JP5007487B2 - Spin coating method, low dielectric constant interlayer insulating film manufacturing method, and semiconductor device manufacturing method - Google Patents

Description

The present invention is a spin coating method, a method of manufacturing a low dielectric constant interlayer insulating film, and relates to a method of manufacturing a semiconductor device, in particular, the relative dielectric constant by using a single material supply nozzle and a single spin-coating material A spin coating method, a low dielectric constant interlayer insulating film manufacturing method , and a semiconductor device manufacturing method characterized by a structure for forming a film having different physical properties such as strength and etching rate Is.

  Conventionally, it has been known that the signal propagation speed is lowered due to the parasitic capacitance of the insulating film. However, in the generation in which the wiring interval of the semiconductor device is 1 μm or more, the influence of the wiring delay on the entire device is small. However, as the wiring interval becomes 1 μm or less, the influence on the device speed is increasing.

  Along with the recent increase in the degree of integration of semiconductor integrated circuits and the improvement in device density, the demand for multi-layered semiconductor devices is increasing. Wiring delay due to the increase has become a problem, and in particular, when a circuit is formed with a wiring interval of 100 nm or less in the future, parasitic capacitance between wirings greatly affects the device speed.

The wiring delay T due to the parasitic capacitance between the wirings is affected by the wiring resistance R and the capacitance C between the wirings, and is expressed by the following formula (1).
T∝CR (1)

The capacitance C between the wirings in this case is _expressed by the following equation (2), where S is the wiring area, ε ₀ is the vacuum dielectric constant, ε _r is the relative dielectric constant of the insulating film, and d is the wiring spacing. .
C = ε ₀ ε _r S / d (2)

  Therefore, in order to reduce the wiring delay T, it is an effective means to reduce the dielectric constant of the insulating film. For this purpose, the dielectric constant is lowered by introducing holes in the insulating film or using an organic material. Low dielectric constant interlayer insulating films have been tried.

  On the other hand, the semiconductor device formation process includes several stressful processes such as a CMP (chemical mechanical polishing) process for forming a copper wiring and a wire bonding process for taking an electrode from a pad. Insulating films have low strength due to the introduction of vacancies in the insulating film and the use of organic insulating films in order to reduce the dielectric constant. It contributes to the decline.

  In other words, the low dielectric constant interlayer insulation film that introduces holes in the insulation film or employs an organic insulation film breaks down the low dielectric constant interlayer insulation film during the CMP process for copper wiring formation or wire bonding to the electrode. There is a problem of being done.

  On the other hand, a spin coating method (for example, see Patent Document 1) has been conventionally known as a method for forming a relatively high strength low dielectric constant insulating film. In such a spin coating method, an atmosphere in the spin coating is known. Attempts have been made to eliminate non-uniformity within the spin coat thin film and between wafers by saturating the substrate with a solvent or the like contained in the raw material. Uniformity can be reduced.

  In order to satisfy the required characteristics, a method of obtaining a desired thin film by using a sol-gel method or the like and performing a chemical reaction during spin coating has been realized.

Here, a method of forming a low dielectric constant insulating film by a conventional spin coating method will be described with reference to FIG.
See FIG.
FIG. 11 is a conceptual configuration diagram of a general spin coater. For example, a wafer 57 is held and fixed in a stainless steel chamber 51 including an atmosphere supply pipe 52, an exhaust pipe 53, and a filter 54. A spindle motor 55 having a wafer chuck 56 is accommodated, and a material having excellent chemical resistance, for example, a spin coater cup 58 having an open upper surface made of Teflon (registered trademark) is provided so as to surround the wafer chuck 56. An exhaust port 59 and a drainage pipe 60 are provided below the spin coater cup 58.

In addition, a spin coat material supply nozzle 61 is provided so as to face the open portion of the upper surface of the spin coater cup 58. The spin coat material is dropped onto the wafer 57 from the spin coat material supply nozzle 61 and an atmosphere supply pipe 52 is provided. Then, atmospheric gas is introduced into the spin coater cup 58 and the spindle motor 55 is rotated to form a coating film on the wafer 57.
In this case, in order to eliminate as much as possible the influence of the atmosphere in the spin coater cup that performs spin coating, the spin coating is performed with the humidity in the spin coater cup kept constant.

Next, an example of a method for forming a low dielectric constant silicon oxide film will be described. First,
Tetraethoxysilane 20.8g (0.1mol)
17.8 g (0.1 mol) of methyltriethoxysilane
23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane
Methyl isobutyl ketone 39.6g
200 ml of a solution having the composition ratio was charged into a reaction vessel, and 16.2 g (0.9 mol) of a 1% tetramethylammonium hydroxide aqueous solution was added dropwise for 10 minutes, and a ripening reaction was performed for 2 hours after completion of the addition.

  Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml, and then 20 ml of methyl isobutyl ketone was added to the resulting reaction solution. This was added to prepare a porous silica precursor coating solution for the wiring separation layer.

