JP2001168076A5 - - Google Patents

Description

[0007]
As described above, it is extremely effective to perform the cleaning process using H ₂ O, H ₂ O ₂ or the like from the viewpoint of waste liquid treatment. However, on the other hand, a huge amount of power is required to produce pure water. Therefore, a significant reduction in the amount of pure water used in the cleaning process is desired. That is, the development of a dry cleaning technology that is an alternative to the conventional liquid phase cleaning technology is eagerly desired.

[0029]
In order for the first molecule to be in a more reactive state, the second molecule in an optimal state is required. Energy may be provided to the cluster from outside the system to achieve this optimum. The external energy given at this time varies depending on the number of molecules constituting the cluster, ie, the structure of the cluster. The optimum cluster structure differs depending on the type of the first and second molecules, but merely acting as a uniform dielectric in the liquid phase does not have the effect of reducing the activation energy of the reaction. That is, in order to make the first molecule in a highly reactive state with a low activation energy, the liquid phase consisting of the first and second molecules is a usual mixture of the first and second molecules. It is necessary to form a cluster consisting of the first and second molecules and to utilize the internal energy generated as a result of the formation of the cluster, not in the gas phase.

[0046]
Following reaction formula:
H ₂ O ₂ n H ₂ O → H ₂ OO · n H ₂ O (n is an integer of 0 to 3)
H ₂ O ₂ → ₂ OH
Single reaction configuration using the basis function aug-cc-pVDZ that is optimized for post Hartree-Fock calculations mainly for energy changes (reaction potential surface: PES) across all reaction pathways of chemical reactions shown in It calculated by Mphiller-Plesset second-order perturbation method (MP2) and density functional theory (BHandHLYP) which make Hartree-Fock a reference arrangement.

[0050]
In particular Remarkably, when Involve of H _{2 O} 2 molecules, barrier H ₂ OO formation reaction H ₂ O were measured relative to the state of H ₂ O ₂ adsorbed, intramolecular hydrogen In both the transfer process and the intermolecular hydrogen transfer process, it is only about 4 kcal / mol lower than in the case where one molecule of H ₂ O is involved, but each of H ₂ O and H ₂ O _{2 in} the dissociation limit It was found that the heat absorption required for the H ₂ OO formation reaction measured on the basis of the state was significantly reduced. Therefore, the same tendency is obtained when the same examination is carried out also in the case where three molecules of H ₂ O are involved, and it is known that the heat absorption from the dissociation limit becomes almost zero.

[0055]
On the other hand, for example, as shown in FIG. 5, with regard to three pathways in which two molecules of H ₂ O form a dimer and are adsorbed to the H ₂ O ₂ molecule, one of H ₂ O is H as a proton acceptor. The H of ₂ O ₂ and the other H ₂ O form a hydrogen bond with O of H ₂ O ₂ as a proton donor. The barriers are (intramolecular hydrogen transfer, intermolecular hydrogen transfer) in the order of path1 (45.32, 33.13), path2 (45.58, 33.64), path3 (46.39, 34.69) kcal, respectively. It was / mol.

[0056]
From the above, in a system in which two molecules of H ₂ O are involved, when they form a dimer and are adsorbed to H ₂ O ₂ , hydrogen between two H ₂ O molecules is compared with the case where they are adsorbed as a monomer Although the adsorption state is stabilized by the binding component, the 1,2-hydrogen shift transition state is further stabilized, so that the barrier of the intramolecular hydrogen transfer process is reduced by about 4 kcal / mol. This reduction strengthens the interaction between the H atom of the positively polarized H ₂ O molecule and the O atom of the more negatively polarized H ₂ O ₂ molecule in the intramolecular hydrogen transfer process by forming a dimer. In other words, the energy loss required for the internal strain of the H ₂ O ₂ molecule is mitigated by the H ₂ O molecule as the catalyst (a shift of LUMO, HOMO, 2nd HOMO).

[0058]
The point to be particularly noted in the results of H _{2 O} molecule described above can of H _{2 O} system, as well as two molecules involved was obtained with respect to the system involved, in a system of H _{2 O} 2 molecules are involved, monomers path The heat absorption required to generate oxywater based on the dissociation limit is significantly reduced compared to a system involving one molecule of H ₂ O, regardless of whether it is a dimer pathway or a dimer pathway It is. This tendency is more pronounced especially in intermolecular hydrogen transfer pathways. The above results show that the heat of adsorption generated when H ₂ O molecules are adsorbed to H ₂ O ₂ molecules is not dissipated but stored as internal energy, ie, in the gas phase process (dry process) It shows that this heat absorption amount can be effectively used for the above-mentioned heat absorption amount (external work).

[0060]
On the other hand, if the first and second H ₂ O molecules are interacting with the H ₂ O ₂ molecules in the monomer pathway, then the H ₂ O ₂ molecules use up their proton donating sites, so the third H ₂ O ₂ The structure in which the O molecule interacts independently with the H ₂ O ₂ molecule is disadvantageous. Therefore, the third H ₂ O molecule has to interact with the first and second H ₂ O molecules. That is, one of the first and second H _{2 O} molecules becomes possible to form the third H _{2 O} molecules and dimeric structures, finally reaction path and dimers route described above is equal.

[0064]
(3) In a system in which three molecules of H ₂ O are involved, the 1,4-hydrogen shift barrier from adsorption is about 28 kcal / mol, but the 1,4-hydrogen shift barrier based on the dissociation limit is almost It will be zero.

【表５】

ｇｅｏｍｅｔｒｙの変化から、反作用場（双極子場）の有無による２％程度以下であるが、分極の大きな構造（遷移状態、生成系）ほど変化は大きいことが分かった。[0071]
Figure 7 is a graph showing the relationship between the path and the energy generated in the liquid phase H ₂ OO from H 2 _O. Moreover, energy change amount is shown in Table 4 and Table 5. Incidentally, in FIGS. 8 and 9 show a structural change in the molecules H ₂ O ₂ due to the reaction shown in FIG. 7, 8 molecules H ₂ O ₂ due to the reaction of H _{2 O} molecules is not involved structure shows the change, FIG. 9 shows the structural changes of the molecules H ₂ O ₂ due to reaction of H _{2 O} molecule is involved. The lines surrounding the structures in FIG. 8 and FIG. 9 indicate spherical holes of radius a ₀ described in the calculation method in the Onsager method, and equal charge surfaces of 0.0004 au in the SCIPCM method.
[Table 4]

[Table 5]

From the change of geometry, it is found that the change is larger as the structure of the polarization (transition state, generation system) is about 2% or less due to the presence or absence of the reaction field (dipolar field).

[0072]
First, look for self-decomposition reaction of _H 2 _{O 2} not involved in _{H 2} O. The autolysis reaction of H ₂ O ₂ in the gas phase (ε = 1) is a highly endothermic reaction with a very high barrier, both in the pathway to generate OH radicals and the pathway to generate H ₂ OO (→ O atom), Progress requires photodissociation and metal catalysts. This tendency did not change even considering the reaction field. The reaction barriers decrease by only 1 kcal / mol in the Onsager field and as low as 2 kcal / mol in the SCIPCM field. The absolute value of Mulliken's charge on each atom increases in the order of gas phase → Onsager field → SCICPM field. Therefore, the electric dipole moment as a molecule also increases, but the change from the primordial system to the transition state is almost constant. Therefore, the difference in reaction field corresponding to the difference in induced electric dipole moment is reduced.

[0073]
Finally, although the PES from the primordial system to the transition state is about the same, the PES from the transition state to the generation system (H ₂ OO) is quite different, and the stabilization energy (in other words, the barrier to reverse reaction) is about 5 to 5 It is increased by 8 kcal / mol. The change of Mulliken's charge in the gas phase and the SCRF method is also larger than that of the primordial system and the transition state. Although H ₂ OO itself is originally highly polarized, the excess O atom of the negative charge exhibits strong oxidizing properties, but this large polarization is further enhanced by the reaction field.

[0077]
In the transition state, those electric dipole moment of the big _{H 2} O ₂ by about 20% than the _{H 2 O} 2 is, receive stronger reaction field of "ε = 78.3 water". Therefore, the intramolecular hydrogen transfer process hydrogen bond formation between the O atom and of H _{2 O} H atoms of H ₂ O ₂ is suppressed. This weakens the effect of promoting the negative polarization of the O atom that should exhibit oxidative properties. Also in intermolecular hydrogen transfer process, in the course of the transition state from the suction state, although O atoms H 2 _O is effectively acts on H withdrawal from H ₂ O ₂ as a proton acceptor, to H ₂ O ₂ The promotion effect of H donation is small.

[0082]
In the case of a gas phase reaction system, as the number of catalyst H ₂ O molecules increases to 0, 1, 2, 3, the Mu11iken charge of the O atom exhibiting this oxidizing property is −0.5052 (0 molecule H ₂ O) , -0.5394 (one molecule), -0.5662 to -0.5902 (two molecules), -0.5981 to -0.6180 (three molecules) (MP2 / aug-cc-pVDZ) Value at the level). In the SCRF method used this time, although the charge distribution can not reproduce the measured value yet, the effect of the reaction field may be considered to be almost saturated at ε = 78.3. That is, even if a large number of H ₂ O molecules promote the polarization of H ₂ OO as a liquid phase (eg, the average sum of electric dipoles oriented in various directions), the effect is almost as high as the amount of polarization shown above It is thought that it will be saturated.

[0085]
From this, the catalytic effect of H ₂ O, that is, the apparent reaction barrier lowering effect and the oxidizing property enhancing effect are
(3) Not due to the dielectric properties that H ₂ O exerts on the reaction system as a group (4) Represented by the gas phase reaction system realized for the first time by the concerted reaction of H ₂ O ₂ and H ₂ O It turned out to be a feature of the direct reaction between molecules.

[0086]
This is because the number of water molecules (eg, liquid phase, solid phase) that cause dielectric property is not necessary in promoting the oxidation species generation reaction in H ₂ O + nH ₂ O system and controlling the oxidation property. Indicates that it can contribute to the reduction of the amount of pure water used.

[0087]
However, in order to effectively use the apparent barrier reduction, it is necessary to store the H ₂ O adsorption energy to the H ₂ O ₂ molecule as internal energy and not dissipate it, that is, to suppress the collisional relaxation of reaction products. As important, it is difficult to perform such control in the liquid phase. Therefore, it can be said that the production of oxywater is effective in a gas phase reaction system. Instead, with regard to decontamination, it is necessary to consider steps equivalent to metal ion removal by hydration, which is an advantage of liquid phase reaction systems, and electrostatic removal of particles by zeta potential control.

[0090]
From these results, in order to generate oxidized species with high efficiency in a system of hydrogen peroxide and water, it is preferable to satisfy the following requirements. That is, three molecules of water act on one molecule of hydrogen peroxide. Further, instead of reacting hydrogen peroxide and water in the bulk of the liquid phase and the gas phase, for example, they are separately supplied near the surface of the object to be reacted. Alternatively, these clusters are generated in a gas phase bulk whose density is three or more orders of magnitude smaller than that of the liquid phase, and the internal energy stored as the clusters are generated is suppressed on the surface of the object while suppressing dissipation by collision relaxation. Supply to generate oxidized species on the surface of the object. Alternatively, H ₂ O trimers, H ₂ O dimers, H ₂ O monomers, H ₂ O ₂ dimers, and H ₂ O can be used to supply hydrogen peroxide and water to the surface of the object while suppressing their clustering. A microwave of 3 GHz or more capable of rotational excitation of O ₂ monomer is applied. By adopting at least one of these, it is possible to generate oxidized species with higher efficiency.

[0134]
Further, as described above, in order to suppress the heat of adsorption generated by the adsorption of water to hydrogen peroxide from being dissipated due to the collision of gas molecules, the total pressure in the processing chamber 3 is low and the exhaust speed is low. Fastness, that is, short residence time of the process gas in the processing chamber 3 is of primary importance. Secondly, it is also important that the vibration degree of freedom 3N-6 (N is the number of constituent atoms of gas molecules) of the gas used for dilution supply is small, or the molecular weight of the gas used for dilution supply is large. The most preferable gas is a heavy rare gas (Kr or Xe) having zero vibrational freedom, but diatomic molecules such as nitrogen and oxygen having one vibrational freedom are also preferable. Alcohols such as isopropyl alcohol can be used as a gas used for dilution and supply because the drying on the substrate 11 is sufficiently fast, but in the case of isopropyl alcohol, the vibration freedom is 30. It is usable if the vibration degree of freedom is 60 or less including the isopropyl alcohol dimer.

[0167]
Further, the defect density measured by the electron spin resonance method is 3 × 10 ¹⁶ / cm ^{3 at the} E ′ center and 1 × 10 ¹⁶ / cm ³ at the defects attributed to the peroxide radical and the non-crosslinked hole center. It has been found that it is less than the conventional plasma CVD oxide film. If a gas containing fluorine, such as SiF ₄ gas, is not introduced, a normal silicon oxide film can be formed. In addition, TEOS (Si (OC ₂ H ₅ ) ₄ ) or its fluorinated gas (SiF _n , (OC ₂ H ₅ ) _4-n , n = 1 to 3) used for forming a fluorine-added silicon oxide film or silicon oxide film ), Fluorosilane gas SiF _n H _4-n , (n = 1 to 3) or the like may be used.

Brief Description of the Drawings
FIG. 1 is a graph showing the relationship between energy and a pathway for generating H ₂ OO from H ₂ O ₂ in the gas phase.
FIG. 2 is a diagram showing a structural change of H ₂ O ₂ molecules when a reaction of generating H ₂ OO from H ₂ O ₂ without H ₂ O molecules is generated in a gas phase.
Figure 3 illustrates one molecule of _{H 2} O molecules _H 2 OO is generated from _H 2 _{O 2} involved the reaction is a structural change in the molecules _H 2 _{O 2} when occurring in the gas phase.
4 is a diagram showing a structural change in the molecules _H 2 _{O 2} when occurring _{H 2} O monomer 2 molecules to generate involvement to _H 2 _{O 2} from _H 2 OO reactions in the gas phase.
[5] structural changes in the molecules _H 2 _{O 2} when occurring _{H 2} O dimer generated from _{H 2} O molecules of 2 molecules involved _H 2 _{O 2} from _H 2 OO is produced reaction in the gas phase Figure showing.
FIG. 6 is a diagram showing a structural change of H ₂ O ₂ molecules when a reaction in which H ₂ O is generated from H ₂ O ₂ by involving 3 molecules of H ₂ O molecules occurs in the gas phase.
FIG. 7 is a graph showing the relationship between energy and a pathway for producing H ₂ OO from H ₂ O ₂ in a liquid phase.
8 shows _{H 2} O molecules generated by _H 2 OO from _H 2 _{O 2} without involving reaction of structural changes in the molecules _H 2 _{O 2} when occurring in the liquid phase.
9 is a diagram showing one molecule of _{H 2} O molecules involved in _H 2 _{O 2} from _H 2 OO generates reaction structural changes in molecules _H 2 _{O 2} when occurring in the liquid phase.
FIG. 10 schematically shows a surface treatment method according to an embodiment of the present invention.
FIG. 11 schematically shows a surface treatment method according to an embodiment of the present invention.
FIG. 12 schematically shows a surface treatment system according to an embodiment of the present invention.
[Description of the code]
DESCRIPTION OF SYMBOLS 1 ... Semiconductor processing apparatus; 2 ... Storage container; 3 ... Processing chamber 4 ... Load lock chamber; 5, 6 ... Gate valve; 7 ... Connection means 8 ... Door; 9 ... Processing container; 10 ... Mounting base; 11 ... Substrate 12 ... Shower head; 13: Gas supply means 14, 20, 23, 28, 31: Valves 15, 22, 30: Exhaust ports 16, 24: Exhaust means 17: Conveying means 18: Driving means 19: Gas supply means 21 29 Filter 26 25 cassette 26 holding means 27 32 opening 35 organic substance 36 metal contamination 37 particle

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