JPH10289902A - Film forming equipment - Google Patents

Abstract

(57) Abstract: Provided is a film forming apparatus capable of forming an interlayer insulating film having a low relative dielectric constant by using a vapor deposition polymerization method in a simple process. A film forming apparatus is a multi-chamber type single-wafer apparatus, and has an L / UL chamber around a core chamber for loading and unloading a Si wafer and the like, and a vapor deposition polymerization. A first processing chamber 4, a second processing chamber 5 for performing heat treatment and ultraviolet irradiation, and a third processing chamber 6 for performing sputtering of aluminum or the like. The substrate 8 is freely transferred from the L / UL chamber 3 to the first to third processing chambers 4 to 6 via the core chamber 2. Above the first processing chamber 4, evaporation sources 40A and 40B for two kinds of raw material monomers A and B are provided with introduction pipes 41A and 41B.
, So that the raw material monomers A and B can be supplied to the substrate 8 from above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for forming a low dielectric constant insulating film used as an interlayer insulating film of a semiconductor device, for example.

[0002]

2. Description of the Related Art Conventionally, as an interlayer insulating film of a semiconductor device, an SOG (Spin on Glass) film or a CV
An SiO ₂ film formed by a D method (Chemical Vapor Deposition) is mainly used. The relative dielectric constant of the interlayer insulating film formed by these methods is about 4,
Recently, with the progress of high integration of LSIs, it has been considered that the reduction of the relative dielectric constant of the interlayer insulating film is a major issue, and an interlayer insulating film having a relative dielectric constant of 4 or less has been required.

[0003] In response to such demands, in recent years, a SiOF film obtained by adding fluorine to an SiO ₂ film formed by a plasma CVD method or a fluorine amorphous carbon film formed by using a gas such as C ₄ F ₈ (plasma polymerization). According to these films, the relative dielectric constant of the interlayer insulating film can be suppressed to about 3.7 to 3.2 in the former and about 2.8 to 2.2 in the latter.

Further, the present inventors have found that various polymer films produced by vapor deposition polymerization can realize a dielectric constant of 2.5 or less.

[0005]

However, such a conventional technique has the following problems. That is, while the SiOF film formed by the above-mentioned plasma CVD method can achieve a low relative dielectric constant, the film characteristics greatly differ depending on the film forming method and the film forming conditions, and the desorption and the hygroscopicity of fluorine in the film are large. It has been pointed out that the dielectric constant deteriorates due to the instability of the film, and it is difficult to apply it as a low dielectric constant material in the future.

On the other hand, in the conventional vapor deposition polymerization method, monomer vapor is always supplied from below the substrate in an apparatus in which the evaporation source is located below the substrate due to its structural easiness. As a result, a film is formed.

However, in a semiconductor device manufacturing process, film formation is performed by a general deposition method. Therefore, in order to use a film formed by vapor deposition polymerization as an interlayer insulating film of a semiconductor device, a substrate must be manufactured. There is a problem that the manufacturing process has to be turned upside down, which complicates the manufacturing process.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and a film forming apparatus capable of forming an interlayer insulating film having a low dielectric constant by a simple process using a vapor deposition polymerization method. The purpose is to provide.

[0009]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, even when the vapor of the raw material monomer was supplied from above the substrate, the vapor deposition polymerization was carried out to achieve a low ratio. They have found that a dielectric polymer film can be formed, and have completed the present invention.

[0010] The present invention has been made based on such knowledge, and the invention according to claim 1 is a film forming apparatus having a plurality of processing chambers for performing a film forming process on a substrate. At least one of the processing chambers is a processing chamber for vapor deposition polymerization, and the processing chamber for vapor deposition polymerization is configured to supply a raw material monomer to the substrate from above. It is a film forming apparatus.

According to the first aspect of the present invention, since the raw material monomer is supplied to the base from above, the base is turned upside down when an interlayer insulating film is formed in a semiconductor device manufacturing process. No need.

In this case, as in the invention described in claim 2,
It is also effective when the evaporation source for supplying the raw material monomer is provided outside the processing chamber for vapor deposition polymerization.