The prepared porous silica precursor coating solution is dropped from the spin coating material supply nozzle 61 onto the wafer 57, spin-coated, pre-baked at 200 ° C. for 3 minutes, and then subjected to 400 in an electric furnace in an N ₂ gas atmosphere. A silicon oxide film was formed by curing at 30 ° C. for 30 minutes.
Here, a low resistance substrate was used as the wafer 57 in order to measure the relative dielectric constant of the obtained low dielectric constant silicon oxide film.

The relative dielectric constant ε _r of the obtained silicon oxide film was calculated from the capacitance measured with a mercury probe, and found to be 2.4.
Moreover, when the intensity | strength of the silicon oxide film obtained using nanoindenter (brand name made from MTS Systems) was measured, Young's modulus was 7.3 GPa and hardness was 0.8 GPa.
Further, when the film thickness was measured by 49 points using a spectroscopic ellipsometer, the average value was 174.75 nm and 3σ was 3.1 nm.
JP 2000-279874 A

  However, with such a spin coating method, it is difficult to form a low dielectric constant silicon oxide film that can sufficiently satisfy the low dielectric constant and the strength along the semiconductor road map.

  Therefore, in the future, spin coating thin films will be required to have higher properties. However, the current method can only change the drying rate even if the atmosphere is controlled during the reaction. There is a problem that it is difficult to control and the characteristics cannot be fully extracted.

  Also, with the current spin coater, only one type of material can be deposited per one spin coat material supply nozzle, and the number of steps or cost when depositing a multilayer structure film composed of different thin films is reduced. There is a problem of growing.

  Further, in the material development, since it is necessary to recreate the spin coat material after the result is obtained and replace the material in the coater, there is a problem that time and cost for feedback are large.

  Furthermore, once a film forming condition including a spin coat material is set in the product production process, there is a problem that the difference between lots of materials cannot be corrected.

  Therefore, an object of the present invention is to form an insulating film excellent in mechanical strength, relative dielectric constant, or film adhesion with a simple apparatus configuration.

FIG. 1 is a diagram illustrating the basic configuration of the present invention. Means for solving the problems in the present invention will be described with reference to FIG.
See FIG. 1 In order to solve the above-mentioned problem, the present invention is characterized in that in a spin coating method, a material that reacts with the spin coating material 3 is introduced into the spin coater cup 1 in a gas phase state during the spin coating. .

In this way, by introducing a material that reacts with the spin coat material 3 during spin coating into the spin coater cup 1 in a gas phase state, the characteristics of the thin film formed on the substrate 1 can be greatly changed.

  That is, in the conventional case, the reaction during spin coating, that is, the characteristics of the formed film are almost determined only by the material composition, but in the present invention, by controlling the reaction during spin coating, for example, Thus, a low dielectric constant thin film having both low dielectric constant and high strength can be formed.

Such a method is suitable when the spin coating material 3 is the spin coating material 3 that is formed by advancing chemical reaction during spin coating, and is introduced into the spin coater cup 1 in this state in a gas phase. The reaction can be suppressed by using a material generated when the spin coating material 3 is polymerized as the material, that is, the gas phase material 4.

  For example, when a material using alkoxysilane as a raw material is used as the spin coating material 3, the reaction can be suppressed by using alcohol as the vapor phase material 4.

Alternatively, the reaction can be promoted by using a material consumed when the spin coat material 3 is polymerized as the vapor phase material 4 introduced into the spin coater cup 1. For example, the spin coat material 3 is an alkoxysilane. The reaction can be promoted by using water as the gas phase material 4.
Conversely, when the partial pressure of water vapor, that is, humidity is reduced, the reaction is suppressed.

  Further, the concentration of the vapor phase material 4 in the spin coater cup 1 is controlled to control the reaction. For example, the concentration of the vapor phase material 4 in the spin coater cup 1 is controlled over time to form a film. Accordingly, a multilayer structure having different characteristics can be formed in a series of film forming steps.

  Further, the concentration of the vapor phase material 4 in the spin coater cup 1 may be controlled by being mixed in the atmospheric gas, or may be introduced from a gas inlet provided inside the chamber and outside the spin coater cup 1. Although it is good, in order to control the concentration with high accuracy, it is desirable to introduce the gas directly from the gas inlet provided in the spin coater cup 1.

  An insulating film having a low dielectric constant and a high strength can be formed by film formation using the spin coating method described above, and an arbitrary dielectric constant and strength can be obtained by controlling the concentration of the vapor phase material 4. It is possible to form an insulating film having an arbitrary profile in the stacking direction.

  That is, by using a plurality of atmosphere concentration control recipes, for example, when a low dielectric constant thin film is formed from the same spin coat material 3, the dielectric constant and strength in a trade-off relationship are increased, and in some cases, the dielectric constant is increased. In other cases, it is possible to form the film so as to increase the strength.

  Furthermore, by changing the atmosphere introduction timing, the reaction of the introduced gas to the spin coating material 3 can be performed without changing in the thickness direction of the thin film, by changing in the thickness direction, and only near the surface. It becomes possible to make it.

  Further, by providing such a multilayer wiring structure using the low dielectric constant interlayer insulating film, the wiring delay T in the highly integrated semiconductor device can be greatly reduced.

  According to the present invention, even when a single spin coating material is used, an interlayer insulating film having an arbitrary relative dielectric constant or strength can be obtained, thereby reducing the low dielectric constant of the low dielectric constant interlayer insulating film. It is possible to form a high-speed semiconductor integrated circuit device that has both strength and strength enough to withstand integration.

  In the present invention, when a film is applied on a substrate by a spin coating method, a material that reacts with the spin coating material is introduced into the spin coater cup in a gas state during the spin coating to control the reaction of the spin coating material. The relative dielectric constant, film density, strength, or film adhesion of the film is controlled.

  The material to be introduced into the spin coater cup in the gas state in this case is not particularly limited as long as it is a material that reacts with the spin coat material during spin coating. For example, ozone, oxygen, carbon monoxide, formaldehyde, ammonia And reactive materials such as hydrogen chloride.

  When ozone, oxygen, or carbon monoxide is introduced, the oxidation of the film is promoted to increase the film density, or the hydrophilicity of the film surface is increased to improve the adhesion with the film formed thereon. Moreover, since formaldehyde has a reducing property, oxidation of the film is suppressed, and furthermore, ammonia or hydrogen chloride can control the reaction by adjusting the pH in the atmosphere.

  Further, a sol-gel method is used as a spin coating material, for example, a tetraalkoxysilane material such as tetramethoxysilane or tetraethoxysilane, or an alkyl such as methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, or trimethylmethoxysilane. When materials using alkoxysilane materials as monomers are used, water that promotes the reaction, and methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, and tertiary butyl alcohol that suppress the reaction are used. An alcohol type is mentioned.

  In addition, in order to introduce a material that reacts with the spin coat material into the spin coater cup in a gaseous state, a reaction control gas introduction nozzle may be provided outside the spin coater cup, or a normal atmosphere supply pipe may be provided. Equilibrium reaction control gas may be introduced with a mass flow controller or the like. However, in order to control the concentration in the spin coater cup during spin coating with high accuracy and efficiency, a gas inlet is provided in the spin coater cup for reaction. It is desirable to introduce a control gas introduction nozzle.

In this case, when supplying a liquid reaction-suppressing material in a gaseous state at room temperature, an inert gas such as N ₂ , Ar, CO ₂ or the like is used as a carrier gas in order to control the concentration in the spin coater cup accurately and efficiently. It may be introduced together with an inert gas.

Next, the spin coating method of Example 1 of the present invention will be described with reference to FIG.
See Figure 2
FIG. 2 is a conceptual configuration diagram of a spin coater used in the spin coat method of Example 1 of the present invention, in which a reaction control gas introduction pipe is provided in the middle of an atmosphere supply pipe of a conventional spin coater. A spindle motor 16 having a wafer chuck 17 for holding and fixing a wafer 18 in a stainless steel chamber 11 having a reaction control gas introduction pipe 13 and an atmosphere supply pipe 12, an exhaust pipe 14, and a filter 15. There is provided a spin coater cup 19 made of Teflon (registered trademark) having an open upper surface, which is housed and has excellent chemical resistance so as to surround the wafer chuck 17. On the side, an exhaust port 20 and a drain pipe 21 are provided.

  In addition, a spin coat material supply nozzle 22 is provided so as to face the open portion of the upper surface of the spin coater cup 19, and the spin coat material is dropped onto the wafer 18 from the spin coat material supply nozzle 22, and the atmosphere supply tube 12. Then, an atmosphere gas is introduced into the spin coater cup 19 together with the reaction suppression gas supplied from the reaction control gas introduction pipe 13, and the spindle motor 16 is rotated to form a coating film on the wafer 18.

Next, a method for forming a low dielectric constant silicon oxide film in Example 1 of the present invention will be described. First, as in the conventional case,
Tetraethoxysilane 20.8g (0.1mol)
17.8 g (0.1 mol) of methyltriethoxysilane
23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane
Methyl isobutyl ketone 39.6g
In a 200 ml reaction vessel, 16.2 g (0.9 mol) of a 1% tetramethylammonium hydroxide aqueous solution was added dropwise for 10 minutes, and an aging reaction was carried out for 2 hours after completion of the addition.

  Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml, and then 20 ml of methyl isobutyl ketone was added to the resulting reaction solution. This was added to prepare a porous silica precursor coating solution for the wiring separation layer.

Next, ethanol is introduced into the spin coater cup 19 from the reaction control gas introduction pipe 13 attached to the atmosphere supply pipe 12, and the temperature inside the spin coater cup is 23 ° C., the humidity inside the spin coater cup is 45%, and the vapor pressure of ethanol is 52.5 mmHg. Then, the prepared porous silica precursor coating solution is dropped onto the wafer 18 from the spin coating material supply nozzle 22 and spin coated.
The humidity 45% is the humidity in the clean room.

Next, as in the conventional case, after pre-baking at 200 ° C. for 3 minutes, curing was performed at 400 ° C. for 30 minutes in an electric furnace in an N ₂ gas atmosphere to form a silicon oxide film.
Also in this case, a low resistance substrate was used as the wafer 18 in order to measure the relative dielectric constant of the obtained low dielectric constant silicon oxide film.

The relative dielectric constant ε _r of the obtained silicon oxide film was calculated from the capacitance measured with a mercury probe, and was 2.25, and a silicon oxide film having a relative dielectric constant lower by 10% or more than the conventional one was obtained.
Further, when the strength of the silicon oxide film obtained using a nanoindenter (trade name, manufactured by MTS Systems) was measured, the Young's modulus was 9.2 GPa, the hardness was 1.0 GPa, and both the Young's modulus and hardness were 20% or more. An improvement was observed, and a silicon oxide film that could withstand the CMP process and the like was obtained.
When the film thickness was measured with a spectroscopic ellipsometer at 49 points, the average value was 170.23 nm and 3σ was 2.9 nm.

  As described above, in Example 1 of the present invention, since ethanol generated by the reaction of the spin coat material during the spin coating is introduced into the atmosphere, the reaction of the spin coat material is suppressed and the film is uniform. Thus, a high strength film was obtained, and an insulating film having a low relative dielectric constant was obtained.

Next, the spin coating method of Example 2 of the present invention will be described with reference to FIGS.
See Figure 3
FIG. 3 is a conceptual configuration diagram of a spin coater used in the spin coat method of Embodiment 2 of the present invention, in which a humidity adjusting port and an ethanol concentration adjusting port are provided in a spin coater cup of a conventional spin coater. .

  That is, the spin coater used in the spin coat method of the second embodiment of the present invention is a wafer for holding and fixing a wafer 18 in a stainless steel chamber 11 provided with an atmosphere supply pipe 12, an exhaust pipe 14, and a filter 15. A spindle motor 16 having a chuck 17 is accommodated, and a spin coater cup 19 having an open upper surface made of a material having excellent chemical resistance, for example, Teflon (registered trademark), is provided so as to surround the wafer chuck 17. An exhaust port 20 and a drain pipe 21 are provided below the spin coater cup 19, and a humidity adjusting port 23 and an ethanol concentration adjusting port 24 are provided on the upper side wall of the spin coater cup 19.

  In addition, a spin coat material supply nozzle 22 is provided so as to face the open portion of the upper surface of the spin coater cup 19, and the spin coat material is dropped onto the wafer 18 from the spin coat material supply nozzle 22, and the atmosphere supply tube 12. Then, an atmosphere gas is introduced into the spin coater cup 19 together with the reaction suppression gas supplied from the reaction control gas introduction pipe 13, and the spindle motor 16 is rotated to form a coating film on the wafer 18.

Next, a method for forming a low dielectric constant silicon oxide film in Example 2 of the present invention will be described. First, as in the prior art,
Tetraethoxysilane 20.8g (0.1mol)
17.8 g (0.1 mol) of methyltriethoxysilane
23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane
Methyl isobutyl ketone 39.6g
In a 200 ml reaction vessel, 16.2 g (0.9 mol) of a 1% tetramethylammonium hydroxide aqueous solution was added dropwise for 10 minutes, and an aging reaction was carried out for 2 hours after completion of the addition.

  Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml, and then 20 ml of methyl isobutyl ketone was added to the resulting reaction solution. This was added to prepare a porous silica precursor coating solution for the wiring separation layer.

See Figure 4
Next, in a state where ethanol is introduced into the spin coater cup 19 from the ethanol concentration adjusting port 24, the temperature inside the spin coater cup is 23 ° C., the humidity inside the spin coater cup is 45%, and the vapor pressure of ethanol is 52.5 mmHg. The porous silica precursor coating solution is dropped onto the wafer 18 from the spin coat material supply nozzle 22.

  Next, while dripping the porous silica precursor coating solution as shown in FIG. 4, the humidity in the spin coater cup becomes 30% after 3.4 seconds from the start of dropping, and then continues to maintain the humidity of 30% for 14 seconds, Thereafter, it is returned to 45% again over 15 seconds, and the humidity of the supply gas from the humidity adjusting port 23 is controlled so as to be substantially equal to the humidity in the clean room.

  The ethanol partial pressure is controlled by maintaining ethanol at 52.5 mmHg until 17.4 seconds after the start of dropping, and then introducing ethanol from the ethanol concentration adjusting port 24 so that it becomes 10 mmHg over 15 seconds.

Next, as in the conventional case, after pre-baking at 200 ° C. for 3 minutes, curing was performed at 400 ° C. for 30 minutes in an electric furnace in an N ₂ gas atmosphere to form a silicon oxide film.
Also in this case, a low resistance substrate was used as the wafer 18 in order to measure the relative dielectric constant of the obtained low dielectric constant silicon oxide film.

The relative dielectric constant ε _r of the obtained silicon oxide film was calculated from the capacitance measured with a mercury probe, and was 2.27, and the silicon oxide film obtained using a nanoindenter (trade name, manufactured by MTS Systems) When the strength was measured, the Young's modulus was 9.3 GPa, the hardness was 1.0 GPa, a low relative dielectric constant compared to the prior art, and an oxidation that can sufficiently withstand the CMP process, etc., which is stronger than the first embodiment. A silicon film was obtained.
When the film thickness was measured at 49 points using a spectroscopic ellipsometer, the average value was 171.51 nm and 3σ was 1.4 nm.

  In Example 2 of the present invention, ethanol that suppresses the reaction is introduced and water that promotes the reaction, that is, water vapor is reduced, so that the reaction can be further suppressed. A large oxide film can be formed.

  In Example 2, the reaction itself was almost completed by 17.4 seconds after dropping, so that the humidity was returned to approximately the same humidity as in the clean room in 17.4 seconds, and the ethanol flow rate that was no longer needed was changed to ethanol. In order to stably supply with good reproducibility when continuously forming the film, the thickness is set to 10 mmHg in the vicinity of the minimum flow rate.

Next, the spin coating method of Example 2 of the present invention will be described with reference to FIGS.
See Figure 5
FIG. 5 is a conceptual configuration diagram of a spin coater used in the spin coat method of Example 3 of the present invention, and a humidity adjustment port, an ethanol concentration adjustment port, and an ozone concentration adjustment in a spin coater cup of a conventional spin coater. A mouth is provided.

  That is, the spin coater used for the spin coat method of the third embodiment of the present invention is a wafer for holding and fixing a wafer 18 in a stainless steel chamber 11 having an atmosphere supply pipe 12, an exhaust pipe 14 and a filter 15. A spindle motor 16 having a chuck 17 is accommodated, and a spin coater cup 19 having an open upper surface made of a material having excellent chemical resistance, for example, Teflon (registered trademark), is provided so as to surround the wafer chuck 17. An exhaust port 20 and a drain pipe 21 are provided below the spin coater cup 19, and a humidity adjusting port 23, an ethanol concentration adjusting port 24, and an ozone concentration adjusting port 25 are provided on the upper side wall of the spin coater cup 19. Provide.

In addition, a spin coat material supply nozzle 22 is provided so as to face the open part of the upper surface of the spin coater cup 19. Then, a reaction suppression gas is supplied from the ethanol concentration adjusting port 24 and the spindle motor 16 is rotated to form a coating film on the wafer 18, and O ₃ is introduced from the ozone concentration adjusting port 25 into the spin coater cup 19 and applied. Promotes film oxidation.

Next, a method for forming a low dielectric constant silicon oxide film in Example 3 of the present invention will be described. First, as in the conventional case,
Tetraethoxysilane 20.8g (0.1mol)
17.8 g (0.1 mol) of methyltriethoxysilane
23.6 g (0.1 mol) of glycidoxypropyltrimethoxysilane
Methyl isobutyl ketone 39.6g
In a 200 ml reaction vessel, 16.2 g (0.9 mol) of a 1% tetramethylammonium hydroxide aqueous solution was added dropwise for 10 minutes, and an aging reaction was carried out for 2 hours after completion of the addition.

  Next, 5 g of magnesium sulfate was added to remove excess water, and then the ethanol produced by the aging reaction was removed with a rotary evaporator until the reaction solution reached 50 ml, and then 20 ml of methyl isobutyl ketone was added to the resulting reaction solution. This was added to prepare a porous silica precursor coating solution for the wiring separation layer.

See FIG.
Next, in a state where ethanol is introduced into the spin coater cup 19 from the ethanol concentration adjusting port 24, the temperature inside the spin coater cup is 23 ° C., the humidity inside the spin coater cup is 45%, and the vapor pressure of ethanol is 52.5 mmHg. The porous silica precursor coating solution is dropped onto the wafer 18 from the spin coat material supply nozzle 22.

Next, as shown in FIG. 6, the supply of O ₃ from the ozone concentration adjusting port 25 is started 3.4 seconds after the start of dropping of the porous silica precursor coating solution, and after 2 seconds, the supply is made 2%, and then 15 seconds. The flow rate of O ₃ is controlled so that it becomes 0%.

Next, as in the conventional case, after pre-baking at 200 ° C. for 3 minutes, curing was performed at 400 ° C. for 30 minutes in an electric furnace in an N ₂ gas atmosphere to form a silicon oxide film.
Also in this case, a low resistance substrate was used as the wafer 18 in order to measure the relative dielectric constant of the obtained low dielectric constant silicon oxide film.

The relative dielectric constant ε _r of the obtained silicon oxide film was calculated from the capacitance measured with a mercury probe, and was 2.53. Also, the silicon oxide film obtained using a nanoindenter (trade name, manufactured by MTS Systems) When the strength was measured, the Young's modulus was 17.3 GPa and the hardness was 1.8 GPa, and a silicon oxide film having a significantly improved strength as compared with the conventional one was obtained.
When the film thickness was measured with a spectroscopic ellipsometer at 49 points, the average value was 204.67 nm, and 3σ was 6.2 nm.

In Example 3 of the present invention, since O ₃ that promotes oxidation of the coating film is introduced, the relative permittivity is increased, but the strength can be greatly increased. In this case, Since the film density increases, it can also be used as an etching stopper.

In addition, since the surface treatment with O ₃ increases the hydrophilicity of the coating surface, the adhesion with the coating film deposited thereon can be improved, and even when a stressful treatment such as CMP is performed, Peeling can be prevented.

  Next, a spin coating method according to a fourth embodiment of the present invention will be described with reference to FIG. 7, but the spin coating method itself is exactly the same as the first embodiment described above, except that the configuration of the spin coating apparatus is different. Therefore, only the spin coater will be described.

See FIG.
FIG. 7 is a conceptual configuration diagram of a spin coater used in the spin coat method according to the fourth embodiment of the present invention. In a stainless steel chamber 11 having an atmosphere supply pipe 12, an exhaust pipe 14, and a filter 15. A spindle motor 16 having a wafer chuck 17 for holding and fixing the wafer 18 is accommodated, and an upper surface made of a material having excellent chemical resistance, for example, Teflon (registered trademark) is opened so as to surround the wafer chuck 17. The spin coater cup 19 is provided, an exhaust port 20 and a drain pipe 21 are provided below the spin coater cup 19, and a reaction control gas introduction pipe 26 is provided outside the spin coater cup 19.

  In addition, a spin coat material supply nozzle 22 is provided so as to face the open portion of the upper surface of the spin coater cup 19. The spin coat material is dropped onto the wafer 18 from the spin coat material supply nozzle 22 and a reaction control gas is introduced. The spindle motor 16 is rotated while supplying ethanol, which is a reaction suppressing gas, from the tube 26 to form a coating film on the wafer 18.

  As described above, in the fourth embodiment of the present invention, since the reaction control gas introduction pipe 26 is separately used outside the spin coater cup, the configuration of the spin coater cup 19 is changed or the configuration of the atmosphere supply pipe 11 is changed. There is no need.

  That is, when the chamber 11 is a chamber having a plurality of ports including the view port, it is not necessary to change the entire apparatus configuration by inserting the reaction control gas introduction pipe 26 from one of the ports.

Next, a method for forming a multilayer wiring structure of Example 5 using the spin coating method of the present invention will be described with reference to FIG.
Refer to FIG. 8. First, a groove is provided in the first interlayer insulating film 32 provided on the base insulating film 31, and Cu is buried in the groove. Then, the first embedded Cu wiring layer 33 is polished by CMP. On the formed substrate, first, the via forming insulating film 34 having a relatively high dielectric constant but high strength is formed as in the third embodiment by using the spin coater of the third embodiment.

  Next, after forming a via hole reaching the first embedded Cu wiring layer 33, it is filled with W through a TiN film (not shown) serving as a barrier metal, and then polished by CMP to form a via 35.

  Next, using the same spin coat apparatus and the same porous silica precursor coating solution as in the above-described via formation insulating film 34, only ethanol is introduced and the strength is relatively low, as in Example 1 above. However, a low dielectric constant second interlayer insulating film 36 is formed.

Next, the via 35 is reached and a groove to be a predetermined wiring pattern is formed. Cu is buried in the groove through a TiN film (not shown) serving as a barrier metal, and then polished and planarized by a CMP method. Thus, a second embedded Cu wiring layer 37 is formed, and then a TiN film (not shown) serving as a barrier metal is provided so as to cover the second embedded Cu wiring layer 37.
Thereafter, a highly integrated semiconductor device can be obtained by repeating the above steps for the required number of layers.

  Thus, in Example 5 of the present invention, an interlayer insulating film having different characteristics using the same spin coater and the same porous silica precursor coating solution by simply introducing the reaction control gas and controlling the reaction atmosphere. Since only one apparatus is required and only one kind of spin coating material is prepared, the cost can be reduced.

Next, a method for forming a multilayer wiring structure of Example 6 using the spin coating method of the present invention will be described with reference to FIG.
See FIG.
First, a substrate in which a first embedded Cu wiring layer 33 is formed by providing a groove in the first interlayer insulating film 32 provided on the base insulating film 31 and embedding Cu in the groove, followed by polishing by CMP. Furthermore, using the spin coat apparatus of the above-described third embodiment, first, the via forming insulating film 34 having a relatively high dielectric constant but a high strength is formed as in the third embodiment.

Next, an oxide film having a high film density is formed by increasing the amount of O ₃ introduced compared to the film formation conditions for the via formation insulating film 34 to form a CMP resistant layer 38.

  Next, the CMP resistant layer 38 and the via formation insulating film 34 are sequentially etched to form a via hole reaching the first embedded Cu wiring layer 33, and then buried with W through a TiN film (not shown) serving as a barrier metal. Next, polishing is stopped by the CMP method when the CMP resistant layer 38 is exposed, and the via 35 is formed.

  Next, using the same spin coat apparatus and the same porous silica precursor coating solution as in the above-described via formation insulating film 34, only ethanol is introduced and the strength is relatively low, as in Example 1 above. However, a low dielectric constant second interlayer insulating film 36 is formed.

Next, the second interlayer insulating film 36 is selectively etched using the CMP resistant layer 38 as a stopper to form a trench that becomes a predetermined wiring pattern, and then a TiN film (not shown) that becomes a barrier metal is formed in the trench. Then, after Cu is buried, the second buried Cu wiring layer 37 is formed by polishing and flattening by a CMP method, and then TiN serving as a barrier metal so as to cover the second buried Cu wiring layer 37. A film (not shown) is provided.
Thereafter, a highly integrated semiconductor device can be obtained by repeating the above steps for the required number of layers.

  As described above, in Example 6 of the present invention, the CMP resistant layer and the interlayer insulating film can be obtained using the same spin coater and the same porous silica precursor coating solution by simply introducing the reaction control gas and controlling the reaction atmosphere. And can be formed.

Next, a method for forming a multilayer wiring structure of Example 7 using the spin coating method of the present invention will be described with reference to FIG.
See FIG.
First, a substrate in which a first embedded Cu wiring layer 33 is formed by providing a groove in the first interlayer insulating film 32 provided on the base insulating film 31 and embedding Cu in the groove, followed by polishing by CMP. Furthermore, using the spin coat apparatus of the above-described third embodiment, first, the via forming insulating film 34 having a relatively high dielectric constant but a high strength is formed as in the third embodiment.

  Next, after forming a via hole reaching the first embedded Cu wiring layer 33, it is filled with W through a TiN film (not shown) serving as a barrier metal, and then polished by CMP to form a via 35.

  Next, using the same spin coat apparatus and the same porous silica precursor coating solution as in the above-described via formation insulating film 34, only ethanol is introduced and the strength is relatively low, as in Example 1 above. However, a low dielectric constant second interlayer insulating film 36 is formed.

Subsequently, O ₃ is introduced into the spin coater to make the surface of the second interlayer insulating film 36 hydrophilic to form a hydrophilic layer 39.

Next, the via 35 is reached and a groove to be a predetermined wiring pattern is formed. Cu is buried in the groove through a TiN film (not shown) serving as a barrier metal, and then polished and planarized by a CMP method. Thus, a second embedded Cu wiring layer 37 is formed, and then a TiN film (not shown) serving as a barrier metal is provided so as to cover the second embedded Cu wiring layer 37.
Thereafter, a highly integrated semiconductor device can be obtained by repeating the above steps for the required number of layers.

  As described above, in Example 7 of the present invention, the surface of the second interlayer insulating film 36 is made hydrophilic simply by introducing the reaction control gas and controlling the reaction atmosphere. When the third interlayer insulating film 40 is formed, the adhesiveness with the third interlayer insulating film 40 is enhanced, so that even if stress is applied in the CMP process for forming the via 41, peeling is less likely to occur.

  Many of the low dielectric constant insulating films currently used introduce organic functional groups into the material in order to lower the dielectric constant, but the organic functional groups have low hydrophilicity and adhesion between the insulating films. However, in order to increase hydrophilicity, the hydrophilic treatment was performed using a cleaning device or the like. However, in this Example 7, since the hydrophilic treatment can be performed using the film forming device itself, the manufacturing process is Simplify and improve throughput.

  The embodiments of the present invention have been described above, but the present invention is not limited to the conditions and configurations described in the embodiments, and various modifications are possible. For example, the shape of the reaction control gas inlet Is not particularly limited, and may be a nozzle type, a slit type, or other shapes.

  Further, a sol-gel method is used as a spin coating material, for example, a tetraalkoxysilane material such as tetramethoxysilane or tetraethoxysilane, or an alkyl such as methyltrimethoxysilane, methyltriethoxysilane, dimethyldimethoxysilane, or trimethylmethoxysilane. In the case of using a material whose alkoxysilane material is a monomer, ethanol that suppresses the reaction, that is, alcohol such as methyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, and tertiary butyl alcohol instead of ethyl alcohol. The system may be used as a reaction control gas.

  Further, the reaction control gas is not limited to alcohols, and is not particularly limited as long as it is a material that reacts with the spin coat material during spin coating, promotes oxidation of the film, increases the film density, or In addition, an oxidizing gas such as ozone, oxygen, carbon monoxide or the like that increases the hydrophilicity of the coating surface may be used.

  Furthermore, the reaction control gas is not limited to alcohols, but is formaldehyde that has reducibility and suppresses oxidation of the film, and ammonia or hydrogen chloride that can control the reaction by adjusting the pH in the atmosphere. Etc. may be used.

Also, when supplying a liquid reaction-suppressing material in a gaseous state at room temperature, N ₂ , Ar, CO _2, etc. using an inert gas as a carrier gas in order to control the concentration in the spin coater cup with accuracy and efficiency It may be introduced by mixing with an inert gas.

In Example 6 described above, the O ₃ concentration in the atmosphere is increased in order to form the CMP resistant layer. However, the concentration is not limited to O ₃ , and oxidation of Cl ₂ , H ₂ O _2, etc. A gas capable of increasing the density of the film and increasing the hardness may be introduced, and this CMP resistant layer also serves as an etching stopper because of its low etching rate with respect to a normal SiO ₂ etching solution.

The detailed features of the present invention will be described again with reference to FIG. 1 again.
See FIG. 1 again. (Supplementary Note 1) A spin coating method, wherein a material that reacts with the spin coating material 3 is introduced into the spin coater cup 1 in a gas phase state during the spin coating.
(Supplementary Note 2) spin coating method of statement 1, characterized in that deposition by controlling the concentration of the material to be introduced in the gaseous state in the spin coater cup 1.
(Supplementary Note 3) spin-coating method according to Appendix 2 of the control of the concentration of the material to be introduced in the gaseous state in the spin coater cup 1, and performs over time varied.
(Supplementary Note 4) The control of the concentration of the material to be introduced in the gaseous state in a spin coater cup 1, Appendix 2 or Appendix which is characterized in that by introducing directly from the gas inlet port provided on the spin coater cup 1 4. The spin coating method according to 3.
(Supplementary note 5) The spin coating method according to any one of supplementary notes 1 to 4, wherein the spin coating material 3 is a spin coating material 3 that forms a film by advancing a chemical reaction during spin coating.
(Supplementary Note 6) material to be introduced in a gaseous state to the spin coater cup 1, the spin coating method according to Note 5, wherein the spin-coating material 3 is characterized in that it is a substance which produces when polymerized.
(Supplementary Note 7) material to be introduced in a gaseous state to the spin coater cup 1, the spin coating method according to Note 5 spin coating material 3 is characterized in that the material to be consumed for polymerization.
(Supplementary Note 8) Examples spin coating material 3, the spin coating method according to any one of Supplementary Notes 1 to Appendix 7, characterized in that a material for the alkoxysilane raw material.
(Supplementary note 9) The spin coating method according to any one of supplementary notes 1 to 8, wherein water is used as the material to be introduced in the gas phase state .
(Supplementary note 10) The spin coating method according to any one of supplementary notes 1 to 8, wherein alcohol is used as the material to be introduced in the gas phase state .
( Supplementary note 11) The spin coating method according to any one of supplementary notes 1 to 8, wherein ozone is used as the material to be introduced in the gas phase state.
(Additional remark 12 ) The low dielectric constant interlayer insulation film is formed using the spin coat method of any one of Additional remarks 1 thru / or appendix 11 , The manufacturing method of the low dielectric constant interlayer insulation film characterized by the above-mentioned.
(Additional remark 13 ) The manufacturing method of the semiconductor device characterized by forming a low-dielectric-constant interlayer insulation film using the spin coat method of any one of Additional remark 1 thru | or Additional remark 11 , and forming a multilayer wiring structure.

  As a practical example of the present invention, a film formation process of a low dielectric constant oxide film is typical, but it is also applied to a film formation process of another inorganic insulating film such as a SiN film, It can also be applied to the photoresist coating process, and in any case, it can be applied when the physical properties of the film formed can be changed by controlling the film forming atmosphere. It is.

It is explanatory drawing of the fundamental structure of this invention. It is a notional block diagram of the spin coater used for the spin coat method of Example 1 of the present invention. It is a notional block diagram of the spin coater used for the spin coat method of Example 2 of the present invention. It is a reaction control gas introduction flow figure in Example 2 of the present invention. It is a notional block diagram of the spin coater used for the spin coat method of Example 3 of this invention. It is a reaction control gas introduction flow figure in Example 3 of the present invention. It is a notional block diagram of the spin coater used for the spin coat method of Example 4 of this invention. It is explanatory drawing of the formation method of the multilayer wiring structure of Example 5 using the spin coat method of this invention. It is explanatory drawing of the formation method of the multilayer wiring structure of Example 6 using the spin coat method of this invention. It is explanatory drawing of the formation method of the multilayer wiring structure of Example 7 using the spin coat method of this invention. It is a notional block diagram of the conventional general spin coater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spin coater cup 2 Substrate 3 Spin coating material 4 Vapor phase material 11 Chamber 12 Atmosphere supply pipe 13 Reaction control gas introduction pipe 14 Exhaust pipe 15 Filter 16 Spindle motor 17 Wafer chuck 18 Wafer 19 Spin coater cup 20 Exhaust port 21 Drain pipe 22 Spin Coating material supply nozzle 23 Humidity adjustment port 24 Ethanol concentration adjustment port 25 Ozone concentration adjustment port 26 Reaction control gas introduction tube 31 Base insulating film 32 First interlayer insulating film 33 First embedded Cu wiring layer 34 Via forming insulating film 35 Via 36 Second interlayer insulating film 37 Second embedded Cu wiring layer 38 CMP resistant layer 39 Hydrophilic layer 40 Third interlayer insulating film 41 Via 51 Chamber 52 Atmosphere supply pipe 53 Exhaust pipe 54 Filter 55 Spindle motor 56 Wafer chuck 57 Wafer 58 Spin coater Cup 59 Exhaust port 60 Liquid pipe 61 spin coating material supply nozzle

Claims (6)

A spin coating method comprising introducing a material that reacts with a spin coating material into a spin coater cup in a gas phase during spin coating. The material to be introduced in a gaseous state into the spin coater within cup, spin coating method according to claim 1, wherein the spin-coating material is characterized in that it is a substance which produces when polymerized. The material to be introduced in a gaseous state into the spin coater within cup, spin coating method according to claim 1, wherein the spin-coating material is characterized in that the material to be consumed for polymerization. 2. The spin coating method according to claim 1, wherein the material introduced into the spin coater cup in a gas phase is either alcohol or ozone, and the spin coating material is alkoxysilane. A method for producing a low dielectric constant interlayer insulating film, comprising: forming a low dielectric constant interlayer insulating film by using the spin coating method according to claim 1 . 5. A method of manufacturing a semiconductor device, comprising: forming a multilayer wiring structure by forming a low dielectric constant interlayer insulating film by using the spin coating method according to claim 1 .

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