine (F) ion implantation method, silicon fluoride [SiF (O
C ₂ H ₅ ) ₃ ] and water (H ₂ O) are used for the CVD method, and a boric acid aqueous solution is added to a supersaturated aqueous solution of silicon hydrofluoride (H ₂ SiF ₆ ) to add silicon dioxide (SiO ₂ ) in a liquid phase. Known is a method of projecting, a plasma CVD method using a gas (CF ₄ , NF _3, etc.) containing TEOS and oxygen (O ₂ ) and fluorine (F). Silicon dioxide (SiO
₂ ) Regarding the state of fluorine (F) in the film, the formation of Si-F bond has been confirmed by infrared absorption spectrum measurement, and it has been incorporated as F2 molecule or FOx molecule (x = 2, 3). It is said that things also exist.
In addition, with the introduction of fluorine (F), silicon dioxide (Si
It has also been found that the density of the O ₂ ) film is reduced. The effect of fluorine (F) on the reduction of the relative permittivity of silicon dioxide (SiO ₂ ) is generally because the polarizability of fluorine (F) atoms or fluorine (F) ions is smaller than that of oxygen. It is considered that this is because the polarizability is reduced as a whole by the amount of F) replacing oxygen. More specifically, since the 2p electron energy level of fluorine (F) is deeper than that of the 2p electron of oxygen (O), the oxygen (O) 2p isolation that constitutes the upper part of the valence band of silicon dioxide (SiO ₂ ) is isolated. It is theoretically known that the density of states of the electron pair level is reduced, and instead, a deeper fluorine (F) 2p lone electron pair level is formed.

[0006]

As described above, the effectiveness of fluorine (F) in reducing the relative dielectric constant of silicon dioxide (SiO ₂ ) has been confirmed. However,
The relationship between the concentration of fluorine (F) in the insulating film, the state of fluorine (F), the film density, and the relative dielectric constant has not been clarified. For this reason, control of the concentration of fluorine (F) in the silicon dioxide (SiO ₂ ) film has been studied, but control of even the bonding state of (F) has not been studied.

An object of the present invention is to provide a method for further reducing the relative permittivity of silicon dioxide (SiO ₂ ) by controlling the bonding state of fluorine (F) in the silicon dioxide (SiO ₂ ) film. To do.

[0008]

To this end, in the present invention, at least silicon (Si), oxygen (O), fluorine (F) is used as an insulating film for electrically insulating between wirings which form a semiconductor device. ) Containing silicon dioxide (Si
In forming the O ₂ ) film, one atom of silicon (Si) contains not only one atom of fluorine (F) but also silicon (Si) atoms bonded by two or three atoms.

In the present invention, as a raw material gas, an organic silane gas, an oxidizing gas and a compound gas containing F as one of the constituent elements; an inorganic silane gas, an oxidizing gas and a compound gas containing F as one of the constituent elements; an oxidizing agent. Gas and F
An organic silane gas containing 1 as a constituent element; an oxidant gas and an inorganic silane gas containing F as a constituent element; or an organic silane gas containing F and O as constituent elements is used.

Examples of the compound gas containing fluorine (F) as one of the constituent elements include nitrogen trifluoride (NF ₃ ), tetrafluoromethane (tetrafluoromethane-CF ₄ ), and hexafluoroethane (hexafluoro). ethane -C ₂ F _6), chlorine trifluoride (C1F _3), tetrafluoride silane (tetrafluoroethylene silane -
SiF _4), and the like. As an example of the organic silane gas containing fluorine (F) as one of the constituent elements, SiF (O
C ₂ H ₅ ) ₃ , SiF ₂ (OC ₂ H ₅ ) ₂ , SiF
₃ (OC ₂ H ₅ ) and the like. These gases are
It is also possible to use an organic silane gas containing fluorine (F) and oxygen (O) as constituent elements without an oxidant gas. Examples of the inorganic silane gas containing fluorine (F) as one of the constituent elements include SiH ₃ F, SiH ₂ F ₂ and SiHF.
_{3 and the} like. In addition, TE is used as the organic silane gas.
OS, HSi (OC ₂ H ₅ ) ₃ , H ₂ Si (OC
₄ H ₉ ) _{2 and the} like. Examples of the inorganic silane gas include SiH ₄ and Si ₂ H ₆ . Examples of the oxidant gas include O ₂ and N ₂ O.

