JP2000183018A - Cleaning method and device of semiconductor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to set the most suitable chemical conditions for the physical properties of a work, by a method wherein a variable related to chemicals is controlled on the basis of a formula so as to enable the amount of a metal oxide film to be dissolved to amount to a prescribed value when a semiconductor substrate is cleaned. SOLUTION: The pH of chemicals is the most important when chemical conditions are set. The allowable amount of a metal oxide film dissolved to cause no deterioration in the characteristics of the metal oxide film is previously determined, and the pH conditions are calculated by the use of a dissolution volume calculation formula. A method of determining the amount of chemicals to replenish is obtained through a manner where a formula which represents an excess or a shortage of chemicals by the use of one or more variables related to chemicals is obtained, and when a cleaning operation is carried out, the variables are controlled one the basis of the formula to enable the dissolution amount or degree of damage of a metal oxide film so as not to exceed a prescribed value. Data used for the above setting are stored in a data processor, and the setting is carried out. By this setup, the most suitable chemical conditions for a work are set, maintained, and controlled, so that a cleaning operation can be effectively carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for cleaning a metal oxide film.

[0002]

2. Description of the Related Art In recent years, research on a method for producing a highly functional oxide and its application has been actively conducted due to industrial requirements.
For example, in the field of semiconductors such as catalysts, magnetic materials, and pigments, methods of using ferroelectric oxides as capacitance insulating films instead of conventional silicon oxides have been widely studied. The physical properties of these highly functional oxides are precisely controlled by their composition, structure, surface state, particle size, film thickness, etc., and their characteristics change due to slight effects of impurity adhesion and changes in state. It has been known. In particular, a very high degree of cleanliness is required for a ferroelectric film whose film thickness and composition are controlled at the nano level. In order to maximize the properties of such a material having a high function, it is necessary to develop a high-precision cleaning technique for obtaining high cleanliness. Hereinafter, a conventional method for cleaning a ferroelectric film will be described with reference to the drawings.

FIGS. 11 (a) to 11 (d) show Japanese Unexamined Patent Publication No.
It is a process sectional view showing the manufacturing method of the capacity element using the ferroelectric oxide indicated in 2828 gazette. First,
As shown in FIG. 11A, a capacitor element electrode or a capacitor insulating film 35 is formed on a wafer 34 by a sputtering method or an organic metal deposition method, and then a mask 36 for processing into a desired shape is formed. You. Next, as shown in FIG. 11B, the capacitor element electrode or the capacitor insulating film 35 is dry-etched. At this time, the etching residue 37 adheres to the side wall of the mask 36, but as shown in FIG.
The reaction product 37 is washed with a chemical under a nitrogen atmosphere without exposing the substrate to the atmosphere. In this case, the chemical
It is a mixture of hydrochloric acid and water or a mixture of hydrofluoric acid and nitric acid. Finally, as shown in FIG. 11D, the mask 36 is removed.

[0004]

However, the method disclosed in Japanese Patent Application Laid-Open No. Hei 10-12836 not only dissolves and removes reaction products attached on the ferroelectric film, but also removes the ferroelectric film. There was a problem that it also dissolved itself.

[0005] The characteristics of ferroelectric films such as PZT, BST, and SBT greatly change due to slight changes in composition, surface condition, and the like. Therefore, if the components constituting the ferroelectric film are dissolved by washing or the surface of the ferroelectric film is altered, its characteristics may be significantly deteriorated. Therefore, in order to perform cleaning without deteriorating the characteristics of the ferroelectric film, it is necessary to perform cleaning under optimal chemical solution conditions according to the properties of the object to be cleaned.

As described above, in cleaning the substrate provided with the ferroelectric film, the quality deterioration of the ferroelectric film must be minimized. Strict chemical liquid management is required from a viewpoint different from the cleaning of the semiconductor substrate.

Further, in cleaning after patterning the ferroelectric film by dry etching, a more strict level of chemical liquid management is required. When the ferroelectric film is patterned by dry etching, an etching residue mainly composed of a reaction product between the ferroelectric film material and an etching gas adheres to the ferroelectric film. Conventionally, the removal of the etching residue has been performed using a mixed solution of hydrochloric acid and water or a mixed solution of hydrofluoric acid and nitric acid. However, this has a problem that the ferroelectric film itself is also dissolved. This is because a cleaning solution that can dissolve etching residues containing a compound of a ferroelectric film material as a main component also has strong solubility in a ferroelectric film. Therefore, it is desirable that the cleaning of the ferroelectric film is based on the action that does not involve the dissolution of the etching residue. In addition, since it is necessary to minimize dissolution of the ferroelectric film as described above, it is desirable to perform cleaning by an operation without lift-off. As such a cleaning method, for example, cleaning based on an action by electrostatic repulsion can be considered. In other words, the cleaning is based on the effect of effectively reducing the adhesion of the etching residue to the ferroelectric film and the like and the adhesion between the etching residues. However, it is generally difficult to accurately determine the chemical conditions under which such an action occurs. This is because the conditions under which the above-described effects are exhibited differ depending on the type of the chemical solution, the object to be cleaned, and the like, and the range satisfying such conditions is often very narrow. Therefore, in order to realize the cleaning based on the above-described action, it is essential to strictly manage the chemical based on the reaction analysis between the chemical and the object to be cleaned.

[0008] In cleaning a substrate on which a silicon oxide film or the like is formed instead of a ferroelectric film, a higher level of cleanability than in the past has been required in recent years. Chemical liquid control has been required.
However, in the conventional cleaning method, a method of controlling the chemical solution by maintaining the concentration and temperature of the chemical solution at a specific value has become mainstream, and strict chemical solution management based on a reaction analysis between the chemical solution and the object to be cleaned is performed. The cleaning method to be performed has not been found. Several techniques for controlling the surface treatment of a substrate using mathematical formulas have been proposed.
JP-A-332-332 discloses a method of creating a characteristic line having a relational expression between a dissolution amount of a silicon substrate and an etching rate and automatically controlling an etching processing time using the characteristic line. This is because the chemical solution becomes fatigued as the dissolution of the substrate progresses,
In order to solve the problem that the etching rate is lowered, an etching rate reduction width is predicted using an empirical formula created in advance. However, the technology described in the above publication relates to wet etching of a substrate, and is not intended for cleaning a substrate, and a variable relating to a chemical is not taken into a mathematical expression, thereby realizing advanced control of a chemical. Not something.

In view of the above circumstances, the present invention sets the optimum chemical solution condition according to the physical properties of the object to be processed by using a predetermined mathematical formula in cleaning the substrate provided with the oxide film.
Provided are a semiconductor substrate cleaning method and a cleaning apparatus capable of strictly managing a chemical solution under the set conditions even during cleaning and performing effective cleaning without deteriorating characteristics of an object to be cleaned. It is an object.

[0010]

According to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof using a chemical solution. The amount by which the metal oxide film dissolves due to a chemical reaction between the film and the chemical solution is calculated using one or two or more variables related to the chemical solution, and the metal oxide film dissolves during cleaning. A method for cleaning a semiconductor substrate is provided, wherein the variable is controlled based on the mathematical expression so that the amount falls within a predetermined range.

As described above, when a semiconductor substrate provided with a metal oxide film is cleaned using a chemical solution, the oxide film may be dissolved in the chemical solution and its characteristics may be deteriorated. To solve such a problem, the present invention solves the problem by obtaining, by experiment or reaction analysis, a mathematical expression expressing the amount of the oxide film dissolved in the chemical solution using variables related to the chemical solution, and using this to control the chemical solution. Is being planned. That is, in the present invention, the dissolved amount of the oxide film is formulated as a function using the concentration, pH value, and the like of a predetermined component of the chemical solution as variables, and setting of the chemical solution conditions and control of the chemical solution replenishment amount,
In controlling the chemical solution conditions, the variable is controlled so that the dissolved amount of the oxide film falls within a predetermined range.

Further, according to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, the method comprising the steps of: Obtain a mathematical expression expressing the degree of damage to the metal oxide film by the reaction using one or more variables related to the chemical solution, and during cleaning, such that the degree of damage to the metal oxide film falls within a predetermined range. A method for cleaning a semiconductor substrate is provided, wherein the variable is controlled based on the equation.

When a semiconductor substrate provided with a metal oxide film is cleaned using a chemical solution, the oxide film may be damaged by the chemical solution, and its characteristics may be deteriorated. To solve such a problem, the present invention solves the problem by obtaining, by experiment or reaction analysis, a mathematical expression expressing the amount of the oxide film dissolved in the chemical solution using variables related to the chemical solution, and using this to control the chemical solution. Is being planned. That is, in the present invention, the degree of damage to the oxide film is formulated as a function using the concentration of a predetermined component of the chemical solution, the pH value, or the like as a variable, and the setting of the chemical solution condition, the control of the chemical solution replenishment amount, and the management of the chemical solution condition By controlling the variables, the degree of damage to the oxide film falls within a predetermined range. Here, the degree of damage to the oxide film refers to the degree of roughness (irregularities) and alteration of the oxide film surface.

Further, according to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, the method comprising the step of cleaning a semiconductor substrate between the metal oxide film and the chemical solution. Cleaning of a semiconductor substrate, characterized in that a temporal change in the composition of the chemical solution due to a reaction is obtained by using a mathematical expression expressing one or more variables related to the chemical solution, and the chemical solution is replenished based on the mathematical expression. A method is provided.

Further, according to the present invention, there is provided a semiconductor substrate cleaning method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, wherein one or more variables related to the chemical solution at time t ₁ are provided. The method for cleaning a semiconductor substrate is characterized in that a formula expressing the composition of the chemical solution at time t ₂ (t ₂ > t ₁ ) is obtained by using the formula, and the chemical solution is replenished based on the mathematical formula. .

When a semiconductor substrate is cleaned for a certain period of time using a chemical solution, the chemical solution is fatigued by the cleaning. The chemical solution fatigue means that the cleaning components in the chemical solution decrease or the impurity concentration increases. The impurities include a chemical solution and a metal or semiconductor oxide film, a reaction product generated by a reaction between the semiconductor substrate material and the chemical solution, and the like. When the fatigue of the drug solution becomes remarkable,
Cleaning is not performed effectively. In addition, a long cleaning time must be taken in order to obtain a certain degree of cleaning, which causes a problem that the dissolution and damage of the metal oxide film increase. Therefore, in the present invention, the change over time of the chemical solution composition is formulated as a function using the initial concentration of a predetermined component of the chemical solution as a variable,
At the time of replenishing the chemical, the variable is controlled so that the chemical composition falls within an appropriate range. As a result, the chemical solution can be replenished while maintaining the cleaning ability of the chemical solution well and keeping the dissolution and damage degree of the oxide film within a predetermined range.

Further, according to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof using a chemical solution, the method comprising the step of cleaning a semiconductor substrate between the metal oxide film and the chemical solution. A semiconductor, wherein a reaction is obtained by calculating a mathematical expression using one or more variables related to the chemical solution, and at the time of cleaning, controlling the progress of the chemical reaction by controlling the variable based on the mathematical formula. A method for cleaning a substrate is provided.

"Chemical reaction occurring between the metal oxide film and the chemical solution" refers to a chemical reaction representing the dissolution or alteration of the oxide film by the chemical solution. In the present invention, the chemical reaction is expressed as a reaction rate equation, a chemical equilibrium equation, or the like using variables related to the chemical solution. That is, the reaction rate or the like is formulated as a function using the concentration of a predetermined component of the chemical solution or the like as a variable. It controls the progress of the chemical reaction.

Further, according to the present invention, there is provided a semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate provided with a metal oxide film on a surface by using a chemical, wherein (A) a concentration of a predetermined component contained in the chemical or a chemical. Measuring means for intermittently or continuously measuring the concentration, activity or physical quantity related to the activity of the chemical species contained in (A), and (B) a mathematical formula for controlling the properties of the chemical solution and predetermined data related to the chemical solution. Data storage means for storing; and (C) arithmetic means for calculating an optimum chemical solution condition based on the measured value obtained by the measurement means and the mathematical formula and the predetermined data stored in the data storage means. And (D) a chemical liquid replenishing means for replenishing a predetermined component of the chemical liquid so as to perform the cleaning under the optimum chemical liquid condition.

This cleaning device is provided with data storage means for storing mathematical formulas and the like for controlling the properties of the chemical solution, and based on the mathematical formulas and the like, under the optimal chemical solution conditions, that is, the conditions under which the desired cleaning efficiency can be obtained. Replenishment of a predetermined component of the chemical solution is performed so that cleaning is performed. Therefore, the above-described method for cleaning a semiconductor substrate of the present invention can be suitably realized,
Efficient cleaning can be performed while avoiding dissolution or damage of the metal oxide film or fatigue of the chemical solution.

Here, the mathematical expression for controlling the properties of the chemical solution refers to an expression representing the amount of dissolution and damage of the metal oxide film, the temporal change of the composition of the chemical solution, and the like, and the concentration or the concentration of a predetermined component contained in the chemical solution. It refers to a substance containing the concentration, activity or physical quantity related to the activity of a chemical species contained in a chemical solution as a variable. Also,
“Replenishment of a predetermined component of the chemical” includes not only the replenishment of the chemical during the cleaning but also the initial preparation of the chemical.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for cleaning a semiconductor substrate having a surface provided with a metal oxide film. The metal oxide film refers to a silicon oxide film, a ferroelectric film, or the like.
In the cleaning of a substrate provided with these films, strict control of chemicals based on reaction analysis is required. In particular, in cleaning a semiconductor substrate provided with a ferroelectric film, it is necessary to prevent the ferroelectric film from being dissolved or deteriorated, and thus more strict management of a chemical solution is essential.

In the present invention, the type of the semiconductor substrate is not particularly limited.
A substrate or the like made of a group V semiconductor material can also be used.

According to the present invention, a variable relating to a chemical solution is controlled using a predetermined mathematical formula, whereby the amount of metal oxide film dissolved, the degree of damage, the change over time in the chemical solution composition, or the progress of a chemical reaction are kept within a certain range. To control. The variable relating to the chemical refers to a variable representing the property of the chemical, etc., and refers to a predetermined variable relating to the chemical, such as the composition or temperature of the chemical, the concentration of a predetermined component included in the chemical, or the chemical species included in the chemical. Concentration, activity or physical quantity related to activity, pH of drug solution
And the like. The predetermined mathematical expression can be obtained by experiment or chemical analysis. When the object to be cleaned includes a ferroelectric film, it is preferable to use pH or the like as a variable.

The ferroelectric film of the present invention is used, for example, as a capacitive insulating film of a capacitive element. What is ferroelectric?
A material that has spontaneous polarization and has the property that it can be inverted by an electric field. Typically, a metal oxide having a perovskite structure can be given.

The ferroelectric film in the present invention is, for example, a metal oxide film having a relative dielectric constant of 10 or more. Among them, an oxide containing at least one selected from strontium, titanium, barium, zirconium, lead, bismuth, and tantalum is preferable. Specifically, BST (Ba
_x Sr _1-x TiO ₃ ), PZT (PbZr _x Ti _1-x O ₃ ),
_{PLZT (Pb 1-y La y} Zr x Ti 1-x O 3), SrBi 2
It is preferable that the film is a film made of a perovskite-based material such as Ta ₂ O ₉ .
0 ≦ x ≦ 1 and 0 <y <1. ). Alternatively, Ta ₂ O ₅ or the like can be used. When such a material is selected, the effects of the present invention are more remarkably exhibited. That is,
When these materials are applied to a capacitor, a large storage capacitance can be obtained, but there is a problem that it is difficult to remove an etching residue while suppressing a film loss and a characteristic deterioration of a ferroelectric film. . According to the method of the present invention, since such a problem is solved, the excellent characteristics of the above-mentioned material can be fully utilized.

In the present invention, the method for forming the ferroelectric film is not particularly limited. For example, in the case of a PZT film, it can be formed by a known method such as a sol-gel method, a sputtering method, and a CVD method.

The cleaning method of the present invention exhibits a remarkable effect when a substrate having a ferroelectric film is to be cleaned, and in particular, a substrate having a ferroelectric film patterned by dry etching is to be cleaned. In this case, a more remarkable effect is exhibited. When a substrate provided with a ferroelectric film is to be cleaned, it is preferable to use an alkaline cleaning liquid as a chemical. The etching residue adhering to the ferroelectric film is effectively removed by washing with an alkaline washing solution. However, the cleaning using the alkaline cleaning liquid is not a cleaning action due to the dissolution or lift-off effect of the etching residue, but mainly a cleaning that effectively reduces the adhesion of the etching residue to the ferroelectric film and the like and the adhesion between the etching residues. Cleaning is performed by the action. Cleaning based on such an action requires more strict management of the chemical solution, and the effect of the present invention of controlling the chemical solution based on the analysis of the reaction between the chemical solution and the object to be cleaned is more remarkably exhibited.

The alkaline cleaning solution in the present invention may be any alkaline solution, but is preferably 8 or more, more preferably 9 or more, so that the etching residue can be more effectively prevented while preventing the ferroelectric film from being thinned. Can be removed. Further, by setting the pH to 13 or less, more preferably 12 or less, dissolution and surface roughness of the surface of the silicon oxide film formed on the semiconductor substrate can be suppressed.

The alkaline cleaning solution of the present invention preferably has a redox potential lower than the redox potential of the components of the ferroelectric film, and more preferably has a negative redox potential. A ferroelectric film having an oxidation-reduction potential higher than the oxidation-reduction potential of a composition component has a function of oxidizing an incompletely oxidized composition component existing near the surface of the ferroelectric film. In some cases, the surface of the body film may be deteriorated and its characteristics may be deteriorated. For example, APM
The oxidation-reduction potential of (ammonia-hydrogen peroxide solution) is a positive value and is higher than the oxidation-reduction potential of a metal oxide used as a ferroelectric film. For this reason, the surface of the ferroelectric film may be deteriorated and its characteristics may be impaired.

For the same reason as described above, it is preferable that the alkaline cleaning solution in the present invention does not contain an oxidizing agent or a reducing agent. In particular, when hydrogen peroxide, which can act as both an oxidizing agent and a reducing agent, is used in combination with the ferroelectric film, the hydrogen peroxide reacts with the ferroelectric film to cause self-decomposition and is included in the ferroelectric film. It is preferable to avoid using a specific element (for example, Ti or the like) in combination to form a complex with the specific element (for example, Ti or the like) and cause a surface composition deviation.

As the alkaline cleaning solution in the present invention,
For example, a cleaning solution containing aqueous ammonia, amines, ammonium salts, and the like is used. Whichever one of them is selected, an electrostatic repulsion action due to being alkaline can be obtained, and an etching residue can be removed. However, more advantages can be obtained by selecting particular ones of the above. For example, it is preferable to contain one or more components selected from the group consisting of ammonia, tetramethylammonium hydroxide (TMAH), and trimethyl (2-hydroxy) ethylammonium hydroxide. By using a cleaning solution containing such components, it is possible to more effectively remove etching residues while preventing the ferroelectric film from being reduced in thickness. Further, there is little residual cleaning liquid, and the cleaning liquid is less likely to be adsorbed on the ferroelectric film and adversely affect the characteristics. Another advantage is that the rinsing step after washing can be simplified. Of these, aqueous ammonia is particularly preferred. The residual cleaning solution can be particularly reduced, and the rinsing step after cleaning can be significantly simplified. Further, it is easy to control the concentration of the cleaning liquid and the like, and it is possible to reduce the variation in the processing due to the fluctuation of the cleaning liquid composition.

As the alkaline cleaning solution in the present invention,
A solution containing electrolytic cathode water can also be used. Electrolytic cathode water refers to a liquid generated on the cathode side when, for example, pure water or water containing ammonium ions is electrolyzed. Since the electrolytic cathode water has a high reducing property due to the active hydrogen generated at the cathode, both the surface potential of the ferroelectric film and the surface potential of the etching residue can be negatively charged without deteriorating the surface of the ferroelectric film. Thereby, the etching residue can be effectively removed.

Electrolytic cathode water has a smaller etching effect on a silicon oxide film and the like than ammonia water and the like. Therefore, when it is necessary to minimize dissolution of the silicon oxide film and surface modification, use the electrolytic cathode water. It is desirable to do. For example, in the manufacturing process of a capacitive element,
In cleaning after the formation of the ferroelectric film and the electrodes sandwiching it,
Cleaning is often performed with the silicon oxide film (interlayer insulating film) exposed. If it is desired to particularly suppress the dissolution of the silicon oxide film, it is desirable to use electrolytic cathode water. In the manufacture of DRAM and the like, an SOG (SpinOnGlass) film or an HSQ (HydrogenSilis) is used as an interlayer insulating film.
Low dielectric constant films such as esquioxane) films are often used.
Although the SOG film and the HSQ film have an advantage that the capacitance between wirings can be reduced because of their low dielectric constant, they also have a problem that their resistance to a chemical solution is low. For this reason, SOG
When a film or the like is used as an interlayer insulating film, SO
Problems such as etching of the surface of the G film or the like and modification of the surface to increase the dielectric constant may occur. Therefore, in such a case, it is desirable to use electrolytic cathode water.

As a generator for obtaining electrolytic cathode water, a two-tank electrolysis type apparatus is generally used (1).
Electrochemical Handbook, 4th Edition, p. 277 etc.).
Raw water of electrolytic cathode water, that is, pure water or water containing a small amount (0.5% by weight or less) of ammonium ions is sent to each electrolytic cell, where it is electrolyzed by applying a DC voltage. Since the electrolytic cathode water obtained from the cathode side has a high reducing property due to active hydrogen generated at the cathode, etching residues can be effectively removed without adversely affecting the ferroelectric film, the SOG film and the like.

As the alkaline cleaning solution in the present invention,
Those containing a chelating agent can be used. The chelating agent refers to a compound having the ability to form a chelate complex with a metal or metal oxide, particularly an etching residue. Specifically, ethylenediaminetetraacetic acid (EDT
A), trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentaacetic acid (DTPA), N- (2-
(Hydroxyethyl) ethylenediamine-N, N ′, N ′
-Compounds such as triacetic acid (EDTA-OH), or salts thereof. When a salt is used, a salt that does not adversely affect the characteristics of the semiconductor device is preferable, and a salt that does not contain a metal such as an ammonium salt is particularly preferable. The content of the chelating agent is preferably 1 to 10,000 ppm, more preferably 10 to 1,0 ppm with respect to the alkaline washing liquid.
00 ppm. If the concentration is too low, a sufficient chelating effect cannot be obtained. Conversely, if the concentration is too high, organic substances remain on the substrate surface, deteriorating the performance of the semiconductor device, and costly waste liquid treatment is required. The use of such a chelating agent not only enhances the effect of removing the etching residue, but also can effectively prevent reattachment of the etching residue once removed.

When performing the cleaning of the present invention, ultrasonic waves may be applied. By doing so, the cleaning effect may be further enhanced. In this case, the frequency of the ultrasonic wave is preferably 800 kHz or more. 800k
If the frequency is lower than Hz, the wafer may be damaged, and the cleaning action by the ultrasonic wave may not be sufficiently obtained.

In the cleaning in the present invention, various cleaning methods can be applied. For example, dipping, spraying, roll coating, spin coating, or other mechanical methods can be used.

Next, as a preferred embodiment of the present invention,
The cleaning after patterning a ferroelectric film formed on a semiconductor substrate by dry etching will be described as an example.

(First Embodiment) The present inventors have found that the property deterioration of a ferroelectric film caused during cleaning is greatly related to the dissolution of the ferroelectric film by a chemical solution.
It has been found that this dissolution reaction depends on the pH (or hydrogen ion concentration or hydroxide ion concentration) of the chemical solution. Based on this knowledge, the dissolution reaction related to cleaning can be compared with experimental results by chemical equilibrium analysis, chemical reaction rate analysis, and other chemical reaction analysis methods to dissolve oxides. A dissolution amount calculation formula for calculating the amount was derived. By using the formula for calculating the amount of dissolution for setting the chemical solution conditions for cleaning the metal oxide film, effective cleaning can be performed without deteriorating the characteristics of the ferroelectric film.

First, the equation for calculating the amount of dissolution used for setting the washing conditions in this embodiment will be described.

The solubility product (K _S ) can be used as a measure of the solubility of a sparingly soluble salt in a solution. In the case of a metal oxide (M ₁ O _m ), the solubility product (K _S ) Hydroxide (M (OH) _m , m = 1, 2,...)
By examining the solubility product of, its solubility can be estimated. In the case of a complex oxide, it is necessary to consider the solubility product of each hydroxide according to the oxidation state of the metal. Equation (1) represents a chemical equilibrium relationship in a metal hydroxide dissolution reaction. Equation (2) is the solubility product (K _S ) of the metal ion (M ^{m +} ) constituting the salt.
And the concentration of hydroxide ion (OH ⁻ ).
Further, the solubility product (K _S ) can be transformed into Equation (5) by substituting the water dissociation constant (K _W ) and ph given by Equations (3) and (4). Here, K _W is a constant (equilibrium constant) determined by temperature, and changes in standard enthalpy (ΔH ^O ), standard entropy (ΔS ^O ),
It can be determined from the absolute temperature (T). Equation (5) is
It represents the saturation concentration of metal ions generated by dissolution of metal hydroxide, that is, it can be regarded as the saturated solubility of metal hydroxide. FIG. 1 shows the relationship between the saturated dissolved amount of the basic oxide obtained based on the formula (5) and the pH of the solution. In general, the amount of oxide dissolved strongly depends on the pH of the solution.

[0043]

(Equation 1)

On the other hand, the reaction rate (r _V ) of a chemical reaction generally depends on the concentration of a substance in a reaction system, and experimentally, the concentration ([X], [Y]. The product of the constant (k) is expressed by equation (6). In the dissolution reaction, if only the positive reaction is considered, the dissolution amount (w) is given by the product of the dissolution rate (r) and the time (t) in equation (7). In this case, the saturated dissolution amount is approximated by the integral value of the dissolution rate (r) in the reaction time required to reach equilibrium. By comparing the saturated dissolved amount obtained by this integration with the saturated dissolved amount represented by the formula (5), a dissolved amount calculation formula (W ₁ ) is derived as in the formula (8). In equation (8), ph is a variable, α, β
Is a constant determined by conditions such as an object to be cleaned, a chemical solution component, and temperature.

[0045]

(Equation 2)

The above is a description in particular of the case where the chemical equilibrium of the metal hydroxide is represented by the formula (1). Depending on the type of the metal hydroxide, the chemical equilibrium of the formula (9) may be used. Reaction occurs and the hydroxy complex (M (OH)
_{(m + n-1)} ^n-1 ) may be generated. In this case, the concentration of the hydroxy complex present in the solution ([M (OH)
_{(m + n-1)} ^n-1 ]) is given by equation (10). K _Sn is an equilibrium constant in the equilibrium. Therefore, the total concentration of the hydroxy complex in the solution (Σ [M (O
H) _{(m + n-1)} ^n-1 ]) is given by the formula (11), and gives the amount of metal hydroxide dissolved in the dissolution reaction. Similarly to the equation (8), the equation for calculating the amount of dissolution (W _n ) is defined in the equation (12). Note that in the equation (12), n = 1 is obtained by the equation (8)
Is equivalent to

[0047]

(Equation 3)

Next, a description will be given of a method of determining the chemical solution condition and the chemical solution replenishment amount using the above formula.

In setting the above chemical solution conditions, it is particularly important.
What is performed is the pH condition of the drug solution. This pH condition is
Predict the allowable amount of dissolution so that the characteristics of the oxide film do not deteriorate.
Calculated using the above formula for calculating the amount of dissolution.
Is done. 2 (a) and 2 (b) show equations (8) and (8), respectively.
Of the ferroelectric film obtained by using the dissolution amount calculation formula of (12)
FIG. 3 is a diagram illustrating a relationship between a dissolution amount (W) and a pH of a chemical solution. FIG. 2 (a),
In FIG. 2B, W ^*Is the allowable dissolution amount of the ferroelectric film.
You. When equation (8) is used to calculate the pH condition,
Set pH condition of chemical solution to W^*(FIG. 2 (a))
pH^*) To suppress degradation of the thin film
be able to. Similarly, equation (12) was used for the calculation.
In this case, set the pH condition of the drug solution to pH^* _min≦ pH ≦ pH^* _max
By setting the range, the deterioration of the thin film can be suppressed.
You.

Next, a method for determining the replenishing amount of the chemical solution when pH ^* _min ≦ pH ≦ pH ^* _max is set will be described. This method obtains a mathematical expression expressing the excess or deficiency of the drug solution using one or more variables related to the drug solution,
At the time of cleaning, the variables are controlled based on the above formula so that the amount of dissolution or the degree of damage of the metal oxide film falls within a predetermined range.

First, a chemical solution concentration range corresponding to the set pH condition is determined by chemical equilibrium analysis. For example, chemical solution, in the case of a mixture composed of a plurality of component A, component B, component of FIG. 3 A, the concentration of component B (C _A, C _B) in the relationship diagram, the drug solution concentration range hatched portion Indicated by Further, due to practical problems such as the management and control of the chemical solution, the appropriate concentration range of each component (C _Amin ≦ C _A ≦ C _Amax , C _Bmin ≦ C _B ≦
When (C _Bmax ) is set, the concentration range of the chemical solution is determined within the shaded thick line.

FIG. 4 shows a diagram of the excess (deficient) concentration (C _A ^E , C _B ^E ) and pH fluctuation of each component in the set chemical solution concentration range. By previously calculating the relationship between the excess (insufficient) concentration of each component and the pH fluctuation using the above formula and the analysis, it is possible to predict the replenishment amount of each component suitable for maintaining the concentration of the drug solution. it can. In general, the addition amount (V _X ) of the component X to the chemical solution set to a predetermined concentration (C ^* ) is an excess (insufficient) concentration (C _X ^E ).
Is represented by equation (13). By replenishing the chemical solution using this formula, the pH of the chemical solution falls within an appropriate range, and the amount of the metal oxide film dissolved is equal to or less than the above-mentioned allowable dissolution amount.

[0053]

(Equation 4)

All the values and data used for setting the above-mentioned chemical solution conditions and the optimal amount of chemical solution replenishment are stored in the data processing unit as set values, and the data processing unit sets the chemical solution conditions and the amount of chemical solution replenishment.

Next, an example of a cleaning apparatus which can be suitably used in the cleaning method shown in the above embodiment will be described with reference to FIG.

The cleaning apparatus shown in FIG. 5 includes the following (A) to (D). (A) intermittently or continuously measuring the concentration of a predetermined component contained in a drug solution or the concentration, activity or physical quantity relating to the activity of a chemical species contained in the drug solution. (B) controlling the properties of the drug solution. Data storage means for storing mathematical formulas and predetermined data relating to the chemical solution for the measurement (C) based on the measured values obtained by the measuring means and the mathematical formulas and the predetermined data stored in the data storage means Calculating means for calculating an optimal chemical solution condition; and (D) a chemical solution replenishing device for replenishing a predetermined component of the chemical solution so as to perform cleaning under the optimal chemical solution condition.

The concentration analyzer 13 and the pH analyzer 14 shown in FIG. 5 correspond to the measuring means (A). Further, this device is provided with a data processing unit (not shown), which includes the above (B) and (C). Further, the liquid feed pump 7, the liquid feed pump 8, the on-off valve 5, and the on-off valve 6 correspond to the chemical liquid replenishing means (D).

The chemicals stored in the storage tank 3 and the storage tank 4 are supplied to a liquid feed pump 7, a liquid feed pump 8, an on-off valve 5, and an on-off valve 6, respectively.
And stored in the cleaning tank 16 as the cleaning liquid 1. The control of the supply amount of the chemical solution to the cleaning tank 16 is performed by controlling the chemical solution conditions stored in advance in a data processing unit (not shown) and the cleaning solution 1 monitored as needed by the concentration analyzer 13, the pH analyzer 14, and the temperature analyzer 15. Based on the state, the liquid supply pump 7, the liquid supply pump 8, the on-off valve 5, and the on-off valve 6 are controlled by the data processing unit. Cleaning solution 1
The wafer 2 heated by the heater 10 and having the metal oxide film formed on the surface thereof in the storage tank 16 is cleaned. The cleaning liquid overflowing in the overflow tank 9 is sent to the storage tank 16 via the filter 12 by the liquid sending pump 11, and is used again for cleaning the wafer 2.

(Second Embodiment) As a cause of the deterioration of the characteristics of the ferroelectric film during cleaning, fatigue of a chemical solution is cited. Here, the chemical solution fatigue refers to a change in the concentration of a chemical solution component resulting from a chemical reaction between the ferroelectric film and the chemical solution, and a change in concentration due to volatilization or decomposition of the chemical solution itself. Such a concentration change occurs with the passage of time and the processing time of the object to be cleaned, and when the chemical solution concentration is out of a predetermined condition range due to fatigue of the chemical solution, the cleaning performance decreases, This may cause damage to the ferroelectric film. For example, in the case where the chemical solution is a mixed solution composed of a plurality of components of the acid component C and the alkali component D, the dissociation equilibrium as shown in the formulas (14) and (15) exists independently for the acid component C and the alkali component D. . Further, from the chemical equilibrium of each dissociation component, the concentration balance represented by the equation (16) is established.

[0060]

(Equation 5)

Therefore, if the concentration of any of the components changes during washing, the concentrations of all the components are affected, and the chemical composition changes. In this example, chemical equilibrium analysis, chemical reaction rate analysis,
By collating the analysis results obtained by other chemical reaction analysis methods with the results obtained experimentally, a mathematical formula for predicting and judging the fatigue of the chemical solution is derived, and the mathematical formula is used for the chemical solution condition in cleaning the metal oxide film. By using the setting and the replenishment and management of the chemical solution, effective cleaning can be performed without deteriorating the characteristics of the ferroelectric film.

A description will now be given of equations for predicting and judging fatigue of a chemical used in setting of chemical conditions, replenishment of chemicals, and management of chemicals in the present embodiment.

Assuming that the initial concentration for an arbitrary component X in the chemical solution is CX0, the concentration CX of the component X during the cleaning time t
Is represented by equation (17). F (t) in equation (17) is
This is a function representing the decrease amount of the component X including the cleaning time t as a variable. Experimentally, in many cases, f (t) can be approximated by (Equation 18). γ and τ are constants determined by the cleaning conditions (the cleaning target, the coexisting chemical solution, the temperature, the cleaning processing amount, the cleaning apparatus, etc.). Therefore, the above equations (17) and (18)
The change in concentration of each chemical component over time can be obtained by using
5) From the relationship of the concentration balance obtained by the equation (16), it is possible to predict and judge the fatigue of the chemical solution accompanying the change in the chemical solution composition.

[0064]

(Equation 6)

All values and data used for the setting of the chemical condition, the replenishment of the chemical solution and the management of the chemical solution using a mathematical expression capable of predicting and judging the fatigue of the chemical solution are stored in the data processing section as set values. The setting of the chemical solution replenishment and the chemical solution management is performed by the section.

[0066]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. In FIG. 5, the cleaning liquid 1 is ammonia water, and the storage tank 3 stores commercially available ammonia water for electronic industry (29% by weight), and the storage tank 4 stores ultrapure water. The wafer 2 has a PZT film with a thickness of 300 nm formed on one surface of a 6-inch silicon wafer. When the allowable dissolution amount of the PZT film was 0.01% or less of the film thickness at a liquid temperature of 25 ° C., the pH condition calculated by using the dissolution amount calculation formula was 10 or more. FIG.
The PZT film is washed in the pH range (pH 10) and out of the pH range (pH 6), and the amount of the metal oxide film dissolved in the cleaning solution 1 is determined as a measure of the degree of erosion of the metal oxide film by the chemical solution. The results of the analysis are shown as the relationship between the thickness reduction (%) and the cleaning time (minute). When the cleaning solution adjusted to the pH range was used, no decrease in film thickness of 0.01% or more was observed even in the cleaning time of 60 minutes. In the present embodiment, the dissolution amount calculation formula of the above-mentioned formula (8) is used for setting the chemical solution conditions, and the set values of the dissolution amount calculation formula are α = 10 ^−7.5 , β = 1, and K _W = 10 ^-14 .

(Embodiment 2) FIG. 7 shows a schematic structure of a cleaning apparatus used in this embodiment. The wafer 2 having a metal oxide film formed on its surface is placed on a wafer support 18. The wafer support 17 has a function of depressurizing a contact portion with the wafer 2, and the wafer 2 is fixed to the support by the close contact of the contact portion. Further, the support has a rotation function capable of arbitrarily changing the number of rotations, and can rotate the wafer while being fixed to the support. Chemicals are stored in the storage tank 19, the storage tank 20, and the storage tank 21, and the respective chemicals are sent to the storage tank 22 via the open / close valves 23, 24, and 25 and mixed. The on-off valve 23, the on-off valve 24, and the on-off valve 25 are controlled by a data processing unit (not shown), and the respective chemicals are mixed at a predetermined mixing ratio. The mixed liquid stored in the storage tank 22 is monitored by a pH analyzer 28 and a concentration analyzer 29, and is supplied to a liquid sending pump 26 and a nozzle 31.
Is sprayed onto the wafer 2 via Another chemical solution is stored in the storage tank 33 and monitored by the pH analyzer 30.
It is sprayed on the wafer 2 via the liquid sending pump 27 and the nozzle 32. The film thickness of the metal oxide film formed on the surface of the wafer 2 is monitored as needed by the film thickness analyzer 33. The spray amount and the spray time of each chemical solution from the nozzles 31 and 32 are controlled by a liquid feed pump 26 and a liquid feed pump 27 which are controlled by a data processing unit (not shown).

An example of a cleaning method using this apparatus will be described below.
This will be described with reference to the drawings.

In FIG. 7, the storage tank 18 has a commercially available electronic device.
Industrial ammonia water (29% by weight) is stored in the storage tank 19.
Commercially available hydrogen peroxide solution for electronics industry (30% by weight)
Ultrapure water is stored in the tank 20, and
The mixed solution is used for cleaning the metal oxide film. Wafer 2
SiO on both sides of 6 inch silicon wafer_Two100n film
m. When the liquid temperature is 65 ° C,
[NH_Three] = 0.06-1.2 M, [H_TwoO_Two] = 1.6
In the M concentration range, the ferroelectric film was cleaned. Washing
The allowable dissolution amount of the membrane at a purification time of 10 minutes is 1 ± 0.1 nm.
If, and the drug solution obtained by using the dissolution amount calculation formula
The hydroxide ion concentration range is [OH^-] = 3.7-4.
5 × 10^-FourM. FIG. 8 shows the range of the drug solution concentration.
[NH _Three] = 0.6M, [H_TwoO_Two] = 1.6M,
[OH^-] = 4.3 × 10^-FourAfter washing under the condition of M
In this case, the relationship between the thickness reduction (nm) and the cleaning time (minute)
Out of the chemical concentration range ([NH_Three] = 0.06M, [H_TwoO
_Two] = 1.6 M, [OH^-] = 1.1 × 10^-FourM, and
[NH_Three] = 1.2M, [H_TwoO_Two] = 1.6M, [O
H^-] = 6.5 × 10^-FourM) is shown in comparison with the case. This
When using a cleaning solution adjusted to the chemical solution concentration range,
In the cleaning time of 10 minutes, the thickness reduction amount is 1 ± 0.1 nm.
Was controlled in the range. In the present embodiment, the expression (7)
Use the dissolution amount calculation formula to set the chemical solution conditions, and
Class X is OH^-And OH in calculation^-O instead of concentration
H^-And the reaction rate constant was k = 295 (nm
l · min^-1・ Mol^-1). According to the present embodiment,
Method and apparatus for cleaning oxide film in first embodiment
In addition to the arrangement, the following effects can be obtained. That is,
Because a new chemical solution is used for each wafer,
Due to the deterioration of the chemical performance due to the increase and impurities accumulated in the chemical
This has the effect that no recontamination of the wafer occurs. Ma
In addition, the amount of chemical used for cleaning is small, so the amount of chemical used
Also, there is an effect that the amount of chemical liquid waste can be reduced.

(Embodiment 3) In FIG. 5, the cleaning liquid 1 is a mixed liquid of ammonia and hydrogen peroxide, and the storage tank 3 contains commercially available ammonia water (29% by weight) for the electronic industry, and the storage tank 4 contains Commercially available hydrogen peroxide solution for electronic industry (30% by weight)
However, ultrapure water is stored in separate storage tanks (not shown). The wafer 2 is obtained by forming a Pt film with a thickness of 200 nm on one surface of a 6-inch silicon wafer, and further forming a PZT film with a diameter of 120 mm on the Pt film with a thickness of 300 nm. When the initial temperature of each chemical solution is 0.6 M ammonia and 1.6 M hydrogen peroxide at a solution temperature of 65 ° C., respectively, the change in the hydrogen peroxide concentration accompanying the cleaning of the wafer 2 can be calculated by using equation (17). The curve 1 shown in FIG. Expression (18) was used as a function f (t) representing the amount of component decrease in Expression (17), and the set values of the expression were set to γ = 0.04 and τ = 0.8, respectively. further,
FIG. 9 plots a change in the concentration of hydrogen peroxide when the wafer 2 is actually cleaned under the above-described chemical solution conditions, and a change in the concentration of hydrogen peroxide when the chemical solution is appropriately replenished based on the mathematical formula. did. When the chemical solution was appropriately replenished based on the formula, the hydrogen peroxide concentration could be maintained at almost the initial concentration even in the cleaning time of 60 minutes.

(Example 4) In FIG. 5, the cleaning liquid 1 is a mixture of ammonia and hydrogen peroxide, and the storage tank 3 contains commercially available ammonia water for electronic industry (29% by weight). Commercially available hydrogen peroxide solution for electronic industry (30% by weight)
However, ultrapure water is stored in separate storage tanks (not shown). The wafer 2 is a 6-inch silicon wafer having a SiO2 film formed on both sides with a thickness of 100 nm. It is. When the initial temperature of each chemical solution is 0.6 M ammonia and 1.6 M hydrogen peroxide at a solution temperature of 65 ° C., the change in the ammonia concentration accompanying the cleaning of the wafer 2 is shown in FIG. The result is curve 2 shown in FIG.
Note that a function f representing the amount of decrease in the component in equation (17)
Equation (18) was used as (t), and the set values of the equation were γ = 0.16 and τ = 0.2, respectively. Further, FIG.
FIG. 3 plots the change in the ammonia concentration when the wafer 2 is actually cleaned under the above-described chemical solution conditions, and the change in the ammonia concentration when the chemical solution is appropriately replenished based on the mathematical formula. When the chemical solution was appropriately replenished based on the formula, the ammonia concentration could be maintained at almost the initial concentration even during the cleaning time of 180 minutes.

[0072]

As described above, according to the present invention, the properties of a chemical solution are controlled using a predetermined mathematical formula, so that setting, maintenance, and management of optimal chemical solution conditions according to a processing target are performed. Thus, effective cleaning can be performed without deteriorating the characteristics of the object to be cleaned.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the pH of a chemical solution and the amount of a saturated solution.

FIG. 2 is a diagram for explaining a method for determining an optimum pH of a chemical solution.

FIG. 3 is a diagram showing a concentration range of a chemical solution corresponding to a set pH condition.

FIG. 4: Excessive (insufficient) concentration of each component of the chemical solution and pH
It is a diagram of fluctuation.

FIG. 5 is a diagram showing a schematic structure of a cleaning device of the present invention.

FIG. 6 is a diagram showing a relationship between a cleaning time and a thickness reduction amount of a ferroelectric film.

FIG. 7 is a view showing a schematic structure of a cleaning device of the present invention.

FIG. 8 is a diagram showing a relationship between a cleaning time and a thickness reduction amount of a ferroelectric film.

FIG. 9 is a diagram showing a relationship between a cleaning time and a change in the concentration of hydrogen peroxide.

FIG. 10 is a diagram showing a relationship between a cleaning time and a change in the concentration of ammonia.

FIG. 11 is a view showing a conventional method for cleaning a semiconductor substrate provided with a ferroelectric film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cleaning liquid 2 Wafer 3 Storage tank 4 Storage tank 5 Opening / closing valve 6 Opening / closing valve 7 Liquid sending pump 8 Liquid sending pump 9 Overflow tank 10 Heater 11 Liquid sending pump 12 Filter 13 Concentration analyzer 14 pH analyzer 15 Temperature analyzer 16 Washing tank 17 Drainage port 18 Wafer support 19 Storage tank 20 Storage tank 21 Storage tank 22 Storage tank 23 Open / close valve 24 Open / close valve 25 Open / close valve 26 Liquid feed pump 27 Liquid feed pump 28 pH analyzer 29 Temperature analyzer 30 pH analyzer 31 Nozzle 32 Nozzle 33 Storage tank 34 Wafer 35 Capacitor element electrode or capacitive insulating film 36 Mask 37 Etching residue

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] October 26, 1999 (1999.10.
26)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

6. A method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, the method comprising cleaning the semiconductor substrate with a chemical reaction between the metal oxide film and the chemical solution. A method for cleaning a semiconductor substrate, comprising: obtaining a mathematical expression expressing a temporal change in composition using a pH value of the chemical solution, and replenishing the chemical solution based on the mathematical expression.

7. A method for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof using a chemical solution , wherein the pH value of the chemical solution at time t ₁ is used to clean the semiconductor substrate at time t ₂ (t
_2> t ₁₎ obtains a formula that expresses the composition of the chemical solution in the method for cleaning a semiconductor substrate which is characterized in that the replenishment of the chemical on the basis of the equation.

8. A semiconductor substrate cleaning method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, wherein a chemical reaction between the metal oxide film and the chemical solution is performed by the chemical solution . A method for cleaning a semiconductor substrate, comprising: obtaining a mathematical expression expressed by using a pH value; and controlling the pH value based on the mathematical expression to control the progress of the chemical reaction during cleaning.

Wherein said metal oxide film, a semiconductor substrate cleaning method according to any of claims 1 to 8, characterized in that a ferroelectric film.

Wherein said ferroelectric layer, a semiconductor substrate cleaning method according to claim 9 which is a film patterned by dry etching.

Wherein said ferroelectric layer, strontium,
Titanium, barium, zirconium, lead, bismuth, a semiconductor substrate cleaning method according to claim 9 or 10, characterized in that a metal oxide containing at least one selected from tantalum.

Claims12The ferroelectric film is made of BST, PZT,
PLZT, SrBi _TwoTa_TwoO₉, And Ta_TwoO_FiveFrom
Characterized in that it is any membrane selected from the group consisting of
Claim9Or103. The method for cleaning a semiconductor substrate according to item 1.

13. The strong semiconductor substrate with a dielectric film is provided on a surface a semiconductor substrate cleaning method for cleaning with a chemical solution, the by chemical reactions that occur between the chemical and the ferroelectric film A method for cleaning a semiconductor substrate, comprising: obtaining a mathematical expression expressing a temporal change in the composition of a chemical solution using one or more variables relating to the chemical solution, and replenishing the chemical solution based on the mathematical expression.

14. The semiconductor substrate provided with a ferroelectric film on the surface a cleaning method of a semiconductor substrate to be cleaned with a chemical solution, the time using one or more variables relating to the chemical at time t ₁ A method of cleaning a semiconductor substrate, comprising: obtaining a mathematical expression representing the composition of the chemical solution at t ₂ (t ₂ > t ₁ ); and replenishing the chemical solution based on the mathematical formula.

15. The semiconductor substrate provided with a ferroelectric film on the surface a cleaning method of a semiconductor substrate to be cleaned with a chemical solution, the chemical reactions that occur between the chemical and the ferroelectric film Cleaning of a semiconductor substrate, wherein a mathematical expression expressed by using one or more variables related to a chemical solution is obtained, and in cleaning, the progress of the chemical reaction is controlled by controlling the variables based on the mathematical formula. Method.

16. The method of cleaning a semiconductor substrate according to claim 1 , wherein the variable is a composition or a temperature of the chemical solution.

17. The variable is a pH value of the chemical solution.
The method for cleaning a semiconductor substrate according to claim 1, 2, 13, 14, or 15 .

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

Further, according to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, the method comprising the step of cleaning a semiconductor substrate between the metal oxide film and the chemical solution. A method for cleaning a semiconductor substrate is provided, wherein a temporal change in the composition of the chemical solution due to a reaction is obtained by using a composition or temperature of the chemical solution to obtain a mathematical expression, and the chemical solution is replenished based on the mathematical expression. You. Also book
According to the invention, a semiconductor substrate having a surface provided with a metal oxide film
This is a method of cleaning a semiconductor substrate by cleaning a plate using a chemical solution.
Reaction between the metal oxide film and the chemical solution
The change over time of the composition of the drug solution due to the pH value of the drug solution
Find the mathematical expression expressed using, based on the mathematical formula
Cleaning method of semiconductor substrate characterized by replenishing chemical solution
A law is provided. Further, according to the present invention, a ferroelectric
Semiconductor for cleaning semiconductor substrate with film using chemical solution
A method of cleaning a body substrate, wherein the ferroelectric film and the chemical
Over time in the composition of the drug solution due to the chemical reaction occurring between
Is expressed using one or more variables related to the chemical solution.
Obtain the expressed mathematical formula, and replenish the chemical based on the mathematical formula.
And a method for cleaning a semiconductor substrate, comprising:
It is.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015] Further, according to the present invention, a semiconductor substrate having a metal oxide film is provided on a surface a semiconductor substrate cleaning method for cleaning with a chemical solution, the composition of the chemical solution at time t ₁
Alternatively, there is provided a method for cleaning a semiconductor substrate, wherein a formula expressing the composition of the chemical solution at time t ₂ (t ₂ > t ₁ ) is obtained using a temperature, and the chemical solution is replenished based on the mathematical formula. Is done. Furthermore, according to the present invention, gold
Cleaning a semiconductor substrate provided with a metal oxide film using a chemical solution
A semiconductor substrate cleaning method that, drugs at time t ₁
At time t ₂ (t ₂ > t ₁ ) using the pH value of the liquid,
Obtain a formula expressing the composition of the drug solution, based on the above formula
Washing the semiconductor substrate, wherein the chemical solution is replenished.
A cleaning method is provided. Furthermore, according to the present invention,
Cleaning a semiconductor substrate provided with a dielectric film using a chemical solution
A semiconductor substrate cleaning method that, drugs at time t ₁
The time t ₂ (t ₂ >) using one or more variables relating to the liquid.
A mathematical expression expressing the composition of the chemical solution at t ₁ ) is obtained,
Replenishing the drug solution based on the formula,
A method for cleaning a semiconductor substrate is provided.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

Further, according to the present invention, there is provided a method for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof using a chemical solution, the method comprising the step of cleaning a semiconductor substrate between the metal oxide film and the chemical solution. A semiconductor characterized in that the reaction is determined by using a composition or temperature of the chemical solution to obtain a mathematical expression, and in cleaning, the progress of the chemical reaction is controlled by controlling the composition or temperature of the chemical solution based on the mathematical expression. A method for cleaning a substrate is provided. According to the present invention,
Cleaning a semiconductor substrate provided with a metal oxide film using a chemical solution
A method for cleaning a semiconductor substrate, comprising:
The chemical reaction that takes place between the chemical and the pH value of the chemical
The mathematical expression expressed by using the above formula is obtained, and upon washing, the mathematical expression
And controlling the pH value to control the chemical reaction.
Method for cleaning a semiconductor substrate, characterized by controlling progress
Is provided. According to the invention, a ferroelectric film is formed on the surface.
For cleaning a semiconductor substrate provided with a substrate using a chemical solution
A method of cleaning a substrate, wherein the ferroelectric film and the chemical
The chemical reaction occurring between one or more of the chemicals
The formula expressed by using the variables of
Controlling the variables based on mathematical formulas
Washing of a semiconductor substrate characterized by controlling the progress of the reaction
A cleaning method is provided.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

According to the present invention, there is provided a semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof by using a chemical, wherein (A) the concentration of a predetermined component contained in the chemical or the chemical Measuring means for intermittently or continuously measuring the concentration, activity or physical quantity related to the activity of the chemical species to be measured, and (B) storing mathematical formulas for controlling the properties of the chemical solution and predetermined data related to the chemical solution. Data storage means, and (C) arithmetic means for calculating an optimum chemical solution condition based on the measured value obtained by the measurement means and the mathematical formula and the predetermined data stored in the data storage means, (D) the optimum as washing with liquid condition is performed, Mochiiruko cleaning device, a semiconductor substrate, characterized in that a chemical replenishment means for performing a replenishment of a predetermined component of the chemical
Can be.

Claims (14)

[Claims] 1. A method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, wherein the metal oxide film is formed by a chemical reaction occurring between the metal oxide film and the chemical solution. An amount expressing the amount of the film dissolved using one or more variables related to the chemical solution is determined, and upon cleaning, the amount of the metal oxide film dissolved is within a predetermined range. Cleaning the semiconductor substrate by controlling the above variables. 2. A method for cleaning a semiconductor substrate provided with a metal oxide film on a surface thereof using a chemical solution, wherein the metal oxide film is formed by a chemical reaction occurring between the metal oxide film and the chemical solution. Obtain a mathematical expression expressing the degree of damage to the film using one or more variables related to the chemical solution, and upon cleaning, based on the mathematical expression, so that the degree of damage to the metal oxide film falls within a predetermined range. A method for cleaning a semiconductor substrate, wherein the variable is controlled. 3. A method for cleaning a semiconductor substrate having a surface provided with a metal oxide film using a chemical solution, wherein the semiconductor substrate is provided with a metal oxide film, wherein the chemical solution is caused by a chemical reaction between the metal oxide film and the chemical solution. A method for cleaning a semiconductor substrate, comprising: obtaining a mathematical expression expressing a temporal change in composition using one or more variables relating to the chemical solution, and replenishing the chemical solution based on the mathematical expression. 4. The semiconductor substrate of a metal oxide film is provided on the surface a cleaning method of a semiconductor substrate to be cleaned with a chemical solution, the time using one or more variables relating to the chemical at time t ₁ t _{2. A} method of cleaning a semiconductor substrate, comprising: obtaining a mathematical expression representing the composition of the chemical solution at (t ₂ > t ₁ ), and replenishing the chemical solution based on the mathematical formula. 5. A method for cleaning a semiconductor substrate provided with a metal oxide film on a surface using a chemical solution, wherein a chemical reaction occurring between the metal oxide film and the chemical solution is applied to the chemical solution. A method of cleaning a semiconductor substrate, wherein a mathematical expression expressed by using one or more variables is obtained, and in cleaning, the progress of the chemical reaction is controlled by controlling the variables based on the mathematical expression. 6. The method for cleaning a semiconductor substrate according to claim 1, wherein said metal oxide film is a ferroelectric film. 7. The method according to claim 6, wherein the ferroelectric film is a film patterned by dry etching. 8. The ferroelectric film according to claim 6, wherein the ferroelectric film is a metal oxide containing at least one selected from strontium, titanium, barium, zirconium, lead, bismuth, and tantalum. A method for cleaning a semiconductor substrate. 9. The ferroelectric film is made of BST, PZT, PZT,
The method for cleaning a semiconductor substrate according to claim 6, wherein the film is any one selected from the group consisting of LZT, SrBi ₂ Ta ₂ O ₉ , and Ta ₂ O ₅ . 10. The method for cleaning a semiconductor substrate according to claim 1, wherein the chemical liquid is an alkaline cleaning liquid having a pH of 8 or more. 11. The method according to claim 1, wherein the variable is a composition or a temperature of the chemical solution. 12. The semiconductor according to claim 1, wherein the variable is a concentration of a predetermined component contained in the chemical solution or a concentration, activity or physical quantity related to activity of a chemical species contained in the chemical solution. Substrate cleaning method. 13. The method according to claim 1, wherein the variable is a pH value of the chemical solution. 14. A semiconductor substrate cleaning apparatus for cleaning a semiconductor substrate provided with a metal oxide film on its surface using a chemical, comprising: (A) a concentration of a predetermined component contained in the chemical or a chemical species contained in the chemical. Measurement means for intermittently or continuously measuring the concentration, activity or physical quantity related to the activity,
(B) data storage means for storing a mathematical formula for controlling the properties of the chemical solution and predetermined data relating to the chemical solution; (C) a measured value obtained by the measuring means; and the data stored in the data storage means. Calculating means for calculating an optimum chemical solution condition based on a mathematical formula and the predetermined data; and (D) a chemical solution replenishing device for replenishing a predetermined component of the chemical solution so as to perform cleaning under the optimum chemical solution condition. An apparatus for cleaning a semiconductor substrate, comprising: