JPH08181133A - Dielectric material and manufacture of dielectric film - Google Patents

Abstract

PURPOSE: To contrive to reduce the dielectric constant of a dielectric film, which has a heat resistance, a moisture absorption and a plasma resistance and is used for an insulating film in a semiconductor device, and to make it possible to apply the dielectric film to a process of manufacturing the semiconductor device. CONSTITUTION: A dielectric material 1 is one consisting of a structure, wherein fullerene (C60 or C70 having a chemical space) 3 are dispersed in a dielectric base material (a silicone, an amorphous fluororesin, a polyimide and a poly-para- xylylene or polyamide compound) 2. A dielectric film consisting of the dielectric material 1 is manufactured by a method wherein the fullerene are added to a polysiloxane polymer to manufacture a coating liquid or a polyimide monomer, an amorphous fluororesin monomer or a poly-para-xylylene monomer is dissolved in an organic solvent containing an alcohol as its main component and the fullerene are added to the solution to manufacture a coating liquid, then, the coating liquid is extended on a substrate to form a coat film and the coat film is cured to form the dielectric film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric used for an insulating film of a semiconductor device, and particularly, a dielectric having a low dielectric constant of 3 or less used in a device process of 0.25 μm design rule or less. And a method for manufacturing a dielectric film.

[0002]

2. Description of the Related Art With the demand for miniaturization of semiconductor interlayer insulating films, lower power consumption, and higher speed, lower dielectric constants of interlayer insulating films are required. In order to lower the dielectric constant, (a) in the organic film, the polarizability of the monomer molecule itself forming the polymer is lowered. (B) There is a method of reducing the number of molecules per unit volume to form a so-called rough film. Methods (a) for lowering the polarizability include (a) decreasing the polarizability of the constituent elements, and (b) improving the symmetry of the molecule to reduce the polarizability of the entire molecule. is there.

The currently proposed low dielectric film has a low dielectric constant by containing an element having a small polarizability [carbon (C), fluorine (F), etc.] in the film. As a result, a dielectric constant of about 1.5 to 2.5 has been realized so far.

In a low dielectric material containing carbon atoms, organic S
OG (Spin on glass), polyimide, polyparaxylylene, etc. are known. It is said that these materials have a low dielectric constant by containing a carbon atom as an alkyl group to reduce the density of the material and reduce the polarizability of the molecule itself. Further, these materials not only have a low dielectric constant but also have heat resistance essential as a semiconductor material. The organic SOG has a siloxane structure, the polyimide has an imide bond, and the polyparaxylylene becomes a polymer of a benzene ring, so that each has heat resistance and plasma resistance.

On the other hand, as a low dielectric film containing fluorine atoms, a SiO ₂ film containing fluorine (F) (hereinafter referred to as a SiOF film) is drawing attention. This film reduces the density by terminating the Si-O-Si bond with a fluorine atom,
The polarizability is lowered due to the low polarizability of fluorine itself. This material is excellent in plasma resistance and heat resistance because it does not contain carbon atoms. However, since the dielectric constant is about 2.5 to 3.5, the low dielectric film has a slightly higher dielectric constant. Further, a film has been proposed in which the polarizability of the entire film is lowered by reducing the number of molecules per unit volume without changing the polarizability of the molecule. It has been attempted to realize a low dielectric constant by forming such a rough film.

[0006]

However, a film containing carbon atoms as an alkyl group cannot be used as an interlayer insulating film as it is because it has poor heat resistance, hygroscopicity and plasma resistance. Therefore, it was necessary to develop a material having excellent heat resistance, hygroscopicity, and plasma resistance. Further, in a rough film, there are many gaps in the film, so that moisture easily enters into the gaps, and the bond is weak, so that there is a problem that thermal decomposition easily occurs.

The present invention has a low dielectric constant, heat resistance, hygroscopicity,
An object of the present invention is to provide a method of manufacturing a dielectric and a dielectric film having excellent plasma resistance.

[0008]

The present invention is a method of manufacturing a dielectric and a dielectric film, which has been made to achieve the above object. That is, the dielectric is a fullerene dispersed in a dielectric substrate. This fullerene is composed of, for example, C ₆₀ or C ₇₀ having a chemical space. The dielectric substrate is made of silicone, amorphous fluororesin, polyimide, polyparaxylylene or polyamide compound.

The first method for producing a dielectric film is to add a fullerene to polycyclosiloxane polymer to produce a coating solution,
Then, the coating solution is spread on the substrate to form a coating film, and then the coating film is cured to form a dielectric film. The second method for producing a dielectric film is to dissolve a polyimide monomer, an amorphous fluororesin monomer or a polyparaxylylene monomer in an organic solvent containing alcohol as a main component and add fullerene to form a coating solution. Manufacturing, then spread the coating solution on the substrate to form a coating film,
After that, the coating film is cured to form a dielectric film. In the first and second manufacturing methods, the amount of fullerene added is 10 wt% or more and 30 wt% or less with respect to the coating liquid.

[0010]

In the above-mentioned dielectric, since the fullerene such as C ₆₀ or C ₇₀ having a space in the chemical structure is dispersed in the dielectric base material as the main material, there is a space in the dielectric. Like Therefore, the number of molecules per unit volume is reduced, so that the low dielectric constant is realized. Moreover, in C ₆₀ or C ₇₀ of fullerene, a plurality of carbon 6-membered rings and a plurality of carbon 5 -membered rings are bonded to each other in a substantially spherical shape, so that C ₆₀ has a 32-hedral structure (a 6-membered ring has 20 faces, (Member side is 12 sides), C ₇₀ is 3
It has a heptahedron structure (25 faces in a 6-membered ring and 12 faces in a 5-membered ring), and the inside thereof is a space. Therefore, since H ₂ O cannot enter from the outside of the fullerene to the inside thereof, the hygroscopicity does not decrease due to the addition of the fullerene. Further, in the case where the dielectric base material is formed of a material having a dielectric constant of about 2.5 to 3.0 such as silicone, amorphous fluororesin, polyimide, polyparaxylylene or polyamide compound, By including fullerene, the number of molecules per unit volume is reduced, and the polarizability of the entire film is lowered. As a result, the dielectric constant of the dielectric material containing fullerene is about 1.5 to 2.5. In addition, because the dielectric base material has relatively excellent heat resistance, moisture resistance, plasma resistance, etc., and because the fullerene bond is strong, the heat resistance, moisture resistance, and plasma resistance of the dielectric material even when fullerene is included. Almost no deterioration of sex.

In the first method for producing a dielectric film described above, fullerene is added to polysiloxane metal to produce a coating solution, so that the fullerene is uniformly dispersed in the coating solution. Then, the coating liquid is spread on the substrate to form a coating film, and then the coating film is cured to form a dielectric film, so that the dielectric film is formed in a state in which fullerenes are substantially evenly dispersed. . Therefore, the dielectric constant is almost uniform and low over the entire dielectric film.

In the second method for producing the dielectric film, the polyimide monomer, the amorphous fluororesin monomer or the polyparaxylylene monomer is dissolved in an organic solvent containing alcohol as a main component, and fullerene is added. Since the coating solution is manufactured by the above method, the fullerene is uniformly dispersed in the coating solution. Next, the coating liquid is spread on the substrate to form a coating film, and then the coating film is cured to form a dielectric film, so that the dielectric film is formed in a state in which fullerenes are uniformly dispersed. Therefore, the dielectric constant is uniform over the entire dielectric film, and the dielectric constant of the dielectric film is about 1.5 to 2.5.

In the first and second manufacturing methods, the amount of fullerene added is 10 wt% or more and 30 w with respect to the coating liquid.
Since it is t% or less, the dielectric film has a low dielectric constant without impairing heat resistance, process resistance, and hygroscopicity. However, when the addition amount of fullerene is less than 10% by weight, a space due to fullerene is not sufficiently formed in the dielectric film, so that the low dielectric constant is insufficient. On the other hand, when the added amount of fullerene is more than 30 w%, the heat resistance and plasma resistance of the dielectric film cannot be applied to the manufacturing process of the semiconductor device because the fullerene is contained too much.
Therefore, the addition amount of fullerene is preferably set within the above range.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 1, the dielectric 1 is a dielectric substrate.
Material 2 and fullerenes 3 distributed almost evenly inside
Consists of. As the dielectric base material 2, silicone, non-silicon
Crystalline fluororesin, polyimide, polyparaxylylene,
Is a polyamide compound. Also, fullerene 3 is
A plurality of carbon 6-membered rings and a plurality of carbon 5 membered rings are formed into a substantially spherical shape.
It is combined with C ₆₀Or C₇₀Consists of. did
So, C₆₀Is a 32-sided structure, C₇₀Forms a 37-sided structure
And the inside of them is a space (not shown)
It

In the dielectric 1, the fullerene 3 such as C ₆₀ or C ₇₀ having a space in the chemical structure is dispersed in the dielectric base material 2 which is the main material. There is a space (not shown) for the fullerene 3. Therefore, the number of molecules per unit volume is reduced, so that the low dielectric constant is realized. Moreover, C ₆₀ or C ₇₀ of the fullerene 3 has a plurality of carbon 6-membered rings and a plurality of carbon 5 -membered rings bonded to each other in a substantially spherical shape, so that H ₂ O can enter from the outside of the fullerene 3 to the inside thereof. Absent. Therefore, even if the fullerene 3 is added, the hygroscopicity of the dielectric 1 does not decrease.

If the dielectric base material 2 is formed of silicone, amorphous fluororesin, polyimide, polyparaxylylene or polyamide compound (dielectric constant of about 2.5 to 3.5), The inclusion of the fullerene 3 reduces the number of molecules per unit volume, and the fullerene 3 reduces the dielectric constant, so that the dielectric constant of the dielectric 1 is 1.5.
It will be about 2.5. Furthermore, since the dielectric base material 2 is relatively excellent in heat resistance, humidity resistance, and plasma resistance, and the fullerene 3 is strongly bonded, the heat resistance, humidity resistance, and There is almost no deterioration in plasma resistance.

Next, an example in which the dielectric 1 is applied to an interlayer insulating film of a semiconductor device will be described with reference to the schematic sectional view of the structure of FIG.

As shown in FIG.
2 is formed. On the substrate 11, the wiring 1
The dielectric film 21 made of the dielectric (1) described in FIG. 1 is formed so as to fill and cover the space between the two. Therefore, the fullerenes 3 are substantially evenly dispersed inside the dielectric film 21. Therefore, the dielectric film 21 is a low dielectric film having excellent moisture resistance, heat resistance, and process resistance, and having a dielectric constant of about 1.5 to 2.5.
Since FIG. 2 is drawn schematically, the fullerene 3 is smaller and more included than the illustrated shape.

Next, a first embodiment of a method of manufacturing a dielectric film made of the dielectric 1 described with reference to FIG. 1 will be described below.

First, a silicon compound (general formula RnSi (O
H) _4-n ) and additives [diffusion impurities {eg phosphorus oxide (P ₂ O ₅ ), boron oxide (B ₂ O ₃ ), etc.], glass forming agents (eg silanol), organic binders (eg H ₂ O))] is dissolved in an organic solvent [alcohol (eg ethyl alcohol, methyl alcohol etc.) as a main component, ester (eg isobutyl acetate etc.), ketone (eg acetophenone etc.)] is used. Then, fullerene (C ₆₀ or C ₇₀ ) was added to and dispersed in this polysiloxane polymer to prepare a coating liquid. Fullerene is 10w% to 30w with respect to the coating liquid
% Was added within the range.

Next, as a coating method, for example, a spin coating method was used to coat the coating liquid on the substrate. For example, the coating liquid is supplied onto a substrate that rotates at a low speed (for example, a constant rotation speed within a range of 10 rpm to 100 rpm), and then the substrate is rotated at a predetermined rotation speed (for example, a rotation speed within a range of 1000 rpm to 5000 rpm). The coating liquid supplied onto the substrate was extended by rotating the substrate to form a coating film on the surface of the substrate.

After that, the coating film formed on the substrate was cured to form a dielectric film. The coating film can be cured by, for example, 8
It was dried by baking at 0 ° C. for 1 minute and 150 ° C. for 2 minutes, and further baked at a predetermined temperature in the temperature range of 300 ° C. to 500 ° C. As a result, it was possible to form a dielectric film having a low dielectric constant with a constant film thickness in the range of 100 nm to 500 nm. The dielectric constant of this dielectric film was 2.5 to 3.5. . The heat resistance is 4
00 ° C, plasma etching resistance is the same as conventional SOG (Spin
Similar to the on glass) film, the hygroscopicity was at a level where it could be left in the air. Therefore, it was found that this dielectric film can be used in the semiconductor device process.

In the manufacturing method of the first embodiment, the fullerene is added to the polysiloxane polymer to prepare the coating liquid, so that the fullerene is substantially evenly dispersed in the coating liquid. Then, the coating liquid was spread on the substrate to form a coating film, and the coating film was cured to form a dielectric film, so that the fullerene is uniformly dispersed in the dielectric film. Therefore, the dielectric constant is uniform and low over the entire dielectric film.

Since the amount of fullerene added is 10 wt% or more and 30 wt% or less with respect to the coating liquid, the dielectric film has a low dielectric constant without impairing heat resistance, process resistance and hygroscopicity. However, the amount of fullerene added is 10w%
If it is less than the above range, the space due to the fullerene in the dielectric film does not reach a sufficient amount, so that the lowering of the dielectric constant becomes insufficient. On the other hand, when the added amount of fullerene is more than 30 w%, the heat resistance and plasma resistance of the dielectric film cannot be applied to the manufacturing process of the semiconductor device because the fullerene is contained too much. Therefore, the addition amount of fullerene is preferably set within the above range.

Next, a second embodiment of the method of manufacturing the dielectric film described with reference to FIG. 2 will be described below. The second embodiment is different only in the components of the coating liquid described in the first embodiment.

That is, the poly described in the first embodiment is used.
Low polyparaxylylene instead of siloxane polymer
Was used. In addition to this polyparaxylylene, it has a low dielectric constant.
It is also possible to use the polyimide or amorphous fluororesin
Noh. First, organic polyparaxylylene monomer
Solvent [alcohol (eg ethyl alcohol, isopropyl alcohol
The main component is pill alcohol, etc.
Sobutyl etc.), ketones (eg acetophenone etc.)]
Dissolve and add fullerene (C₆₀Or C ₇₀)
Then, a coating liquid was manufactured. Fullerene is for coating liquid
It was added within the range of 10 w% or more and 30 w% or less. Low dielectric
When using polyimide or amorphous fluorocarbon resin
In the same manner as above, a low dielectric constant polyimide monomer
Or dissolve amorphous fluororesin monomer in organic solvent
Then, add fullerene to the solution to make a coating solution.
I just need.

Then, the coating solution was applied onto the substrate by the same spin coating method as described in the first embodiment to form a coating film. After that, the coating film was cured by heat curing treatment to form a dielectric film having a constant film thickness in the range of 100 nm to 500 nm. The dielectric constant of this dielectric film was 1.5 to 2.5. . Further, the above-mentioned dielectric film had heat resistance, plasma etching resistance and moisture absorption at a level applicable to a semiconductor process. Therefore, this dielectric film can be used in a semiconductor device process.

In the second method for producing the dielectric film, fullerene is added to a solution prepared by dissolving a polyimide monomer, an amorphous fluororesin monomer or a polyparaxylylene monomer in an organic solvent containing alcohol as a main component. Since the coating liquid was manufactured by the above method, the fullerene is substantially evenly dispersed in the coating liquid. Then, the coating liquid is spread on the substrate to form a coating film, and then the coating film is cured to form a dielectric film, so that the dielectric film is formed in a state in which fullerenes are substantially evenly dispersed. . for that reason,
The dielectric film exhibits a substantially uniform dielectric constant over the entire surface thereof, and the dielectric constant of the dielectric film is about 1.5 to 2.5. Regarding the amount of fullerene added, for the same reason as described in the first embodiment, 10 w% or more and 3
It is preferably set in the range of 0 w% or less.

Next, an example in which the dielectric film described in the first and second embodiments is applied to an interlayer insulating film of a semiconductor device is shown in FIG.
Will be described with reference to manufacturing process diagrams.

As shown in FIG. 3A, an insulating film 41 is formed on the surface of the substrate (eg, silicon substrate) 11. This insulating film 41 is made of, for example, silicon oxide. On such an insulating film 41 of the substrate 11, a metal film for metal wiring is formed by a film forming technique typified by, for example, a sputtering method, a vapor deposition method, a CVD method or the like. Then, the metal film is patterned by the lithography technique and etching to form the metal wiring 42.

After that, the coating film 31 is formed by the method described in the first embodiment or the second embodiment so as to fill the space between the metal wirings 42 and cover the metal wirings 42. Here, as an example, as described in the second embodiment, a monomer of polyparaxylylene was dissolved in an organic solvent, and fullerene 3 was added to the solution 32 to prepare a coating liquid. Fullerene 3 is 10 for coating liquid
It was added within the range of w% to 30 w%. Then, the coating liquid was applied onto the insulating film 41 by the spin coating method to form the coating film 31. As a matter of course, it is possible to use a coating liquid in which fullerene is added to the polysiloxane polymer described in the first embodiment, and besides the monomer of polyparaxylylene, the monomer of polyimide or the monomer of amorphous fluororesin. Can also be used.

After that, as shown in FIG. 3B, the coating film 31 is thermally cured to form the dielectric film 21. The heat curing at this time was performed at 80 ° C. in the same manner as in the first embodiment.
Minutes and baking for 2 minutes at 150 ℃, 300 ℃ ~ 500
The baking was performed at a predetermined temperature in the temperature range of ° C.

Then, as shown in (3) of FIG.
Silicon oxide (Si
An O ₂ ) film 43 is formed. In this way, the dielectric film 21 having a low dielectric constant (dielectric constant of about 1.5 to 2.5)
And the silicon oxide film 43 are completed to complete the interlayer insulating film 44.

[0035]

As described above, according to the dielectric material of the present invention, fullerene is dispersed in the dielectric base material.
A low dielectric constant can be realized by reducing the number of molecules per unit volume due to the space of fullerene. Moreover, the dielectric material of the present invention is excellent in moisture resistance, heat resistance, and plasma resistance even if it contains fullerenes, and thus can be applied to a semiconductor manufacturing process. When the dielectric base material is a dielectric material of silicone, amorphous fluororesin, polyimide, polyparaxylylene, or a polyamide compound, a dielectric constant of about 1.5 to 2.5 can be obtained by including fullerene. it can.

In the production method of the present invention, a fullerene is added to polycyclosiloxane polymer to produce a coating solution, or an organic solvent containing alcohol as a main component is used in a polyimide monomer, an amorphous fluororesin monomer or a polyparapolymer. Since the coating solution is prepared by dissolving the xylylene monomer and adding the fullerene, the fullerene can be dispersed almost uniformly in the coating solution. Then, the coating liquid is spread on the substrate to form a coating film and cured to form a dielectric film, so that the dielectric film can be formed in a state in which fullerenes are evenly dispersed. Therefore, a dielectric film having a uniform dielectric constant can be formed over the entire dielectric film.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a main part of a dielectric of the present invention.

FIG. 2 is a schematic cross-sectional view of a structure in which a dielectric is applied to an interlayer insulating film.

FIG. 3 is a manufacturing process diagram of an interlayer insulating film using the manufacturing method of the present invention.

[Explanation of symbols]

 1 Dielectric 2 Dielectric Substrate 3 Fullerene 21 Dielectric Film 31 Coating Film

Claims (5)

[Claims] 1. A dielectric material comprising a dielectric base material and fullerenes dispersed in the dielectric base material. 2. The dielectric according to claim 1, wherein the dielectric base material is made of silicone, amorphous fluororesin, polyimide, polyparaxylylene, or a polyamide compound. 3. A coating solution is prepared by adding fullerene to polycyclosiloxane polymer, and then the coating solution is spread on a substrate to form a coating film, and then the coating film is cured to form a dielectric film. A method of manufacturing a dielectric film, comprising: 4. A coating liquid is produced by dissolving a polyimide monomer, an amorphous fluororesin monomer or a polyparaxylylene monomer in an organic solvent containing alcohol as a main component and adding fullerene to the coating liquid, and then applying the coating liquid. A method for producing a dielectric film, comprising: spreading a liquid on a substrate to form a coating film; and then curing the coating film to form a dielectric film. 5. The method for producing a dielectric film according to claim 3 or 4, wherein the addition amount of the fullerene is 10 wt% with respect to the coating liquid.
% Or more and 30 wt% or less, a method for manufacturing a dielectric film.