JP2000021866A - Semiconductor manufacturing apparatus and method of forming polyimide film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide with a simple process a semiconductor manufacturing apparatus for forming a low specific dielectric const. polymer composite film for an layer insulation film, having stable physical properties, and a method of easily forming the low specific dielectric const. polyimide film in a semiconductor element through evaporation-polymerization. SOLUTION: In this semiconductor manufacturing apparatus, gas flow rate controllers 11A, 11B are provided between an evaporation-polymerizing chamber 3, and monomer evaporation sources for controlling the feed rates of raw material monomers A, B are provided for the evaporation-polymerization into the evaporation-polymerizing chamber 3 which has evaporation sources of the raw material monomers A, B. With the use of such an apparatus for evaporation- polymerization of the raw material monomers to form a polyimide film on a substrate, the gas flow rate controllers 11A, 11B control the feed rates of the raw material monomers A, B gasified in the evaporation sources and feed to the evaporation-polymerizing chamber 3 to form the polyimide film on the substrate through the evaporation-polymerization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus for forming an interlayer insulating film in a semiconductor element by vapor deposition polymerization and a method for forming a polyimide film using the apparatus.

[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
A SiO ₂ film formed by a method D (chemical vapor deposition) is mainly used. The relative dielectric constant of the interlayer insulating film formed by these methods is about 4, but recently, with the progress of high integration of LSI, it has been regarded as a major issue to lower the relative dielectric constant of the interlayer insulating film. An interlayer insulating film having a ratio of 4 or less is required.

[0003] In response to such demands, in recent years, SiOF films or amorphous fluorinated carbon films in which fluorine has been added to an SiO ₂ film formed by a plasma CVD method have been proposed. The relative dielectric constant of the film is about 3.7-3.2 for the former and 2.7-2.3 for the latter.
It can be suppressed to the extent.

[0004]

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

Also, in the case of the above-mentioned amorphous fluorinated carbon film, the film characteristics greatly differ depending on the method of forming the film and the film forming conditions, and it is necessary to sacrifice the heat resistance to achieve a low dielectric constant. For this reason, decomposed gas is likely to be generated at a process temperature (about 400 ° C.) other than the interlayer insulating film forming process, and when a further film is formed on the interlayer insulating film, gas is generated between the layers and the semiconductor element is destroyed. It has been pointed out that this can be a factor.

It has also been proposed to use fluorinated polyimide as a candidate for a material that satisfies heat resistance and a low dielectric constant. A low dielectric constant polyimide can be coated by a vapor deposition polymerization method using a film forming apparatus similar to a conventional CVD method. It became so. However, in this case, it is difficult to precisely control the evaporation amount of the raw material monomer or the supply amount of the monomer to the film forming apparatus, which is not satisfactory.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and forms a low dielectric constant polymer composite film for an interlayer insulating film having stable characteristics in a simple process. It is an object of the present invention to provide a semiconductor manufacturing apparatus and a method for easily forming a polyimide film for an interlayer insulating film in a semiconductor element by vapor deposition polymerization using the apparatus.

[0008]

The semiconductor manufacturing apparatus of the present invention comprises a chamber for loading and unloading wafers, a core chamber having a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers. In a single-wafer semiconductor manufacturing apparatus in which at least one chamber is a vapor deposition polymerization chamber having an evaporation source of a raw material monomer for vapor deposition polymerization, between the vapor deposition polymerization chamber and the raw material monomer evaporation source, the vapor deposition polymerization is performed from the evaporation source. A gas flow controller for controlling the supply amount of the raw material monomer introduced into the chamber is provided.

Further, the method of forming a polyimide film according to the present invention comprises a chamber for loading and unloading a wafer, a core chamber having a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers. In a method of forming a polyamide film using a single-wafer type semiconductor manufacturing apparatus in which a chamber is an evaporation polymerization chamber having an evaporation source of an evaporation polymerization raw material monomer, the raw material monomer is vapor-deposited and polymerized on a substrate in the evaporation polymerization chamber. When a polyimide film is formed by vapor deposition polymerization, the supply rate of the raw material monomer vaporized by the evaporation source is controlled by a gas flow rate controller provided between the vapor deposition polymerization chamber and the raw material monomer evaporation source. And forming a polyimide film on the wafer by vapor deposition polymerization. As a result, a polyimide film having excellent heat resistance and electrical properties and having little variation in properties can be obtained.

In the present invention, the raw material monomer used for forming the polyimide film is not particularly limited, and may be a combination of monomers having low reactivity or a combination of monomers having high reactivity and low vapor pressure. A known raw material monomer for forming a polyimide, for example, 4,4'-diaminodiphenyl ether (ODA), pyromellitic dianhydride (PMDA) or the like may be used. In general, the conditions for vapor deposition polymerization are such that heating and vapor deposition are performed in a high vacuum (1 × 10 ⁻³ Pa or less) such that the composition ratio of both monomers becomes a stoichiometric ratio. However, the substrate temperature differs depending on the type of the monomer.

In general, in a film forming process by vapor deposition polymerization, the reactivity and vapor pressure of a raw material monomer greatly affect the film formation. In the case of a combination of monomers having low reactivity, if the substrate temperature is increased, polymerization occurs under the reaction rate-determining conditions of the monomers, and a film is formed. Therefore, it is not necessary to precisely control the introduction amount of each monomer into the vapor deposition polymerization chamber. However, in the case of a combination of monomers with high reactivity and low vapor pressure, polymerization occurs under the rate-limiting condition of monomer supply and a film is formed, so it is necessary to precisely control the amount of each monomer introduced into the vapor deposition polymerization chamber. become. In vapor deposition polymerization using two or more monomers, as the composition ratio of each monomer is closer to 1: 1, the physical properties such as heat resistance, mechanical properties, and electrical properties of the obtained polymer material are improved. As the composition ratio deviates, the physical properties decrease. In the conventional method, the amount of each monomer introduced into the vapor deposition polymerization chamber was controlled only by the monomer supply amount and the vaporization temperature, so it was difficult to precisely control this method, and the characteristics of the film thus obtained would vary. There were drawbacks.
However, if the amount of each monomer introduced into the vapor deposition polymerization chamber is precisely controlled using a gas flow controller as in the present invention, the variation in the physical properties of the obtained film becomes extremely small.
For example, the variation of the physical properties of the film formed without using the gas flow controller is about ± 10% on average, while the variation of the physical properties of the film formed using the gas flow controller is about ± 3. %, And the physical properties themselves are improved by 5 to 10%.

[0012]

Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of an example of the semiconductor manufacturing apparatus of the present invention, and FIG. 2 shows a schematic configuration of an example of a vapor deposition polymerization chamber forming a part of FIG.

As shown in FIG. 1, in this device,
A core chamber 1 in which a robot for transferring a substrate such as a silicon substrate is incorporated, an L / UL chamber 2 for a substrate such as a silicon substrate, a vapor deposition polymerization chamber (first chamber) 3, a heat treatment chamber (second chamber) 4, and An aluminum sputtering chamber (third chamber) 5 is provided, and the L / UL chamber 2, the first chamber 3, the second chamber 4, and the third chamber 5 are provided around the core chamber 1, respectively. It is configured to be connected via a gate valve 7. In addition,
These chambers are equipped with a vacuum exhaust system such as a vacuum pump (not shown).
It is connected to. A known substrate transfer robot provided in the core chamber 1 is configured to transfer a substrate into an L / UL chamber 2, a vapor deposition polymerization chamber 3, a heat treatment chamber 4, an aluminum sputter chamber 5 around the core chamber.
It is set so that it can be carried in and out of each of these chambers, and can be freely transported from the L / UL chamber to each of these chambers and between these chambers.

As shown in FIG. 2, in the vapor deposition polymerization chamber 3, supply sources of two types of raw material monomers A and B are provided with vaporizers (evaporators) 11a and 11b and a gas flow controller 12a.
a, 12b, so that the vaporized raw material monomer can be introduced into the vapor deposition polymerization chamber. The housings 13a and 13b of the respective monomer supply sources are provided with monomer containers 14a and 14b for the monomers A and B, respectively. Around each container for vaporization such as a heater for heating each monomer, respectively. Heat source 15a,
15b are provided. Supply source (vaporizer 11a, 11
b), the gas flow controllers 12a and 12b and the vapor deposition polymerization chamber 3 are connected, and the introduction pipes 16a and 16b for introducing each monomer into the vapor deposition polymerization chamber are controlled so that the temperature can be controlled by a heat source H such as a heater. Has become. A heater is provided between the connecting portions of the introduction pipes 16a and 16b to the vapor deposition polymerization chamber 3 and the substrate 18 placed on the substrate support member 17 so that each monomer can be uniformly supplied onto the substrate. A monomer mixing tank 19 kept warm by a heat source H is disposed.

Valves 20a and 20b are arranged in the middle of the conduits of the introduction pipes 16a and 16b, and the film thickness can be controlled by opening and closing these valves when forming the vapor-deposited polymerized film.

When a film is formed on the substrate 18 using the above apparatus, the substrate is moved from the L / UL chamber 2 to the vapor deposition polymerization chamber 3 via the core chamber, and then the valves 20a and 20b are opened. Perform the deposition process for a period of time and then
a, 20b are closed, and the substrate is transported to the heat treatment chamber 4. Heat treatment is performed in this heat treatment chamber under predetermined conditions. Generally, the heat treatment is performed by heating to 400 ° C. at a rate of temperature increase of 10 ° C./min, holding at this temperature for 1 hour, and finally cooling naturally. The atmosphere is performed under conditions such as in a high vacuum or in an inert gas. Also, if necessary, the substrate is transferred to the aluminum sputtering 5 chamber,
r: 1000 sccm, 1 × 10 ^-2 Pa, RF power:
2KW, no substrate bias, deposition rate (rate): 5
An aluminum electrode can be formed under conditions such as 0 ° / sec and a film thickness of 200 nm.

Hereinafter, one embodiment of a process for forming an interlayer insulating film of a semiconductor element made of a polyimide film using the apparatus of the present invention will be described.

First, as a semiconductor substrate for forming a polyimide film, a silicon thermal oxide film formed on a substrate surface and having a window opened at a predetermined position, and a silicon thermal oxide film formed thereon and patterned A substrate made of, for example, Si having a first layer wiring is prepared. On the surface of the substrate, a polyimide film is entirely formed to a desired thickness by the above-described vapor deposition method to form an interlayer insulating film. Next, a resist film having a predetermined pattern is formed on the surface of the interlayer insulating film, and ordinary dry etching is performed to remove the interlayer insulating film exposed at a window opening portion of the resist film. Then, after removing the above-described resist film, a wiring thin film is formed on the entire surface and patterned to form a second-layer wiring. By doing so, the first layer wiring and the second layer wiring are electrically connected at the window opening where the interlayer insulating film is removed, and as a result, the semiconductor element having the multilayer wiring is connected. Obtainable.

According to the present embodiment, since the interlayer insulating film is constituted by the polyimide film having a reduced relative dielectric constant,
The capacitance of the capacitor formed between the first-layer wiring and the second-layer wiring is reduced, and the operation speed of the semiconductor element can be improved.

[0020]

EXAMPLES Hereinafter, specific examples of the present invention will be described together with comparative examples.

Example 1 A polyimide film was formed on a substrate as follows using the apparatus shown in FIGS.
First, by using the substrate transfer robot provided in the core chamber 1, the electric conductivity is set to 0.4 from the L / UL chamber 2 via the core chamber 1.
A 6-inch diameter silicon substrate 17 of 02 Ωcm was transported to the vacuum evaporation chamber 3, where a polyimide film was vapor-deposited and polymerized. 4,4'-diaminodiphenyl ether (ODA) as a raw material monomer for forming a polyimide film
And pyromellitic dianhydride (PMDA), and these are supplied to the containers 14a and 14a in the vaporizers 11a and 11b, respectively.
4b and evaporated using heat sources (15a, 15b). ODA was evaporated at a temperature of 158.0 + 0.1 ° C. and PMDA was evaporated at a temperature of 182 + 0.1 ° C. to control the supply of each monomer. Each of the obtained steams is introduced into an inlet pipe 16.
a, 16b through the gas flow controllers 12a, 1
2b, a constant flow rate (for example, 100 sccm) is supplied to the vapor deposition polymerization chamber 3 through the monomer mixing tank 19,
The above was polymerized by vapor deposition. The composition ratio of the monomers was controlled so as to be 1: 1 in stoichiometric ratio.
The inlet tube was kept at a predetermined temperature so that the monomer temperature did not drop during the passage through a and 16b. The deposition polymerization conditions were as follows: substrate temperature: 25 ° C., pressure: 1 × 10 ⁻³ Pa, and film formation rate (rate): 100 ° / sec.

After the film formation in the vapor deposition polymerization chamber 3, the obtained substrate was transferred to the heat treatment chamber 4 via the core chamber 1 by using a substrate transfer robot, and heat-treated. This heat treatment was performed by heating to 350 ° C. at a rate of 5 ° C./min, holding for 30 minutes, and then heating to 400 ° C. at 10 ° C./min. The film thickness at this point was 500 nm.

The above-mentioned film formation and heat treatment process was performed in the same apparatus for one time.
The measurement was performed 0 times, and the ten kinds of polyimide films thus obtained were measured for infrared absorption spectrum, heat resistance, and electric properties. The heat resistance was evaluated by the 5% weight loss temperature of the film, and the electrical properties were evaluated by relative permittivity. In this case, the value of the relative dielectric constant was determined by calculation by measuring the capacitance C using a multi-frequency LCR meter (model 4275A) manufactured by Yokogawa Hewlett-Packard Company.

(Comparative Example 1) In the apparatus used in Example 1, the gas flow controller was not used at the time of vapor deposition polymerization, that is, the supply amount of each monomer was controlled only by the evaporation temperature. Under the same conditions of vapor deposition polymerization and heat treatment, vapor deposition polymerization and heat treatment were performed to form a polyimide film on the substrate. With respect to the obtained film, an infrared absorption spectrum was measured in the same manner as in Example 1;
Heat resistance and relative permittivity were measured.

In the case of Example 1, the polyimide films obtained in the above Examples and Comparative Examples had substantially the same film thickness (variation of ± 2% between batches) and infrared absorption spectra for all 10 types. However, in the case of Comparative Example 1,
The film thickness was highly variable with an average of ± 8%, and the film thickness tended to decrease with repetition. The heat resistance is
In the case of Example 1, the temperature was 523 ± 20 ° C., and the variation was small, but in the case of Comparative Example 1, it was low, 485 ± 50 ° C., and the variation was large. The relative dielectric constant was determined according to Example 1.
In the case of Comparative Example 1, the variation was small, that is, 3.0 ± 0.1, but in the case of Comparative Example 1, it was slightly high, 3.2 ± 0.25, and the variation was large.

[0026]

According to the semiconductor manufacturing apparatus of the present invention, the amount of the monomer introduced into the vapor deposition polymerization chamber is set between the vapor deposition polymerization chamber having the vaporization polymerization raw material monomer evaporation source and the raw material monomer evaporation source. By providing a gas flow controller for controlling, a low relative dielectric constant polymer composite film for an interlayer insulating film having stable physical properties can be easily formed in a simple process.

Further, when a raw material monomer is vapor-deposited and polymerized on a substrate to form a polyimide film using such a semiconductor manufacturing apparatus, the supply rate of the raw material monomer vaporized by the raw material monomer evaporation source is controlled by a gas flow rate controller. Into a vapor deposition polymerization chamber, and a polyimide film can be formed on the substrate by vapor deposition polymerization. Therefore, a low dielectric constant for an interlayer insulating film having stable physical properties (heat resistance and electrical properties) in a simple process. Rate polyimide film can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a schematic configuration of an example of a semiconductor manufacturing apparatus of the present invention.

FIG. 2 is a schematic sectional view showing a schematic configuration of an example of a vapor deposition polymerization chamber constituting a part of the semiconductor manufacturing apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Core room 2 L / UL room 3 Deposition polymerization room 4 Heat treatment room 5 Aluminum sputter room 6 Gate valve 11a, 11b Vaporizer 12a, 12b
Gas flow controller 13a, 13b Housing 14a, 14b
Monomer container 15a, 15b Heat source for vaporization 16a, 16b
Introduction pipe 17 Substrate support member 18 Substrate 19 Monomer mixing tank 20a, 20b
Valve A, B Monomer H Heat source

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshiyuki Ukishima 5-9-7 Tokodai, Tsukuba, Ibaraki Pref. TB01 UA122 UA131 UA662 UA672 UB121 VA021 VA041 XA07 XA40 XB39 XB40 ZA43 ZA46 4K030 BA35 CA04 CA12 FA10 GA12 JA05 KA41 5F031 CC11 KK07 LL02 5F045 AA03 AB39 AC07 DC63 DQ17 EB08 EE04 A0201

Claims (2)

[Claims] 1. A chamber for loading and unloading wafers, a core chamber having a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, wherein at least one of the process chambers is an evaporation source of a raw material monomer for vapor deposition polymerization. In a single-wafer semiconductor manufacturing apparatus which is a vapor deposition polymerization chamber having, between the vapor deposition polymerization chamber and the raw material monomer evaporation source, the supply amount of the raw material monomer introduced into the vapor deposition polymerization chamber from the evaporation source is controlled. A semiconductor manufacturing apparatus, comprising a gas flow controller for controlling the semiconductor flow. 2. A semiconductor device comprising a chamber for loading and unloading wafers, a core chamber having a wafer transfer robot, and a plurality of semiconductor manufacturing process chambers, wherein at least one of the process chambers is an evaporation source of a raw material monomer for vapor deposition polymerization. In the method of forming a polyamide film using a single-wafer type semiconductor manufacturing apparatus which is a vapor deposition polymerization chamber having a vapor deposition polymerization chamber, the raw material monomers are vapor-deposited and polymerized on a substrate in the vapor deposition polymerization chamber to form a polyimide film. A gas flow controller provided between the polymerization chamber and the raw material monomer evaporation source controls the supply amount of the raw material monomer vaporized by the evaporation source, introduces the raw material monomer into the vapor deposition polymerization chamber, and vapor-deposits on the wafer. A method for forming a polyimide film, comprising forming a polyimide film by polymerization.