Further, the semiconductor device according to the present invention as a detailed structure is for electrically insulating a plurality of elements and a plurality of wirings connected to these elements and arranged in parallel and multilayered. In at least an interlayer insulating film, the interlayer insulating film is formed of a silicon dioxide (SiO2) film containing at least silicon (Si), oxygen (O), and fluorine (F), and the composition of the silicon dioxide film. Has a structure containing a silicon atom covalently bonded via an oxygen (O) atom, and the structure has one fluorine (F) atom per one silicon (Si) atom.
Not only the composition in which atoms are bonded, but one silicon (S
i) a composition in which two fluorine (F) atoms are bonded to one atom, and three fluorine (F) atoms in one silicon (Si) atom
It is characterized by including a composition in which atoms are bonded.

Further, in the semiconductor device having the above structure, in order to suppress absorption of moisture in the atmosphere due to fluorine contained in the interlayer insulating film, a shield insulation having a hygroscopic property smaller than that of the interlayer insulating film is provided. A film is further provided, and the interlayer insulating film and the shielding insulating film have a laminated structure.

Further, in the above structure, the shielding insulating film having a low hygroscopic property is a silicon dioxide (SiO ₂ ) film containing no fluorine (F).

In the method of manufacturing a semiconductor device according to the present invention, a plurality of elements and a plurality of wirings connected to these elements and arranged in parallel and multilayered are electrically insulated. At least an interlayer insulating film, the interlayer insulating film containing at least silicon (Si), oxygen (O) and fluorine (F) silicon dioxide (SiO ₂ ).
The silicon dioxide film is formed by a film, and the composition of the silicon dioxide film has a structure containing silicon atoms covalently bonded via oxygen (O) atoms, and the structure has one fluorine atom for each silicon (Si) atom. Not only the composition in which the (F) atoms are bonded, but the composition in which two fluorine (F) atoms are bonded to one silicon (Si) atom, and the three fluorine (F) atoms are bonded to one silicon (Si) atom A method of manufacturing a semiconductor device including a combined composition, comprising: a first step of placing a semiconductor substrate on which elements are formed in a container capable of maintaining a constant sealed state and heating the semiconductor substrate to a predetermined temperature; A raw material gas containing at least silicon (Si), oxygen (O), and fluorine (F) is introduced into the container in which the heated semiconductor substrate is installed at a predetermined flow rate, and the inside of the container is A second step and, the by applying a predetermined voltage to electrodes is opposed to the semiconductor substrate subjected to a plasma discharge of a predetermined equivalent fluorine holding a constant pressure (F)
And a third step of depositing a silicon dioxide (SiO ₂ ) film containing a metal wiring film on the silicon dioxide film and patterning a first layer of a predetermined width, length and thickness. A fourth step of forming metal wiring in a predetermined column, and fifth to mth steps of forming metal wiring of second to n-th layers by repeating the first to fourth steps. There is.

Further, in the manufacturing method having the above structure, at least oxygen (O) is formed after the step of forming each layer of the interlayer insulating film containing fluorine (F) formed in multiple layers.
₂ ) A step of introducing a raw material gas containing no fluorine (F) at a predetermined flow rate to form a silicon dioxide (SiO ₂ ) film containing no fluorine (F) is provided for each layer. It is characterized by being.

Further, the source gas is a compound gas containing fluorine (F) as a constituent element, an organic silane gas and an oxidizing gas; a compound gas containing fluorine (F) as a constituent element, an inorganic silane gas and an oxidizing gas; fluorine. Any one of an organic silane gas containing (F) as a constituent element and an oxidant gas; and an organic silane gas containing fluorine (F) and oxygen (O) as a constituent element.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a semiconductor device and a method of manufacturing a semiconductor device according to the present invention will be described below.

FIG. 1 is a schematic diagram for explaining the basic concept of the present invention, and shows an amorphous structure 1 of an interlayer insulating film of silicon dioxide (SiO ₂ ). The amorphous is neither a molecule nor a crystal. The silicon dioxide film formed by the method for manufacturing a semiconductor device including the present invention has a tetrahedral structure in which four bonds extend centering on silicon (Si) in the directions of oxygen atoms at the vertices of a triangular pyramid. The structure in which these vertices are connected is an amorphous structure. In FIG. 1, a circle centering on silicon (Si) schematically illustrates the tetrahedral structure in plan view, and this structure is hereinafter referred to as a “molecule”.

In the figure, each molecule is covalently bonded via an oxygen atom, and a molecule 2 in which all four bonds of one silicon (Si) atom are bonded to the oxygen (O) atom 2
And a molecule 3 in which three of the four bonds are bonded to the oxygen atom and one is bonded to the fluorine atom, and two of the four bonds are bonded to the oxygen atom and two are bonded to the fluorine atom. It includes a bonded molecule 4 and a molecule 5 in which one of the four bonds is bonded to an oxygen atom and three are bonded to a fluorine atom.

Next, a first embodiment of the semiconductor device according to the present invention will be described with reference to FIGS.
FIG. 2 shows a change in one-electron energy level associated with a change in the number of fluorine (F) atoms bonded to one silicon (Si) atom, which is calculated by an ab initio molecular orbital method using a cluster model. The result of having obtained the density of states is shown. First,
From the result of the model cluster representing silicon dioxide (SiO ₂ ), it is confirmed that the upper part of the valence band of silicon dioxide (SiO ₂ ) is composed of the O2p lone electron pair level. Next, as a result of the model cluster in which one or two of the oxygen atoms (O) of the SiO2 model cluster were replaced by fluorine atoms (F), the change in the upper part of the valence band was observed as the change of the O2p lone electron pair level. It can be seen that the density of states decreases and, in return, a lower F2p lone electron pair level is formed and the O2p lone electron pair level near the top of the valence band undergoes a blue shift. Further, it is understood that this blue shift is larger in the model cluster in which two fluorine (F) are substituted than in the model cluster in which one fluorine (F) is substituted. The shift of the highest occupied level shows a potential shift of about 0.43 eV when only one fluorine atom (F) is replaced, and a shift of about 0.75 eV when two fluorine atoms (F) are replaced. Became.

FIG. 3 shows fluorine (F) -doped silicon dioxide (SiO ₂ ) calculated using the result of the density of states of FIG.
The calculation result of the fluorine (F) concentration dependence of the electronic polarizability α of the film is shown. Here, since the average molecular weight M of the fluorine (F) -added silicon dioxide (SiO ₂ ) film also depends on the fluorine (F) concentration, α is obtained by dividing the electronic polarizability by the average molecular weight.
The dependence of / M on the concentration of fluorine (F) was shown. Fluorine (F)
It can be seen that the addition decreases α / M, and α / M decreases almost in proportion to the increase in the fluorine (F) concentration. In addition, 1
Compared to the case where the interlayer insulating film includes only a molecular structure in which one fluorine atom (F) is bonded to one silicon atom (Si), two fluorine atoms (F) are added to one silicon atom (Si). It is understood that the decrease rate of α / M for the same fluorine (F) concentration is larger when the interlayer insulating film includes a molecular structure in which) is bonded.

FIG. 4 uses the results of FIG. 3 for fluorine (F).
The result of calculation of the fluorine (F) concentration dependence of the square of the refractive index n of the added silicon dioxide (SiO ₂ ) film is shown.
The dielectric constant of a silicon dioxide (SiO ₂ ) film is determined by the sum of the contributions of ionic polarization and electronic polarization. The contribution of ionic polarization to the permittivity is effective in the lower frequency region than the infrared absorption region. On the higher frequency side than the infrared absorption region, it may be considered that only the contribution of electronic polarization is almost given, and ε = n ^{2 for the} dielectric constant and the refractive index n.
There is a relationship. Fluorine (F) added is decreased the n ^2, n ^2, it is seen to decrease substantially in proportion to the increase of the fluorine (F) concentration. Further, as compared with the case where only one atom of a fluorine atom (F) is bonded to each silicon atom (Si), only the molecular structure of a state where two fluorine atoms (F) are bonded is included. It can be seen that in the case, the decrease rate of n2, that is, the dielectric constant ε, is larger for the same fluorine (F) concentration.

From the above results, silicon dioxide (SiO 2
₂ ) When fluorine (F) is taken into the network, it is better to form one molecule of silicon (Si) by combining two or more fluorine atoms (F) with one silicon atom (Si) to form a molecule. It was shown that the effect of reducing the relative permittivity is greater than that in the case where only one silicon atom in which fluorine (F) is bonded by one atom is included.

Next, the basic concept of the method for manufacturing a semiconductor device according to the second embodiment of the present invention will be described with reference to the flow chart shown in FIG. In FIG. 5, the method for manufacturing a semiconductor device according to this embodiment is for manufacturing a semiconductor device having the above-described configuration, and includes the following steps.

As shown in FIG. 5, the first step ST1
In step 1, the semiconductor substrate on which the element is formed is placed in a container capable of maintaining a constant sealed state and heated to a predetermined temperature. Then, in the second step ST2, in the accommodation container in which the heated semiconductor substrate is installed,
A source gas containing at least silicon (Si), oxygen (O), and fluorine (F) is introduced at a predetermined flow rate, and the inside of the container is maintained at a predetermined pressure. Third step S
At T3, a predetermined voltage is applied to the electrode facing the semiconductor substrate to perform plasma discharge, and a silicon dioxide (SiO ₂ ) film containing a predetermined equivalent amount of fluorine (F) is deposited. In a fourth step ST4, a metal wiring film is formed on the silicon dioxide film, and patterned to form a first layer of metal wiring having a predetermined width, a predetermined length and a predetermined thickness in a first layer.

First to fourth steps ST1 to S
Due to T4, 2 in one silicon atom in the molecular structure
A silicon dioxide film having a composition in which three to three fluorine atoms are bonded is formed, but in order to suppress the property of the fluorine-added film having a strong hygroscopic property, a moisture absorption process such as the fifth step ST5 is optionally performed as a subsequent step. The blocking film may be formed on the surface side of the silicon dioxide film containing fluorine. That is, in the fifth step ST5, at least oxygen (O2) is contained and fluorine (F) is contained after the fourth step ST4 of forming each layer of the interlayer insulating film containing fluorine (F) formed in multiple layers. A raw material gas not containing is introduced at a predetermined flow rate to form a silicon dioxide (SiO ₂ ) film containing no fluorine (F).

When the first to fourth steps ST1 to ST4 or the fifth step ST5 are completed, the first-layer interlayer insulating film is formed. As described above, the metal wiring is formed in multiple layers. Therefore, in order to form the second to n-th layer metal wirings, in the next sixth step ST6, it is judged whether or not the predetermined layer metal wirings and the interlayer insulating film of silicon dioxide are formed. To be done. When it is determined in the sixth step ST6 that the metal wiring and the interlayer insulating film of each predetermined layer are formed, all the steps of the method for manufacturing a semiconductor device are ended, but if all the layers are formed, When it is determined that the process has not been completed, the process returns to the first step ST1 again and the above steps are repeated.

FIG. 6 is an explanatory diagram of a third embodiment showing a method of forming an insulating film between multi-layered wirings using SiF ₂ (OC ₂ H ₅ ) and O ₂ as source gases. In the method of manufacturing the semiconductor device according to the third embodiment, the semiconductor substrate 41 on which the element is formed is set on the electrode 42 and heated to 440 ° C. by the resistance heater. TEOS as raw material gas
Is 50 cm ³ / min, O 2 is 500 cm ³ / min,
SiF ₂ (OC ₂ H ₅ ) ₂ 0-500 cm ³ / min
Are simultaneously introduced into the film forming chamber 43 at a flow rate of 3 to maintain the pressure in the chamber at 133 Pa. 13.56 MHz for the electrode 44 facing the semiconductor substrate 41
RF power is applied to start discharge. FIG.
As shown in (a), 500 nm fluorine (F) -added silicon dioxide (SiO ₂ ) on the semiconductor substrate 41.
The film 45 is deposited.

Next, as shown in FIG. 6B, an aluminum (Al) film is formed by DC magnetron sputtering and patterned to form a first layer of aluminum having a wiring width of 500 nm and a wiring thickness of 400 nm. (Al) wiring 46 is formed. After that, as shown in FIG.
An 800 nm thick F-added silicon dioxide (SiO ₂ ) film 47 is formed by the same film forming method as described above. Further, similarly to the above, a 400 nm aluminum (Al) film is formed and patterned to form a second layer of aluminum (Al).
After forming the wiring 48, the same film forming method as described above is applied to 800n.
m of fluorine (F) added silicon dioxide (SiO
₂ ) Form the film 49.

In FIG. 7, the fluorine (F) film formed with the flow rate of SiF ₂ (OC ₂ H ₅ ) ₂ set to 150 cm ³ / min.
Adding silicon dioxide showing the infrared absorption spectrum of (SiO ₂₎ film. This infrared absorption spectrum shows about 1080c
In addition to the absorption peaks attributed to the normal vibrational mode peculiar to SiO _{2 at} m-1, about 800 cm-1, and about 450 cm-1, about 98
Absorption peaks attributed to SiF ₃ bond and SiF ₂ bond at 5 cm -1 and about 950 cm -1 and Si at about 935 cm -1.
An absorption peak attributed to the F bond was observed. From this result, it can be seen that the F-added SiO2 film efficiently containing Si atoms in which two or more F atoms are bonded per Si atom is formed. The F atom concentration in this F-added SiO ₂ film was about 10 at%, the refractive index was 1.41 and the relative dielectric constant was 3.3. By the way, F-added Si by the conventional method
In the O ₂ film, when the F atom concentration is about 10 at%, the refractive index is 1.
The 43 dielectric constant was 3.4.

The semiconductor device manufactured by the method for manufacturing a semiconductor device according to the third embodiment absorbs moisture as much as fluorine (F) is contained in the interlayer insulating film as compared with the conventional semiconductor device. As shown in FIG. 8, a method of manufacturing a semiconductor device according to the fourth embodiment is conceivable in which a shielding film made of silicon dioxide containing no fluorine is formed.

First, referring to FIGS. 9 and 10, the relationship between the relative dielectric constant and the fluorine (F) concentration in the case where the silicon dioxide insulating film contains fluorine and the case where it does not contain fluorine, and the fluorine (F) concentration and the hygroscopicity. The relationship will be briefly explained. As is clear from FIG. 9, the contribution of electronic polarization and ionic polarization is greater in the case where two fluorine atoms are bonded than in the case where one fluorine atom is bonded to one silicon atom. The combined decrease in the relative dielectric constant is seen. Further, as shown in FIG. 10, it can be seen that the moisture absorption resistance is rapidly deteriorated in the film containing a large amount of fluorine. Therefore, in order to prevent this moisture absorption, a process such as forming a shielding film and its configuration are required.

FIG. 8 shows SiO ₂ with fluorine (F) added.
An explanation will be given of a method of forming an insulating film between multi-layered wirings according to a fourth embodiment of the present invention, in which a film and a SiO ₂ film not containing F are laminated to suppress moisture absorption of the insulating film layer. It is a figure. A semiconductor device manufacturing method embodying the present invention is
As shown in FIG. 8A, a semiconductor substrate 6 on which elements are formed
Boron phosphorus glass film (BPSG) 62 of 800n on top
m, and then a 400 nm A1 film is formed by a sputtering method and then patterned to form a first layer of A1 film.
The wiring 63 is formed.

Next, as shown in FIG. 8B, TEOS and O ₂ are used as source gases, and a SiO ₂ film 64 without F is formed to a thickness of 100 nm. On top of that, TEOS, O ₂ and Si were used as source gases as in Example 1.
With _{F2 (OC 2 H 5) 2} , to 500nm deposited SiO ₂ film 65 which is F added. Then, as a source gas, T
EOS and O ₂ with no F added SiO ₂
The film 66 is formed to 100 nm.

Next, as shown in FIG. 8C, a resist is applied, exposed and developed, and then a via hole 67 is formed in the insulating film on the aluminum (Al) wiring 63 by dry etching. As shown in FIG. 8D, the via hole 67 is filled with tungsten 68 by combining the selective CVD method or the non-selective CVD method using WF ₆ and SiH 4 as the source gas with the chemical mechanical polishing or the resist etch back. Then 400 nm
After the A1 film is formed by the sputtering method, patterning is performed to form the second layer A1 wiring 69. Then, F
An SiO ₂ film 610 without addition, a SiO ₂ film 611 with F added 500 nm, and a SiO ₂ film 612 without F added 100 nm are sequentially formed.

The silicon dioxide (SiO ₂ ) film to which fluorine (F) is not added has a lower hygroscopic property than the silicon dioxide (SiO ₂ ) film to which fluorine (F) is added.
Therefore, in the semiconductor device of FIG. 8D, it is possible to control the moisture absorption of the insulating film layer and suppress the decrease in reliability represented by the increase of the dielectric constant and the corrosion of the wiring.

In the above embodiment of the present invention, TEOS, O 2 and SiF ₂ are used as raw material gases.
(OC ₂ H ₅ ) ₂ was used, but it is not limited to this. The compound gas containing F as one of the constituent elements includes NF ₃ , CF ₄ , C ₂ F ₆ ClF ₃ and SiF ₄ , and the organic silane gas containing F as one of the constituent elements includes SiF (OC ₂ H ₅ ) ₃ , SiF ₂ (OC ₂ H ₅ )
₂ , SiF ₃ (OC ₂ H ₅ ) or the like may be used. These gases can be used as an organic silane gas containing F and O as constituent elements without an oxidant gas.
The inorganic silane gas containing F as one of the constituent elements is S
iH ₃ F, and the like may be used SiH ₂ F _2, SiHF _3. As the organic silane gas, TEOS, HSi (OC _{2
H 5) 3, H 2 Si} (OC 4 H 9) may be used ₂ or the like. As the inorganic silane gas, SiH ₄ , Si ₂ H ₆ or the like may be used. O ₂ and N ₂ O are used as the oxidizing gas.
Etc. may be used.

Further, in the above-described embodiment according to the present invention, high-purity aluminum (A
1) was used, but it is not limited thereto. For example, other alloys containing aluminum (Al) as a main component may be used, or copper (Cu), silver (Ag), gold (Au), nickel (Ni), palladium (Pd), or platinum (P).
An alloy using any one of t) or one or more of these elements as a main wiring material may be used.

[0039]

EFFECT OF THE INVENTION Interlayer insulating silicon dioxide (SiO2) formed by the method of manufacturing a semiconductor device according to the present invention.
The film is a silicon (Si) atom in which not only one atom but also two or three atoms of fluorine (F) are bonded to one atom of silicon (Si) when fluorine (F) is taken into the network of silicon dioxide (SiO2). Therefore, one atom of silicon (Si) contains one fluorine (F).
The effect of reducing the relative permittivity by fluorine (F) is greater than that in the case where only the molecular structure in the atomically bonded state is included. Therefore, it can have a lower relative permittivity than a conventional silicon dioxide (SiO ₂ ) film to which fluorine (F) is added. Therefore, the capacitance between wirings can be reduced and the signal delay can be controlled to increase the device speed. Motion can be achieved.

Further, by using the present invention, the bonding state of fluorine (F) can be controlled so as to effectively reduce the relative permittivity of the insulating film containing silicon dioxide (SiO ₂ ) as a main component, and therefore silicon dioxide can be controlled. The relative dielectric constant of (SiO ₂ ) is the same as that of conventional silicon dioxide (S) added with fluorine (F).
The signal delay can be suppressed by further reducing the capacitance of the semiconductor device from that of SiO ₂ ) and reducing the inter-wiring capacitance, and the high-speed operation performance of the semiconductor device can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the basic concept of a semiconductor device according to the present invention.

FIG. 2 is a fluorine (F) bonded to a silicon (Si) 1 atom in the semiconductor device according to the first embodiment of the present invention.
Explanatory drawing which shows the change of density of states with the change of the number of atoms.

FIG. 3 is an explanatory diagram showing a fluorine (F) concentration dependency of an electronic polarizability α of a silicon dioxide (SiO 2) film to which fluorine (F) is added according to the first embodiment of the present invention.

FIG. 4 is an F-doped Si according to the first embodiment of the present invention.
Explanatory drawing showing the F concentration dependence of the square of the refractive index n of the O2 film.

FIG. 5 is a flowchart showing each step of the method for manufacturing a semiconductor device according to the second embodiment of the present invention.

FIG. 6 is an explanatory view showing a method for forming an insulating film between multi-layer wirings in the method for manufacturing a semiconductor device according to the third embodiment of the present invention.

FIG. 7 is an explanatory diagram showing a change in infrared absorption spectrum according to a change in the number of fluorine (F) atoms bonded to one silicon (Si) atom in the third embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a method of forming an insulating film between multilayer interconnections in the method of manufacturing a semiconductor device according to the fourth embodiment of the present invention.

FIG. 9 is a characteristic diagram showing the relationship between relative dielectric constant and fluorine (F) concentration for explaining the fourth embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between a fluorine (F) concentration and a moisture absorption amount in order to explain a fourth embodiment.

[Explanation of symbols]

41 Semiconductor substrate 42 on which element is formed 42, 44 Electrode 43 Film formation chamber 45, 47, 49 F SiO 2 film 46, 48 Al wiring 410 Gas introduction system 411 Exhaust system 412 High frequency power supply 61 Semiconductor substrate on which element is formed 62 BPSG Film 63,69 Al wiring 64,66,610,612 F undoped Si
O2 film 65,611 F-added SiO2 film 67 Via (through) hole 68 Tungsten

Claims (6)

[Claims] 1. A semiconductor device comprising at least a plurality of elements and an interlayer insulating film for electrically insulating between a plurality of wirings which are respectively connected to these elements and arranged in parallel and multilayered. The interlayer insulating film is made of silicon dioxide (Si) containing at least silicon (Si), oxygen (O), and fluorine (F).
O ₂ ) film, and the composition of the silicon dioxide film has a structure containing silicon atoms covalently bonded via oxygen (O) atoms, and the structure has a structure of one silicon (Si) atom. Not only the composition in which one fluorine (F) atom is bonded, but also the composition in which two fluorine (F) atoms are bonded to one silicon (Si) atom, and three fluorine (F) in one silicon (Si) atom ) A semiconductor device including a composition in which atoms are bonded. 2. The semiconductor device further comprises a shield insulating film having a lower hygroscopicity than the interlayer insulating film in order to suppress absorption of moisture in the atmosphere due to fluorine contained in the interlayer insulating film. The semiconductor device according to claim 1, wherein the interlayer insulating film and the shield insulating film have a laminated structure. 3. The semiconductor device according to claim 2, wherein the shielding insulating film having low hygroscopicity is a silicon dioxide (SiO2) film containing no fluorine (F). 4. An interlayer insulating film for electrically insulating between a plurality of parallel and overlapping wirings forming a semiconductor device together with a plurality of elements, the interlayer insulating film including silicon (Si), oxygen (O). ) And a fluorine (F) -containing silicon dioxide (SiO ₂ ) film, and the composition of the silicon dioxide film has a structure containing silicon atoms covalently bonded via oxygen (O) atoms, The structure has a composition in which one fluorine (F) atom is bonded to one silicon (Si) atom, and a composition in which two fluorine (F) atoms are bonded to one silicon (Si) atom, and 1 A method of manufacturing a semiconductor device including a composition in which three fluorine (F) atoms are bonded to one silicon (Si) atom, wherein a semiconductor substrate on which elements are formed is maintained in a certain sealed state. First installed in a holding container and heated to a predetermined temperature
And the step of introducing a raw material gas containing at least silicon (Si), oxygen (O), and fluorine (F) into the container in which the heated semiconductor substrate is installed at a predetermined flow rate, and A second step of maintaining a predetermined pressure in the container, and a predetermined voltage is applied to the electrode facing the semiconductor substrate to perform plasma discharge, and silicon dioxide (SiO 2) containing a predetermined equivalent amount of fluorine (F). ₂ ) A third step of depositing a film, and forming a metal wiring film on the silicon dioxide film and patterning it to form a metal wiring of a predetermined row, a predetermined length and a predetermined thickness in a first layer and a predetermined column. A semiconductor device comprising: a fourth step; and a fifth to an mth step of forming metal wirings of the second to nth layers by repeating the above first to fourth steps. The method of production. 5. A source gas containing at least oxygen (O) and containing no fluorine (F) is formed after the step of forming each layer of the interlayer insulating film containing fluorine (F) formed in multiple layers. The method of manufacturing a semiconductor device according to claim 4, wherein a step of introducing at a predetermined flow rate to form a silicon dioxide (SiO ₂ ) film containing no fluorine (F) is provided for each layer. . 6. The source gas is a compound gas containing fluorine (F) as a constituent element, an organic silane gas and an oxidizing gas; a compound gas containing fluorine (F) as a constituent element, an inorganic silane gas and an oxidizing gas; 5. An organic silane gas containing F) as a constituent element and an oxidant gas; and an organic silane gas containing fluorine (F) and oxygen (O) as a constituent element; A method for manufacturing a semiconductor device as described above.