JP3228251B2 - CVD apparatus and semiconductor device manufacturing method using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CVD apparatus used for forming an interlayer insulating film made of a porous film and a method for manufacturing a semiconductor device using the same, and more particularly, to a CVD apparatus capable of obtaining a stable film quality. And a method for manufacturing a semiconductor device using the same.

[0002]

2. Description of the Related Art In recent years, in the field of manufacturing semiconductor integrated circuits (ICs), along with higher integration of devices, miniaturization of devices in the horizontal direction in accordance with a scaling law has been advanced. Along with this, the wiring width and the wiring interval are also being reduced. However, the parasitic capacitance between wirings increases in inverse proportion to the wiring spacing. This increase in inter-wiring capacitance causes a wiring delay and causes a reduction in the processing speed of the device, and thus has become a major problem in promoting the miniaturization and high integration of the device.

The parasitic capacitance between wirings is proportional to the relative dielectric constant of an insulating film between wirings. Therefore, as one method of reducing the parasitic capacitance, a method of lowering the relative permittivity of the insulating film is effective. An insulating film having a lower relative permittivity than the SiO ₂ film conventionally used as an interlayer insulating film is effective. Forming has been considered. As a typical low dielectric constant interlayer insulating film, there is a SiOF film obtained by adding F to a SiO ₂ film. While the relative dielectric constant of the SiO ₂ film is 3.9 or more, the relative dielectric constant of the SiOF film is as low as 3.4 to 3.7. Other films having a low relative dielectric constant include hydrogen silsesquioxane (HSQ).
A large number of films, inorganic or organic spin-on-glass (SOG) films such as benzocyclobutene (BCB), fluorinated amorphous carbon films, and CVD organic films such as polyparaxylylene films have been reported. The relative permittivity of these films is the lowest at about 2.4.

Further, as a method of further lowering the relative dielectric constant, a method of using a porous film to reduce the film density has been reported. As an example, Xeroge by product name
A coating film called 1 has been reported, and its relative dielectric constant has been reduced to 2.0.

However, the formation of a porous film is described in
As disclosed in U.S. Pat.
Since a desired film is formed by the VD method and then a part of the bond in the film is cut by heat treatment, the cut end of the bond is in an unstable state, and is exposed to the atmosphere. The film quality, such as reacting with H ₂ O therein, is apt to deteriorate. Also,
Since the size of the pores in the porous film is determined by the size of the cut bonds, it is necessary to improve the molecular structure of the raw material itself in order to control the size of the pores, making it difficult to control. ing.

Another method for forming a porous film is disclosed, for example, in Japanese Patent Application Laid-Open No. 9-21797. In the conventional method for forming a porous film described in this publication, a wet gel containing ethanol is applied to the gaps of the network structure on a silicon oxide film, and then ethanol is removed by a supercritical drying method to form a dry gel. Thus, a porous film is formed. Also, a method is described in which a coating film containing a hollow capsule structure covered with a foaming agent is formed on a silicon oxide film, and then the foaming agent is decomposed by heat treatment to form a porous film.

[0007]

However, even with the porous film formed by the method described in the above-mentioned Japanese Patent Application Laid-Open No. 9-21797, the chemical stability of the porous film cannot be said to be sufficient.

The present invention has been made in view of the above problems, and has as its object to provide a CVD apparatus capable of obtaining a porous film having a stable film quality and a method of manufacturing a semiconductor device using the same. .

[0009]

A CVD apparatus according to the present invention is a raw material for a chamber, a susceptor arranged in the chamber for mounting a semiconductor substrate, and an interlayer insulating film to be formed on the semiconductor substrate. Source gas supply means for supplying a source gas into the chamber, and after forming the interlayer insulating film,
Evaporates by heating and separates from the interlayer insulating film
A spray means Kakeru can blow the particles to the surface of the semiconductor substrate during formation of the interlayer insulating film, and having a.

In the present invention, particles are dispersed in the interlayer insulating film by the spraying means during the formation of the interlayer insulating film.
Therefore, voids can be formed by subsequently removing particles in the interlayer insulating film. The porous film formed in this manner has stable film quality, since the bonds in the porous film are not cut off and the pores are not formed. In addition, since the size of the pores can be controlled by adjusting the size of the particles, the control of the size of the pores is easy.

[0011] The method of manufacturing a semiconductor device according to the present invention, the interlayer insulating vaporize the particles by particles on the semiconductor substrate to a heat treatment step and the interlayer insulating film is formed by CVD an interlayer insulating film dispersed A step of forming a plurality of interlayer insulating films having holes on the semiconductor substrate by repeating a step of forming a plurality of holes in the film. Note that voids are formed between the interlayer insulating films.
May have different densities.

Another method of manufacturing a semiconductor device according to the present invention.
Uses CVD to form an interlayer insulating film in which particles are dispersed on a semiconductor substrate.
Forming step and heat treating this interlayer insulating film
By vaporizing the particles, a plurality of particles are formed in the interlayer insulating film.
Forming a hole in the interlayer insulating film.
The forming step is performed while supplying a source gas for the interlayer insulating film.
Does not react with the source gas on the surface of the semiconductor substrate
It is characterized by having a step of spraying particles.

The interlayer insulating film is made of polyparaxylyl
It may be a ren film.

Still another method of manufacturing a semiconductor device according to the present invention.
The method is based on poly-para-xylylene in which particles are dispersed on a semiconductor substrate.
Of forming an interlayer insulating film made of silicon by a CVD method
And heat treating the interlayer insulating film to form the particles.
Forming a plurality of holes in the interlayer insulating film by vaporizing
And the following.

In the method of the present invention, a layer in which particles are dispersed
An inter-insulating film is formed by a CVD method, and the particles are vaporized.
Holes, forming a polar as an interlayer insulating film.
Film quality is stable. In addition, interlayer by CVD method
Since the insulating film is formed, the size of the particles is adjusted to
It is easy to control the size of the holes.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a CV according to an embodiment of the present invention will be described.
The device D will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic diagram showing a CVD apparatus according to an embodiment of the present invention.

In the CVD apparatus according to the embodiment of the present invention, a susceptor 4 is disposed in a chamber 6 in the same manner as a normal apparatus, and a silicon substrate 5 as a material to be processed is placed on the susceptor 4. Is done. The temperature of the susceptor 4 is adjusted to, for example, about −40 ° C. during film formation. Further, a pipe provided with a turbo pump 7 and a dry pump 8 for adjusting the atmospheric pressure in the chamber 6 is connected to the chamber 6.

Further, a bottle 2 containing diparaxylylene ([2,2] paracyclophane) 11, which is a solid raw material for the membrane, is provided outside the chamber 6. The bottle 2 is provided with a heating device (not shown) such as a heater for heating and vaporizing the diparaxylylene 11. Further, a pyrolysis furnace 3 that further heats and decomposes diparaxylylene gas to generate a paraxylylene monomer is connected to the bottle 2. The pyrolysis furnace 3 has a chamber 6
The paraxylylene monomer generated in the pyrolysis furnace 3 is supplied to the chamber 6. In addition,
The bottle 2 and the pipe 9 connected to the bottle 2 are covered with a heater 10. Furthermore, the pipe 1 to which Ar gas is supplied is connected to the chamber 6. In addition, a nozzle is provided at the tip of the pipe 1, and the diameter of the mouth is about 1.
mm.

In the CVD apparatus according to the embodiment of the present invention, the Ar gas is supplied from the pipe 1 to the surface of the silicon substrate 5 at a high speed. At this time, since the volume of the Ar gas expands rapidly due to the pressure difference between the pipe 1 and the chamber 6, the gas temperature decreases due to adiabatic expansion, and the rapidly cooled Ar gas solidifies to form some clusters. Further, a paraxylylene monomer is supplied into the chamber 6 from the pipe 9. Then, a polyparaxylylene film is formed by a polymerization reaction of paraxylylene monomer on the silicon substrate 5 cooled to −40 ° C. At this time, since Ar clusters are supplied at the same time, the Ar clusters are included in the film. A polyxylylene film containing is formed.
Thereafter, by heat-treating the polyparaxylylene film containing the Ar cluster, the Ar cluster is vaporized and removed from the film, whereby a porous film having stable film quality is formed.

Next, the CVD according to the above-described embodiment of the present invention will be described.
A method of manufacturing a semiconductor device according to an embodiment method of the present invention using the device will be described. 2A to 2C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the first embodiment of the present invention in the order of steps.

In the method of the first embodiment, first, FIG.
As shown in FIG. 1A, a plasma CVD method using, for example, SiH ₄ and N ₂ O as a first interlayer insulating film is performed.
An SiO ₂ film 22 having a thickness of 20 nm is formed on a silicon substrate 21. Next, a polyparaxylylene film 23 having a thickness of, for example, 400 nm is formed on the SiO ₂ film 22 by a low pressure (LP) CVD method using the CVD apparatus shown in FIG.

In forming the polyparaxylylene film 23, first, the silicon substrate 21 is placed on the susceptor 4,
The diparaxylylene 11 is heated to 180 ° C. in the bottle 2 and vaporized. Next, the diparaxylylene 11 is further decomposed by further heating it to 650 ° C. in the pyrolysis furnace 3 to produce a paraxylylene monomer. Then A
r gas is supplied from the pipe 1 to the chamber 6 at a flow rate of 100 sccm.
While being introduced into the chamber, the decomposed monomer is introduced into the chamber 6, and is polymerized on the SiO ₂ film 22 formed on the silicon substrate 21 mounted on the susceptor 4 cooled to −40 ° C. A polyparaxylylene film 23 is formed. At this time, the Ar gas is ejected from a nozzle having a mouth diameter of 1 mm or less.
The gas is rapidly cooled by the adiabatic expansion and solidified. Therefore, many Ar clusters 24 are formed in the polyparaxylylene film 23 during the film formation.

After forming the polyparaxylylene film 23 containing the Ar cluster 24, as shown in FIG.
The silicon substrate 21 is taken out of the CVD apparatus, and 300 ° C.
The polyparaxylylene film 23 on which the Ar cluster 24 is formed is annealed in the vacuum atmosphere described above. As a result, the Ar cluster 24 in the polyparaxylylene film 23 is vaporized and desorbed from the polyparaxylylene film 23. As a result, many holes 25 are formed in the polyparaxylylene film 23, and the polyparaxylylene film 23a is formed as a porous film.

Thereafter, as shown in FIG. 2C, plasma CVD using SiH ₄ and N ₂ O as the cap film.
The SiO ₂ film 26 having a thickness of 50 nm is formed on the polyparaxylylene film 23a by the
A layered interlayer insulating film is completed.

According to the method of this embodiment, the polyparaxylylene film 23 containing the Ar cluster 24 is formed by using the above-mentioned CVD apparatus, and is subjected to a heat treatment. Polyparaxylylene film 23
a can be formed.

The temperature of the bottle 2 when forming the polyparaxylylene film 23 is preferably 100 to 300 ° C., and more preferably 150 to 200 ° C. Further, the temperature of the pyrolysis furnace 3 is preferably 500 to 800 ° C, more preferably 600 to 700 ° C.
It is. Further, the temperature of the susceptor 4 is preferably -50 to 50C, more preferably -40 to 0C. Furthermore, the pressure in the chamber 6 is 0.01 to 5
It is preferably 0 Torr, more preferably 0.1 Torr.
1 to 0.5 Torr. Further, the supply amount of Ar is 1
It is preferably from 0 to 500 sccm, and more preferably from 20 to 100 sccm.

Although Ar gas is used as a raw material of clusters formed in the polyparaxylylene film 23,
This raw material is not particularly limited as long as it is in a solid or liquid state at the film forming temperature and can be contained in the interlayer insulating film.

The conditions for annealing the interlayer insulating film containing clusters are as follows: if the annealing temperature is in the range of 200 to 450 ° C. and the atmosphere does not contain O ₂ gas, the pressure, the presence or absence of plasma, and the time Etc. are not particularly limited.

Next, a method of manufacturing a semiconductor device according to a second embodiment of the present invention will be described. 3A to 3C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps.

In the second embodiment, first, FIG.
As shown in FIG. 1A, an SiO ₂ film 32 having a thickness of, for example, 25 nm is formed on a silicon substrate 31 by a CVD method as a first interlayer insulating film. Next, using the CVD apparatus shown in FIG.
A polyparaxylylene film 33 a of nm is formed on the SiO ₂ film 32.

When forming the polyparaxylylene film 33a, the temperature of the furnace of the CVD apparatus is set to, for example, 500.degree. As a result, the progress of thermal decomposition of the vaporized diparaxylylene becomes insufficient. Then, diparaxylylene having insufficient thermal decomposition is supplied into the chamber 6. Therefore, many undecomposed diparaxylylene clusters are formed during the film formation. Thereafter, this is annealed in a vacuum atmosphere at 400 ° C. to desorb undecomposed diparaxylylene,
A large number of holes 34a are formed in the polyparaxylylene film 33a.

In the present embodiment, the supply of Ar gas is not performed.

Thereafter, similarly, film formation and annealing of polyparaxylylene are repeated three times to form a large number of holes 34b.
Polyparaxylylene film 33b containing a number of holes 3
A polyparaxylylene film 33c containing 4c and a polyparaxylylene film 33d containing many holes 34d are sequentially formed. Thus, a polyparaxylylene film as a porous film having a four-layer structure is formed.

Thereafter, as shown in FIG. 3C, plasma CVD using SiH ₄ and N ₂ O as a cap film.
By a method, for example, a SiO ₂ film 35 having a thickness of 50 nm is formed on the polyparaxylylene film 33d.

According to the method of this embodiment, a polyparaxylylene film containing undecomposed dipolyparaxylylene is formed by using the above-mentioned CVD apparatus, and this film is heat-treated. Polyparaxylylene films 33a to 33d can be formed as the formed porous films.

In the method of this embodiment, the temperature of the thermal decomposition furnace was changed to add diparaxylylene to the polyparaxylylene film. In addition, a separate supply system for diparaxylylene was provided to control the supply amount. May be performed. Further, by making the supply amount of the source gas different at the time of forming each polyparaxylylene, it is possible to form four porous polyparaxylylene films having different film densities and relative dielectric constants between the respective films. It is.

Further, by repeating the step of forming an interlayer insulating film using particles as in the method of the first embodiment, a multilayer film can be formed as in the method of the second embodiment. Also in this case, the relative dielectric constant may be adjusted by making the vacancy density between the interlayer insulating films different.

[0038]

As described in detail above, according to the present invention,
Since an interlayer insulating film in which particles are dispersed is formed by a CVD method and the particles are vaporized to form pores, a porous film having stable film quality can be obtained as the interlayer insulating film. By adjusting the size of the particles, the size of the pores can be controlled, so that the control is easy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a CVD apparatus according to an embodiment of the present invention.

FIGS. 2A to 2C are cross-sectional views showing a method of manufacturing a semiconductor device according to the first embodiment of the present invention in the order of steps.

FIGS. 3A to 3C are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention in the order of steps.

[Explanation of symbols]

1, 9; piping 2, bottle 3, pyrolysis furnace 4, susceptor 5, silicon substrate 6, chamber 7, turbo pump 8, dry pump 10, heater 11, diparaxylylene 21, 31, silicon substrate 22, 26, 32; SiO ₂ film 23, 23a, 33a, 33b, 33c, 33d; polyparaxylylene film 24; Ar cluster 25, 34a, 34b, 34c, 34d;

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/316 H01L 21/31

Claims (6)

(57) [Claims] A chamber; a susceptor disposed in the chamber for mounting a semiconductor substrate; and a source gas supply for supplying a source gas for forming an interlayer insulating film to be formed on the semiconductor substrate into the chamber. Means and the interlayer insulating film
Is heated after the film is formed to vaporize and cause the interlayer insulation
CVD apparatus characterized by comprising a spray unit particles released from the membrane Kakeru can blow the surface of the semiconductor substrate during formation of the interlayer insulating film. Form wherein a plurality of holes in the interlayer insulation film to vaporize the particles by particles on the semiconductor substrate to a heat treatment step and the interlayer insulating film is formed by CVD an interlayer insulating film dispersed Forming a plurality of interlayer insulating films having holes on the semiconductor substrate by repeating the steps of: 3. The method of manufacturing a semiconductor device according to claim 2 , wherein the density of holes is different between the respective interlayer insulating films. 4. Interlayer insulation in which particles are dispersed on a semiconductor substrate
A step of forming a film by a CVD method, and
The particles are vaporized by heat treatment, and the interlayer insulation is formed.
Forming a plurality of holes in the film,
The step of forming an insulating film includes the step of:
What is the source gas on the surface of the semiconductor substrate while supplying
It is characterized by having a process of spraying particles that do not react
Semiconductor device manufacturing method. 5. The semiconductor device according to claim 2, wherein the interlayer insulating film is a polyparaxylylene film.
13. The method for manufacturing a semiconductor device according to item 9. 6. A polyparameter in which particles are dispersed on a semiconductor substrate.
Forming an interlayer insulating film of xylylene by CVD
And heat-treating the interlayer insulating film.
Vaporizing the particles to form a plurality of holes in the interlayer insulating film;
Manufacturing a semiconductor device, comprising the steps of:
Method.