According to the second aspect of the present invention, the vacuum chamber can be made small, and a part of the monomer does not adhere around the evaporation source, so that the cleaning operation becomes easy. Further, it is not necessary to consider the influence of heat on the substrate due to the heating of the monomer.

Various monomers can be used as raw material monomers for vapor deposition polymerization. As diamine monomers for forming polyurea, 4,4'-diaminodiphenylmethane (MDA) and 4,4'-diaminodiphenyl ether are used.
(ODA), 4,4'-bis (4-aminophenoxy) biphenyl, 1,4-bis (4-aminophenoxy) benzene, 2,2'-bis [4- (4-aminophenoxy) phenyl] hexafluoro Propane, 2,2'-bis [4- (4-aminophenoxy) phenyl] propane, 3,3'-dimethyl-4,4'-diaminobiphenyl (O
Aromatic monomers of either TD) or 3,3'-dimethoxy-4,4'-diaminobiphenyl can be used.

As diisocyanate monomers for forming polyurea, 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-bis (4-isocyanatophenoxy) biphenyl, 1,4- Bis (4-isocyanatophenoxy) benzene, 2,2'-bis [4- (4-isocyanatophenoxy) phenyl] hexafluoropropane, 2,2'-bis [4- (4-isocyanatophenoxy) phenyl] Any aromatics of propane, 3,3'-dimethoxy-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI), and paraphenylene diisocyanate Monomers can be used.

Further, as in the third aspect of the present invention, there is provided a heating means capable of controlling the temperature of the base in a range wider than the temperature at the time of manufacturing the semiconductor device and adjusting the heating rate during heating. It is also effective when the processing chamber is provided.

According to the third aspect of the present invention, a substrate on which polyurea is formed by, for example, vapor deposition polymerization is disposed in a processing chamber provided with a heating means, and for example, polyurea does not dissociate with this polyurea. Heat treatment can be performed at a temperature equal to or lower than the upper limit temperature. As a result, the diisocyanate terminal groups in the polyurea react with each other to generate polycarbodiimide, and a polymer film (polycarbodiimide film) having a low dielectric constant can be formed.

In this case, the heating rate is reduced (for example, 2
(° C./min or less) and heating, the depolymerization of the polyurea can be progressed gradually and the diisocyanate terminal groups can be reliably reacted with each other.

According to the third aspect of the present invention, when fabricating a semiconductor device, the polymer film can be heated to a temperature equal to or higher than the maximum temperature of the semiconductor device manufacturing process. Decomposition of the polymer component can be prevented.

In this case, for example, the substrate may be heated so that the temperature of the substrate can be controlled in the range of 20 ° C. to 500 ° C.

The atmosphere in the processing chamber may be air, an inert gas, or a vacuum. In order to suppress the evaporation of monomers in the heat treatment step, the atmosphere in the inert gas is most effective.

In this case, for example, a hot plate can be used as the heating means. If a hot plate is used, a substrate such as a Si wafer can be uniformly heated.

The present invention is also effective when an ultraviolet treatment chamber capable of irradiating the substrate with ultraviolet rays through a window transparent to ultraviolet rays is provided.

According to the fifth aspect of the present invention, in order to improve the heat resistance of the polymer film formed on the substrate, ultraviolet light can be irradiated from outside the processing chamber. The effect of heat (infrared rays) of a lamp or the like can be reduced. In addition, since decomposition products do not adhere to the lamp and the like, and the lamp does not need to be held in a vacuum, there is no need to adopt a special structure that can withstand a pressure difference.

In this case, ultraviolet light having a wavelength of 350 nm or less is applied to the polyurea film before the heat treatment step by 10 mW / cm.
Irradiation of ² or more, and ultraviolet light of a wavelength of 350 nm or less is applied to the film on which polycarbodiimide is generated for 10 m
Irradiation of W / cm ² or more is also effective.

That is, by irradiating a certain amount or more of ultraviolet rays having a specific wavelength, a crosslinked structure is obtained, and the heat resistance of the polymer film is improved.

In this case, the preferable range of the wavelength of the ultraviolet light for improving the heat resistance is 350 to 190 nm, and the more preferable irradiation amount of the ultraviolet light is 100 m
W is a / cm ² ~1W / cm ^2.

In this case, as in the sixth aspect of the present invention,
It is also effective to dispose the heating means in the ultraviolet processing chamber.

According to the sixth aspect of the present invention, the polymer film formed on the substrate can be subjected to ultraviolet irradiation and heat treatment in the same processing chamber, thereby simplifying the structure and steps of the apparatus. become.

Further, a chamber for taking the substrate in and out of the core chamber and a plurality of processing chambers are provided around the core chamber, and the plurality of substrates are connected to each other via the core chamber. There is also an effect when the apparatus is configured to be conveyed to a space.

According to the seventh aspect of the invention, in the process of manufacturing a semiconductor device, an interlayer insulating film can be continuously formed on a plurality of substrates, and the production efficiency of the semiconductor device can be improved. .

[0032]

Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1A shows a schematic configuration of an example of a film forming apparatus according to the present invention. As shown in FIG. 1A, the film forming apparatus 1 is a multi-chamber type single-wafer apparatus, and a Si chamber is provided around a core chamber 2 in which a transfer robot (not shown) is installed.
An L / UL chamber 3 for loading and unloading wafers and the like, a first processing chamber 4 for performing vapor deposition polymerization, a second processing chamber 5 for performing heat treatment and irradiation of ultraviolet rays, A third processing chamber 6 for performing sputtering is disposed, and these are all connected via a gate valve (not shown). In addition, these core chambers 2, L / UL
The chamber 3 and the first to third processing chambers 4 to 6 are connected to a vacuum exhaust system such as a vacuum pump (not shown). Here, the substrate 8 can be freely transferred from the L / UL chamber 3 to the first to third processing chambers 4 to 6 by a robot arranged in the core chamber 2.

FIG. 1B shows a schematic configuration of the first processing chamber 4. As shown in FIG. 1B, above the first processing chamber 4, evaporation sources 40A and 40B of two kinds of raw material monomers A and B are connected via introduction pipes 41A and 41B. Housing 42 of each evaporation source 40A, 40B
A and 42B are provided with evaporation containers 43A and 43B, respectively. Then, raw material monomers A and B for forming polyurea are injected into the evaporation containers 43A and 43B, respectively.

In this case, as the raw material monomers A and B,
For example, 3,3'-dimethyl-4,4'-diaminobiphenyl (O
TD) and 3,3'-dimethyl-4,4'-diisocyanatobiphenyl (TODI).

Further, heaters 44A and 44B for heating the raw material monomers A and B are provided near the evaporation containers 43A and 43B.

On the other hand, a heater H is wound around each of the introduction pipes 41A and 41B so that the temperatures of the raw material monomers A and B can be controlled. In the middle of each of the introduction pipes 41A and 41B, valves 45A and 45 for adjusting the supply amount of each of the raw material monomers A and B are provided.
B are provided, and by opening and closing them, the film thickness can be controlled at the time of forming the vapor-deposited polymer film.

As shown in FIG. 1B, the substrate 8 is
Is supported on a lower susceptor 46 in the processing chamber 4. In addition, a mixing tank 47 formed so as to expand downward is provided at an upper portion of the first processing chamber 4. A heater 48 for heating the vapor of the raw material monomers A and B is provided on the inner wall of the mixing tank 47.

FIG. 2A shows a schematic configuration of the second processing chamber 5. As shown in FIG. 2A, a susceptor 51 having a hot plate 50 for heating the substrate 8 is provided in the second processing chamber 5. The hot plate 50 can control the temperature of the substrate 8 in a wider range (20 to 500 ° C.) than the temperature at the time of manufacturing the semiconductor device.
Moreover, it is configured such that the rate of temperature rise during heating can be adjusted. Further, a window member 52 made of a transparent material such as quartz is provided in an airtight manner above the second processing chamber 5. Further, a high-pressure mercury lamp 53 for irradiating the substrate 8 with ultraviolet rays through the window member 52 is provided above the window member 52.

FIG. 2B shows a schematic configuration of the third processing chamber 6. As shown in FIG. 2B, a DC bipolar sputtering device is provided in the third processing chamber 6. That is, the DC power supply 6 is provided above the third processing chamber 6.
An electrode 61 connected to the electrode 61 is provided, and the electrode 62 holds, for example, an aluminum target 62. The substrate 8 to be processed is supported by the susceptor 63 at the lower part of the third processing chamber 6. In addition, an inert gas such as an argon (Ar) gas is introduced into the third processing chamber 6 through an introduction pipe 64.

FIG. 3 is a process chart showing an example of a method of forming a low dielectric constant insulating film using the present invention. To form an insulating film in the present embodiment, first, in the film forming apparatus 1, the substrate 8 is moved from the L / UL chamber 3 to the first processing chamber 4.
The raw material monomers A and B are introduced into the first processing chamber 4 by opening the valves 45A and 45B, and a polyurea film is formed on the substrate 8 by vapor deposition polymerization (step 1).

In this case, first, each of the valves 45A, 45B
Is closed, the pressure in the first processing chamber 4 is increased to 3 × 10 ⁻³ P
A high vacuum of about a is set, and the raw material monomers A and B are heated to a predetermined temperature by the heaters 44A and 44B. In addition, the introduction pipes 41A and 41B are
Heat to about 0 ° C.

After each raw material monomer A, B reaches a predetermined temperature and a required amount of evaporation is obtained, each valve 45
A and 45B are opened, and the raw material monomers A and B are deposited and deposited on the substrate 8 from above at a predetermined evaporation rate, and after forming a polyurea film, the valves 45A and 45B are closed. In this case, the evaporation rates of the raw material monomers A and B are controlled so as to have a stoichiometric ratio of 1: 1. The temperature in the mixing tank 47 is controlled to be about 105 ° C., and the temperature of the substrate 8 is controlled to be about 92 ° C.

Thereafter, the substrate 8 is transported to the second processing chamber 5, and the polyurea film formed on the substrate 8 is irradiated with ultraviolet rays (step 2). In this case, the ultraviolet irradiation is performed at a wavelength of 3
The irradiation is performed by irradiating ultraviolet rays having a wavelength of 50 nm or less to 10 mW / cm ² or more.

Further, in the second processing chamber 5, the substrate 8
The above polyurea film is subjected to the following heat treatment using the hot plate 50 of the susceptor 51 (step 3).
That is, 250 ° C. to 350 ° C. at a heating rate of 5 ° C./min.
Heat to about the extent, and hold the state for 30 minutes to perform heat treatment (Step 3A).

Further, at a heating rate of about 1 ° C./min, 40
By heating to about 0 ° C., the polyurea is depolymerized, the diamine component is dissociated, and the diisocyanate terminal groups react to form polycarbodiimide (step 3).
B).

The processing atmosphere is, for example, a nitrogen atmosphere of about 1.2 atm in order to evaporate the diamine monomer.

Through such steps, a polymer film (polycarbodiimide film) 10 having a thickness of about 500 nm is formed on the SiO ₂ film 9 of the substrate 8 (Step 4).

If necessary, the substrate 8 can be transferred to the third processing chamber 6 and an aluminum electrode can be formed on the substrate 8 by sputtering.

As described above, according to the present embodiment,
A polymer film containing polycarbodiimide having a very small relative dielectric constant can be easily formed. Further, according to the present embodiment, film formation can be efficiently performed on a large number of substrates 8.

FIGS. 4A to 4F show an example of a process for forming an interlayer insulating film of a semiconductor device by using the present invention. First, as shown in FIG. 4A, for example, silicon (S
i), a silicon thermal oxide film 22 formed on the surface of the semiconductor substrate 21 and having a window formed at a predetermined position, and a first layer formed thereon and patterned. A substrate 31 having the wiring 23 is prepared.

On the surface of the substrate 31, a polyurea film 24a is formed on the entire surface to a desired thickness by vapor deposition polymerization using the film forming apparatus 1 described above, and the polyurea film 24a has a wavelength of 350 nm or less. UV light 10 mW / cm ²
The above irradiation is performed (FIG. 4B).

Then, a heat treatment is performed under the above conditions to generate polycarbodiimide, and an interlayer insulating film 24 made of polycarbodiimide is formed (FIG. 4C).

Next, on the surface of the interlayer insulating film 24, a resist film 25 having been subjected to a predetermined patterning by a resist process is formed (FIG. 4D), and the resist film 25 is dry-etched. The interlayer insulating film 24 exposed at the window opening is removed (FIG. 4E). Then, after removing the resist film 25, a wiring thin film is formed on the entire surface and patterned to form a second-layer wiring 26.

As a result, the first-layer wiring 23 and the second-layer wiring 26 are electrically connected to each other at the window opening portion 27 from which the interlayer insulating film 24 has been removed, and as a result, a multilayer wiring is provided. The semiconductor device 35 can be obtained (FIG. 4F).

According to the present embodiment, since the interlayer insulating film 24 is made of a film containing polycarbodiimide having a low dielectric constant, the first-layer wiring 23 and the second-layer wiring 26 The capacitance of the capacitor formed between them becomes extremely small, and the operating speed of the semiconductor device 35 can be greatly improved.

Further, according to the present embodiment, since the starting monomers A and B are supplied to the substrate 8 from above, the formation of the interlayer insulating film in the manufacturing process of the semiconductor device is performed. It is not necessary to turn the substrate 8 over, and the process can be simplified.

It should be noted that the present invention is not limited to the above-described embodiment, and various changes can be made. For example,
In the above-described embodiment, the polycarbodiimide film is formed by heating the polyurea film formed by vapor deposition polymerization.However, the present invention is not limited to this.For example, a polyimide film and a polyurea film are formed by vapor deposition polymerization. And the like can be applied.

On the other hand, in the above-described embodiment, the ultraviolet light is irradiated before performing the heat treatment on the polyurea film. However, the present invention is not limited to this, and the polycarbodiimide is generated by the heat treatment. Ultraviolet irradiation may be performed later.

Further, in the case of the present invention, such irradiation with ultraviolet rays is not always required. However, if the specific ultraviolet rays are irradiated as described above, the heat resistance of the polycarbodiimide film can be improved. You can do it.

In addition, the present invention can be applied not only to an interlayer insulating film of a semiconductor device but also to various insulating films.

[0061]

EXAMPLES Hereinafter, specific examples of the present invention will be described together with comparative examples. A polycarbodiimide film was formed on a Si wafer using the film forming apparatus 1 shown in FIG.

First, a 6-inch Si wafer (substrate) 8 having a conductivity of 0.02 Ωcm is transferred into the first processing chamber 4, and the substrate 8 on which the SiO ₂ film 9 is formed is vapor-deposited and polymerized. Thus, a polyurea film was formed.

The raw material monomers A and B for forming the polyurea film include 3,3'-dimethyl-4,4'-diaminobiphenyl (OTD) and 3,3'-dimethyl-4,4'- Using diisocyanato biphenyl (TODI) in a high vacuum (3
× 10 ⁻³ Pa), the OTD is 100.0 + 0.1 ° C.,
TODI was simultaneously evaporated at a temperature of 92 + 0.1 ° C. to control the supply amounts of the raw material monomers A and B.

In this case, the composition ratio of OTD and TODI is
The stoichiometric ratio was controlled to be 1: 1. The temperature in the mixing tank 47 was controlled to be about 100 ° C., and the temperature of the substrate 8 was controlled to be 30 ° C.

After forming the polyurea film in this way,
The substrate 8 was transferred to the fourth processing chamber 7 and irradiated with ultraviolet rays having a wavelength of 350 nm or less at 100 mW / cm ^2, and then a predetermined heat treatment was performed on the polyurea film.

In this case, the heat treatment is performed at a temperature increasing rate of 5 ° C./m
The heating was performed by heating to 350 ° C. in, keeping the state for 30 minutes, and then heating to 400 ° C. at a rate of 1 ° C./min. The thickness of the film at this point is 500 n
m.

After performing such a heat treatment, the substrate 8 was transferred to the third processing chamber 6, and an aluminum electrode was formed to a thickness of 200 nm by sputtering to prepare an element for measuring a relative dielectric constant. The relative dielectric constant of this device was measured and found to be 1.50. In this case, the value of the relative dielectric constant is determined by a multi-chip manufactured by Yokogawa Hewlett-Packard Company.
The capacitance was measured using a frequency LCR meter (model 4275A) and determined by calculation. The bias was set to -20V.

On the other hand, as a comparative example, after forming only a polyurea film by vapor deposition polymerization under the same conditions as in the example, an upper electrode was formed to prepare a device for measuring a relative dielectric constant. The relative permittivity of the polyurea film of this device was measured by the same method as in the example, and was 3.8.

[0069]

As described above, according to the present embodiment, a polymer film having a very small relative dielectric constant, particularly a polymer film containing polycarbodiimide can be easily formed. The film can be efficiently formed on the substrate. Further, according to the present invention, since the raw material monomer is supplied to the substrate from above, it is not necessary to turn the substrate over when forming an interlayer insulating film in a semiconductor device manufacturing process. Can be simplified. As described above, when an interlayer insulating film is formed using the present invention, a semiconductor device having a high operation speed can be manufactured efficiently.

[Brief description of the drawings]

FIG. 1A is a schematic configuration diagram of an example of a film forming apparatus according to the present invention. FIG. 1B is a schematic configuration diagram of a first processing chamber.

FIG. 2A is a schematic configuration diagram of a second processing chamber. FIG. 2B is a schematic configuration diagram of a third processing chamber.

FIG. 3 is a process chart showing an example of a method for forming a low dielectric constant insulating film using the present invention.

FIGS. 4A to 4F are process diagrams showing an example of a process of forming an interlayer insulating film of a semiconductor device using the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus 2 ... Core room 3 ... L / UL room 4 ... 1st processing room 5 ... 2nd processing room 6 ... 3rd processing room 8 ...
Substrate 21 Semiconductor substrate 22 Silicon thermal oxide film 23 First layer wiring 24 Interlayer insulating film 24a Polyurea film 25 Resist film
26: Second-layer wiring 31: Substrate 35:
... Semiconductor devices A, B .... Raw material monomers 40A, 40
B ... Evaporation source 41A, 41B ... Introduction tube 45
A, 45B Valve 47 Mixing tank 48
Heater 52: Window member 53: High-pressure mercury lamp H: Heater

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yoshikazu Takahashi 5-9-7 Tokodai, Tsukuba, Ibaraki Pref.

Claims (7)

[Claims] 1. A film forming apparatus having a plurality of processing chambers for performing a film forming process on a substrate, wherein at least one of the plurality of processing chambers is a processing chamber for vapor deposition polymerization. A film forming apparatus, wherein a processing chamber for vapor deposition polymerization is configured to supply a raw material monomer to the substrate from above. 2. The film forming apparatus according to claim 1, wherein an evaporation source for supplying a raw material monomer is provided outside a processing chamber for vapor deposition polymerization. 3. A processing chamber provided with a heating means capable of controlling a temperature of a base within a range wider than a temperature at the time of manufacturing a semiconductor device and adjusting a heating rate at the time of heating. The film forming apparatus according to claim 1, wherein: 4. The film forming apparatus according to claim 3, wherein the temperature of the substrate can be controlled in a range from 20 ° C. to 500 ° C. 5. The film forming apparatus according to claim 1, further comprising an ultraviolet treatment chamber capable of irradiating the substrate with ultraviolet rays through a window transparent to the ultraviolet rays. 6. The film forming apparatus according to claim 5, wherein the heating means is provided in the ultraviolet processing chamber. 7. A plurality of processing chambers and a plurality of processing chambers are provided around the core chamber to transfer the plurality of substrates into and out of the core chamber. The film forming apparatus according to claim 1, wherein: