JP6281283B2 - Polymer thin film structure and organic film depth analysis method - Google Patents

Description

  The present invention relates to a polymer thin film structure and an analysis method in the depth direction of an organic film. Specifically, the time-of-flight secondary ion mass spectrometry (TOF-SIMS) is used to analyze the distribution of trace components that are unevenly distributed near the surface of a polymer thin film structure or organic film. It relates to an analysis method to be used and evaluated.

  The properties of functional materials such as organic thin films and polymer thin films vary greatly depending on the material surface, the composition at the substrate interface, the layer separation state, and the like. In particular, in functional organic materials such as liquid crystal alignment films, antireflection films for semiconductor lithography, and organic EL materials, additives such as additives that impart properties such as alignment characteristics, lithography characteristics, and surface liquid repellency are provided on the outermost surface of the material. The composition and internal distribution state are greatly involved in the expression of the function. Therefore, it is indispensable for the development of functional organic materials to evaluate the distribution of such substances in the depth direction from the material surface.

  Conventionally, when acquiring such information, cross-sectional observation with a scanning electron microscope (SEM) or a transmission electron microscope (TEM), Rutherford Backscattering Spectroscopy (RBS), For example, composition analysis in the depth direction by X-ray reflection method (XRR) has been used. However, in these analytical methods, it is necessary that the analysis target has a different chemical bonding state or element from other components that become discriminating factors, and that such discriminating factors must be contained in percent order. was there. However, depending on the material, there is a case where it is very difficult to analyze the composition in the depth direction or the layer separation structure because it does not have such a discrimination factor or its amount is very small.

Further, analysis in the surface / depth direction by X-ray photoelectron spectroscopy (XPS) is also used as an analysis method of a layer separation structure of a thin film structure.
XPS allows not only elemental composition analysis but also identification and quantification of functional groups, but as described above, it does not contain trace chemical components less than a percent order or characteristic chemical bonding states that change chemical shifts. In some cases, clear identification and quantification were difficult. In order to solve such a problem, a derivatized XPS method in which a functional group is chemically modified has been reported (Non-Patent Documents 1 and 2). According to this method, a reagent containing a heteroatom such as fluorine or chlorine having a large photoionization cross-sectional area is selectively reacted with a specific functional group, and this heteroatom is detected to identify and quantify a trace component. It can be done. However, because there are limited labeling reagents and reaction conditions that react specifically with specific functional groups, some functional groups that can analyze the distribution state and layer structure of the thin film structure in the depth direction by the derivatization XPS method are included. It is limited and is not necessarily a versatile technique, and it is difficult to analyze a blend material of compounds having the same or similar functional groups.

  In XPS, the detectable depth is about 5 to 10 nm, and it is difficult to evaluate the composition distribution in the depth direction of a region shallower than this. In order to solve such a problem, the angle-resolved XPS method (AR−) is used to measure the surface region in a stepwise manner while maintaining the chemical bonding state of the original sample by changing the detection angle of photoelectrons. XPS) depth direction analysis is performed. Further, in RBS, it is possible to analyze the depth direction of elements in the surface region by measuring the energy spectrum of scattered ions generated by ion beam irradiation. However, both XPS and RBS cannot be detected unless the material to be analyzed contains several percent or more in the material, and are not suitable for evaluating the distribution state of trace components.

Further, secondary ion mass spectrometry (SIMS) is also exemplified as a surface / depth analysis method, which has been widely used in the field of inorganic materials such as semiconductors.
SIMS is classified into Dynamic-SIMS (D-SIMS) and Static-SIMS (S-SIMS) mainly depending on the dose of primary ions.

D-SIMS is a method of generating secondary ions by sputtering a sample surface by irradiation with a primary ion beam, and this enables elemental analysis in the depth direction.
However, in the depth direction analysis by D-SIMS, since the molecular structure is destroyed by sputtering, it is difficult to perform measurement while maintaining the original structure. In addition, since it does not have a characteristic molecular structure, it may not be distinguished from other components. Therefore, it was not suitable for the analysis of organic matter.

  On the other hand, S-SIMS generates fragment ions and molecular ions (secondary ions) having chemical structure information on the sample surface by irradiation with a small amount of pulsed primary ions, and measures the mass by a mass spectrometer. This is a method for examining what components (atoms and molecules) exist on the outermost surface of the solid sample.

  S-SIMS is mainly performed using a time-of-flight (TOF) mass spectrometer (TOF-SIMS). As a highly sensitive mass spectrometry and surface analysis method, the field of biological samples and electronic materials is used. Has come to be widely used. One reason for this is that since the amount of primary ion irradiation is extremely small, the organic compound is ionized while maintaining its chemical structure, and the structure of the organic compound can be known from the mass spectrum. For this reason, TOF-SIMS is excellent in the evaluation of organic films.

In TOF-SIMS, secondary ions released under the condition that the amount of primary ions irradiated onto a sample is suppressed as much as the object of analysis, the current density of the primary ions is 5 digits or more smaller than that of D-SIMS. In S-SIMS, the total dose of primary ions is usually 10 ¹² ions / cm ² or less, and the probability that primary ions hit the same location twice or more is extremely low. Under such conditions, in addition to the ionization of atoms and molecules that make up the solid, the probability that a relatively weak bond in the compound molecule adsorbed on the sample surface breaks and desorption occurs increases, and the interatomic bond is maintained. The remaining molecular ions and fragment ions are generated and released. As a result, in addition to the elemental composition, the TOF-SIMS measurement provides information on molecules and chemical structures in a very shallow region of the surface that could not be handled by D-SIMS.
However, in TOF-SIMS, since the irradiation amount of primary ions is smaller than that of D-SIMS and the sputtering rate is very slow, it is theoretically difficult to analyze in the depth direction.

  As a solution to such a problem, in recent years, by measuring the cutting surface by cutting a cross section by a precision oblique cutting method using a microtome (Patent Document 1) or SAICAS (Cycus: manufactured by Daipura Wintes) (Non-Patent Document 3), A method for directly acquiring information in the depth direction without sputtering has been proposed. As a result, the molecular structure of the target component can be traced in the depth direction without being affected by fragmentation by sputtering.

  On the other hand, in the research and development of materials and elements such as electronic devices, sensors, storage media, etc., the miniaturization of structures, the combination of materials, and the advancement of functions have progressed, and thinning of liquid crystal alignment films and semiconductor materials is required. Has been. However, in the case of an ultrathin film, it is very difficult to analyze the depth direction using a precision oblique cutting method using a microtome or SAICAS. Further, since the measurement surface is in direct contact with the cutting edge, there is a concern about contamination from the cutting edge. Furthermore, it is a technique that requires skill even if it is a thin film with a certain thickness rather than an ultra-thin film. Depending on the characteristics of the material, even if it has a thickness on the order of μm, the cut surface is wavy and a smooth cut surface is obtained. There is a problem that it is often not possible.

In recent years, each ion beam can be individually optimized by using a dual beam method in which a primary ion beam for measurement and a sputter ion beam for sputtering are used together. Therefore, the depth is excellent in horizontal resolution and mass resolution by TOF-SIMS. Direction analysis became possible.
However, in this case, since the molecular structure is destroyed by sputtering as in D-SIMS, there is a problem that it is difficult to perform measurement while maintaining the original structure.
Furthermore, in the depth direction analysis by TOF-SIMS, there is a transition region where the secondary ion yield is not stable immediately after the start of etching by sputter ions. For this reason, it is very difficult to evaluate the distribution state of the target substance in the vicinity of the surface of the material. In addition, as the sample is easily charged, the width of the transition region becomes wider, which makes it difficult to analyze the depth direction in the vicinity of the surface of the organic film.

JP 2004-219261 A

Batich, C.D., Appl.Surf.Sci., Vol. 32, pp. 57-73 (1988) Nakayama, Y. et al., J. Polym. Sci. A, Polym. Chem., Vol. 26, pp. 559-572 (1988) Itoh, H., J. Surf. Anal., Vol. 15, pp. 235-238 (2009)

  The present invention has been made in view of the above problems, and provides an analysis method for simply and accurately analyzing a distribution state of a component in a depth direction and a layer separation structure in a polymer thin film structure. Objective. It is another object of the present invention to provide a method for simply and accurately analyzing the distribution state of trace components unevenly distributed near the surface of an organic film.

  As a result of intensive investigations to achieve the above object, the present inventors have found that at least one polymer compound is stable isotope even in a polymer thin film structure containing two or more polymer compounds. Sputtering a polymer thin film structure containing a labeled polymer compound along the depth direction thereof with sputter ions and time-of-flight secondary ion mass spectrometry. The process of obtaining the mass spectrum of the secondary ion is repeated to obtain the depth profile of the fragment containing the stable isotope, thereby simplifying the distribution state and the layer separation state of the constituent components in the polymer thin film structure. And found that it can be analyzed accurately.

  Furthermore, the present inventors have formed a conductive carbon coating layer on the surface of the organic film, sputtered the carbon-coated organic film with sputter ions along its depth direction, and a time-of-flight secondary Obtaining a depth profile of the analyte by repeating the process of obtaining a secondary ion mass spectrum of the analyte in the organic film by ion mass spectrometry, thereby distributing trace components near the surface of the organic film The present invention has been completed by finding that the state can be easily and accurately analyzed.

That is, the present invention
1. An analysis method in the depth direction of a polymer thin film structure,
The polymer thin film structure has a thickness of 10 to 500 nm, and the polymer thin film structure contains two or more kinds of polymer compounds, at least one of which is labeled with a stable isotope,
Sputtering a structure containing a polymer compound labeled with a stable isotope with sputter ions along its depth direction, and a secondary ion containing the stable isotope by time-of-flight secondary ion mass spectrometry And obtaining the depth profile of the fragment containing the stable isotope by repeating the step of obtaining the mass spectrum of the polymer thin film structure in the depth direction,
2. A depth direction analysis method of one polymer thin film structure in which the sputter ions are accelerated to 200 eV to 500 eV,
3. A depth direction analysis method for one polymer thin film structure in which the sputter ion is Cs ⁺ accelerated to 200 eV to 500 eV,
4). An analysis method in a depth direction of the polymer thin film structure according to any one of 1 to 3, wherein the thickness of the polymer thin film structure is 10 to 200 nm;
5. The analysis method in the depth direction of the polymer thin film structure according to any one of 1 to 4, wherein the linking groups contained in the two or more polymer compounds are the same as each other;
6). The depth analysis method of the polymer thin film structure according to any one of 1 to 5, wherein the polymer thin film structure comprises a polymer blend thin film containing two or more kinds of polymer compounds,
7). The analysis method in the depth direction of the polymer thin film structure according to any one of 1 to 6, wherein the polymer thin film structure has a multilayer structure of two or more layers,
8). The depth of the polymer thin film structure according to any one of 1 to 7, wherein the stable isotope is selected from deuterium, carbon 13, nitrogen 15, oxygen 17, oxygen 18, silicon 29, silicon 30, sulfur 33, and sulfur 36 Direction analysis method,
9. Form a conductive carbon coating layer on the surface of the organic film,
Sputtering the carbon-coated organic film with sputter ions accelerated to 200 eV to 500 eV along the depth direction, and time-of-flight secondary ion mass spectrometry, An analysis method in the depth direction of the organic film characterized by obtaining a depth profile of the substance to be analyzed by repeating the step of acquiring a secondary ion mass spectrum,
10. 9. The analysis method according to 9, wherein the sputter ion is Cs ⁺ accelerated to 200 eV to 500 eV,
11. 9 or 10 analysis method in which the conductive carbon coating layer is formed by physical vapor deposition or chemical vapor deposition,
12 11 analysis methods in which the conductive carbon coating layer is formed by a vacuum deposition method;
13. 12 analysis methods whose vacuum degree in the case of vapor deposition is 0.5-10Pa,
14 The analysis method according to any one of 9 to 13, wherein the conductive carbon coating layer has a thickness of 5 to 50 nm.

According to the polymer thin film structure analysis method of the present invention, it is possible to easily and accurately analyze the distribution state of the components in the depth direction and the layer separation structure in the polymer thin film structure. The analysis method of the present invention can also be applied to a thin polymer thin film structure. Moreover, it is suitable as a method for analyzing a distribution state of a component in a depth direction and a layer separation structure in a structure including a polymer blend thin film obtained by blending two or more kinds of polymers.
In the method for analyzing a polymer thin film structure of the present invention, as in the conventional analysis method, the substance to be analyzed has a chemical bond state or an element different from other components, and an element that is such a discrimination factor is added. It is not limited to a polymer thin film structure containing a percentage order, or a polymer thin film structure having a thickness and physical properties capable of precise oblique cutting by a microtome or SAICAS, Since it can be applied to various polymer thin film structures, it can provide more advanced information on polymer thin film structures such as liquid crystal alignment films.

  Further, according to the organic film analysis method of the present invention, by forming a conductive carbon coating layer on the surface of the organic film, the coating layer can be a transition region where the secondary ion yield is not stable. It is possible to analyze the distribution in the depth direction of the analyte in the vicinity of the surface of the organic film under the layer without being affected by the transition region. The conductive carbon coating layer also has an effect of suppressing the charging of the sample.

It is sectional drawing of the two-layer separation structure model sample used by the Example and the comparative example. It is a depth profile of the two-layer separated structure model sample used in Example 1. It is a depth profile of the two-layer separated structure model sample used in Comparative Example 1. It is a depth profile of the two-layer separated structure model sample used in Example 2. It is sectional drawing of the sample which gave the carbon coating used in Example 3. FIG. It is a depth profile by TOF-SIMS of the sample which gave the carbon coating of Example 3. FIG. It is a depth profile by TOF-SIMS of the sample which does not give the carbon coating of the comparative example 3.

  In the method for analyzing a polymer thin film structure of the present invention, the thickness of the polymer thin film structure to be analyzed is 10 to 500 nm, which is difficult to analyze by other methods. Analysis is possible if the thickness is up to μm. According to the analysis method of the present invention, it is possible to analyze even if the polymer thin film structure to be analyzed has a particularly thin thickness of 10 to 200 nm, 10 to 150 nm, and further 10 to 100 nm. .

The polymer thin film structure includes two or more kinds of polymer compounds. According to the analysis method of the present invention, even when the polymer compound contained in the polymer thin film structure has the same chemical bond, structure or element, at least one polymer compound is stable isotope. It is possible to distinguish and analyze each other by labeling with. For example, even polymer compounds having the same linking group such as an amide bond or an ester bond can be identified and analyzed.
According to the analysis method of the present invention, it is not limited to a polymer compound having a specific chemical bond, structure or element, and various polymer compounds can be analyzed.

  The polymer thin film structure may include a polymer blend thin film containing two or more kinds of polymer compounds. The polymer thin film structure may have a multilayer structure of two or more layers.

The stable isotope used for labeling the polymer compound is not particularly limited. For example, deuterium ( ² H (D)), carbon 13 ( ¹³ C), nitrogen 15 ( ¹⁵ N), oxygen 17 ( ¹⁷ O), oxygen ¹⁸ (18 O), silicon ^{29 (29} Si), silicon ^{30 (30} Si), sulfur ³³ (33 S), like sulfur 36 ⁽³⁶ S) and the like. The polymer compound can be labeled using one or more stable isotopes.
The amount of stable isotope used may be determined in consideration of the sensitivity of the detector, the mass resolution, the natural abundance ratio of the stable isotope used, and the like.

  The introduction of the above stable isotope is not an atom that can be lost due to polymerization reaction, condensation reaction, etc. among the constituent atoms of the analysis target substance, but forms an atom that reliably remains in the polymer skeleton to be formed, for example, an imide bond in polyimide It is preferable that the nitrogen atom and the carbon of the main skeleton are the targets for substitution of stable isotopes.

  A conventionally known method may be used for labeling the polymer compound with a stable isotope. For example, the monomer may be labeled with a stable isotope, and then a polymer compound may be synthesized using the labeled monomer, or the polymer may be synthesized using a crosslinking agent or a polymerization initiator labeled with a stable isotope. Compounds may be synthesized. Moreover, when labeling a polymer compound with deuterium, in addition to the above method, it may be labeled by deuterium exchange reaction.

  In the present invention, a step of sputtering a structure containing a polymer compound labeled with a stable isotope with sputter ions along its depth direction, and a secondary ion containing the stable isotope by TOF-SIMS. A depth profile of the fragment containing the stable isotope is obtained by repeating the step of acquiring a mass spectrum.

As the sputter ions used when sputtering the polymer thin film structure, Cs ⁺ , O ₂ ⁺ , Ar ⁺ , C ₆₀ ^{+ and the} like accelerated to about several hundred eV to several keV are generally used. In particular, since organic substances generate a lot of negative ions, Cs ⁺ having an effect of increasing the negative ionization rate is preferable. Further, low acceleration (200 eV to 500 eV) Cs ⁺ with less damage to the polymer material is more preferable. However, this is not the case when the target ion is a positive ion.

Case of analyzing polymeric film structure, the primary ions used in TOF-SIMS, generally Ga ⁺ accelerated to several tens of keV from several keV _{^{to, Au n m +, Bi n}} m +, Ar +, C ₆₀ ⁺ or the like is used. Particularly Au _n ^{m +} is the analysis of organic material such as polyimide which is a cluster ion _{^{source, Bi n m +, C 60}} + , and the like are preferable. In particular, the Bi ion source is more preferably a highly sensitive trimer (Bi ₃ ).

  By repeating the above-described sputtering and TOF-SIMS measurement, the distribution state of the constituent components in the polymer thin film structure in the depth direction can be easily and accurately analyzed.

  The organic film analysis method of the present invention includes a step of forming a conductive carbon coating layer on the surface of the organic film, sputtering the carbon-coated organic film by sputter ions along its depth direction, An organic membrane characterized in that a depth profile of the analyte is obtained by repeating a step of acquiring a secondary ion mass spectrum of the analyte in the organic membrane by temporal secondary ion mass spectrometry. This is an analysis method in the depth direction.

  Examples of the method for forming the carbon coating layer include physical vapor deposition methods such as vacuum deposition and sputtering, and chemical vapor deposition methods such as thermal CVD and plasma CVD. Of these, the vacuum deposition method is particularly preferable.

  When forming a carbon coating layer by a vacuum evaporation method, it can form using a carbon coater or a vacuum evaporation apparatus. As the carbon coater, a non-conductive sample is used for pretreatment of a sample when performing observation or analysis using a charged particle beam device such as a scanning electron microscope (SEM) or an electron probe microanalyzer (EPMA). Similar ones can be used. Therefore, it is not a technique that requires special pre-preparation or skill, and pre-processing can be easily performed in a short time.

The degree of vacuum during vapor deposition is preferably 0.5 to 10 Pa, and more preferably 0.5 to 2 Pa.
The deposition time may be set as appropriate to obtain the desired thickness.

  The thickness of the carbon coating layer only needs to correspond to the thickness of the transition region where the yield of secondary ions is unstable in the early stage of analysis. Specifically, 5 nm or more is preferable. The upper limit of the thickness is not particularly defined, but it is preferably as thin as possible in order to shorten the measurement time and suppress thermal damage due to the formation of the carbon coating layer. For that purpose, the thickness is preferably 50 nm or less, more preferably 40 nm or less, still more preferably 20 nm or less, and particularly preferably 10 nm or less. However, this is not the case when the sputtering rate by TOF-SIMS measurement is fast.

  The carbon source for forming the carbon coating layer is not particularly limited, and examples thereof include graphite (graphite), carbon black, activated carbon and the like, among which graphite (graphite) is preferable. Further, the shape is not particularly limited, and various shapes such as powder, granule, fiber, and core can be adopted. Of these, fiber and core are preferable. The diameter of the fibrous and core carbon is preferably 5 to 10 μm. The purity of carbon is preferably 99.9% or more, and more preferably 99.99% or more.

  The organic film to be analyzed in the present invention is not particularly limited. However, since the sample is irradiated with radiant heat while the carbon coating layer is formed by the above method, it is not suitable for a sample that is weak against heat or a sample that easily generates gas. However, since the radiant heat is assumed to be about several tens of degrees Celsius higher than room temperature, it can be applied to many organic films by using an apparatus equipped with a sample cooling mechanism.

Sputtering ions used for sputtering the organic film are generally Cs ⁺ , O ₂ ⁺ , Ar ⁺ , C ₆₀ ^{+ and the} like accelerated to several hundred eV to several keV. In particular, since organic substances generate a lot of negative ions, Cs ⁺ having an effect of increasing the negative ionization rate is preferable. In particular, low acceleration (200 eV to 500 eV) Cs ⁺ or the like with less damage to organic substances is more preferable. However, this is not the case when the target ion is a positive ion.

If the organic film of interest, primary ions used in TOF-SIMS is typically accelerated to several tens of keV several _{^{keV Ga +, Au n m +}} , Bi n m +, Ar +, C 60 + , etc. Is used. In particular, Au _n ^{m +} , Bi _n ^{m +} , C ₆₀ ^{+ and the} like which are cluster ion sources are preferable for the analysis of organic substances. In particular, the Bi ion source is more preferably a highly sensitive trimer (Bi ₃ ).

  In addition, when the analysis target substance has the same chemical bond or element as the other constituent components, secondary ions generated by sputtering may have the same structure, so the secondary substance derived from the analysis target substance Ions may not be identified.

As a method for solving the above problem, for example, a method of labeling a substance to be analyzed with a stable isotope can be mentioned. This makes it possible to specify secondary ions derived from the analysis target substance.
The stable isotope used for labeling is not particularly limited. For example, deuterium ( ² H (D)), carbon 13 ( ¹³ C), nitrogen 15 ( ¹⁵ N), oxygen 17 ( ¹⁷ O), oxygen 18 ( ¹⁸ O), silicon 29 ( ²⁹ Si), silicon 30 ( ³⁰ Si), sulfur 33 ( ³³ S), sulfur 36 ( ³⁶ S) and the like. The analyte can be labeled using one or more stable isotopes.
The amount of stable isotope used may be determined in consideration of the sensitivity of the detector, the mass resolution, the natural abundance ratio of the stable isotope used, and the like.
A conventionally known method may be used as a method for labeling the substance to be analyzed with a stable isotope.

  By the method described above, the distribution state in the depth direction in the vicinity of the surface of the organic film can be easily and accurately analyzed. The analysis method of the present invention is particularly suitable for analyzing the distribution state in the depth direction in the vicinity of the surface of about 10 nm from the material surface.

  EXAMPLES Hereinafter, although a preparation example, an Example, and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example. The composition ratio (molar ratio) was calculated from the preparation ratio.

As the diamine component to prepare 20mL four-necked flask [Preparation Example 1] thin film-forming composition A, labeled with ¹⁵ N a p- phenylenediamine ^(p-PDA-15 N, manufactured by Aldrich) 0.243 g (2.25 mmol ), 4-octadecyloxy-1,3-diaminobenzene (APC18) 0.094 g (0.25 mmol), N-methyl-2-pyrrolidone (NMP) 3.70 g, and γ-butyrolactone (GBL) 3.70 g were added. , Cooled to about 10 ° C., added 0.485 g (2.50 mmol) of 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), returned to room temperature and allowed to react for 24 hours under a nitrogen atmosphere. A solution having a concentration of 10% by mass of (Polymer A) was obtained. The composition ratio of each structural unit in the polymer A was CBDA: p-PDA- ¹⁵ N: APC18 = 1.0: 0.9: 0.1.
Transfer 8.22 g of the above polymer A solution to a 50 mL Erlenmeyer flask, dilute by adding 2.74 g of GBL and 2.74 g of butyl cellosolve (BC), polymer A is 6% by mass, GBL is 47% by mass, NMP is 27% by mass, A thin film forming composition A having a BC of 20% by mass was prepared.

[Preparation Example 2] thin film-forming composition A 'except that a p-PDA not labeled with instead ¹⁵ N Preparation ^p-PDA-15 N of polymer A in the same manner as in Preparation Example 1' synthesized Then, a thin film forming composition A ′ was prepared. The composition ratio of each structural unit in the polymer A ′ was CBDA: p-PDA: APC18 = 1.0: 0.9: 0.1.

[Preparation Example 3] Preparation of thin film forming composition B As a diamine component, 0.996 g (5.00 mol), 8.23 g of NMP, 8.23 g of GBL were added as a diamine component to a 30 mL four-necked flask. The mixture was cooled to about 10 ° C., 0.902 g (4.60 mmol) of CBDA was added, the temperature was returned to room temperature, and the mixture was reacted under a nitrogen atmosphere for 24 hours to obtain a polyamic acid (polymer B) solution having a concentration of 10% by mass. The composition ratio of each structural unit in the polymer B was CBDA: DADPA = 1.0: 1.0.
15 g of the polymer B solution was transferred to a 50 mL Erlenmeyer flask, diluted by adding GBL5.00 g and BC5.00 g, polymer B was 6% by mass, GBL was 47% by mass, NMP was 27% by mass, and BC was 20% by mass. A thin film forming composition B was prepared.

[Preparation Example 4] Production of Model Sample FIG. 1 is a cross-sectional view of the produced two-layer separated structure model sample. First, the thin film forming composition B was applied onto the ITO substrate 3 by a spin coating method, and a polymer B layer 2 was formed according to the following film forming conditions. After the film formation, the thin film forming composition A is applied onto the polymer B layer 2 by a spin coating method, and the polymer A layer 1 is formed according to the following film formation conditions. A model of a two-layer separation structure for Example 1 A sample was prepared.
Further, a two-layer separated structure model sample for Comparative Example 1 was prepared in the same manner as the above method except that the polymer A ′ layer 1 was formed using the thin film forming composition A ′.

Film forming conditions: First layer (polymer B layer) pre-drying 70 ° C., 70 sec, baking 250 ° C., 10 min, film thickness 120 nm,
Second layer (Polymer A (A ′) layer) Firing at 250 ° C., 10 min, film thickness of 120 nm (total film thickness of 240 nm)

[Example 1, Comparative Example 1]
The two-layer separated structure model sample prepared in Preparation Example 4 is sputtered with sputter ions in the depth direction using TOF-SIMS5 manufactured by ION TOF, and then released from the sample by irradiation with primary ions. TOF-SIMS spectra of secondary ions containing isotopes were obtained in negative ion mode. Bivalent positive ions of bismuth trimer clusters were used as primary ions, and cesium positive ions were used as sputter ions. The sputtering area was 300 μm × 300 μm, and the sputtering analysis area was 100 μm × 100 μm. By repeating sputtering and TOF-SIMS measurement, the distribution of fragment ions by stable isotopes in the depth direction from the sample surface was evaluated.

  The measured value is plotted with the sputter time on the horizontal axis and the secondary ion detection intensity at the sputter time on the vertical axis, and the depth profile is obtained by graphing the relationship between the sputter time and the secondary ion intensity. A two-layer separation structure was evaluated. The measurement conditions for TOF-SIMS are as follows.

Primary ion: 25 keV Bi ₃ ²⁺ , 0.2 pA (pulse current value), random scan mode Primary ion scan range (measurement region): 100 μm × 100 μm
Primary ion pulse frequency: 10 kHz (100 μs / shot)
Primary ion beam diameter: about 5 μm
Secondary ion detection mode: negative
Number of scans: 1scan / cycle
(A flat gun is used for charging correction)
<Sputtering conditions>
Sputter ion: Cs ⁺ (35 nA, 500 eV)
Sputtering area: 300 μm × 300 μm

The result of the model sample using the polymer A which is Example 1 is shown in FIG. 2, and the result of the model sample using the polymer A ′ which is Comparative Example 1 is shown in FIG.
As shown in FIG. 2, in the case of a model sample having a two-layer separation structure using a polymer A into which a stable isotope was introduced, the boundary between the polymer A layer and the polymer B layer was visualized, and the two-layer separation structure could be analyzed. .
On the other hand, as shown in FIG. 3, in the case of a model sample having a two-layer separation structure using polymer A ′ into which no stable isotope was introduced, the boundary between the polymer A ′ layer and the polymer B layer could not be grasped.

  Next, another embodiment in which the technique of the present invention is applied to a structure thinner than the model sample shown in the first embodiment of the present invention will be described below.

As Preparation Example 5] diamine component to prepare 20mL four neck flask having a polymer C, p-PDA- ¹⁵ N (manufactured by Aldrich) 0.243g (2.25mmol), 0.094g (0.25mmol) of APC18, NMP4. 35 g was added and cooled to about 10 ° C., and 0.750 g (2.50 mmol) of 3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinic dianhydride (TDA) was added, The mixture was reacted at 40 ° C. for 16 hours in a nitrogen atmosphere to obtain a 20% by mass solution of polyamic acid (PAA-1).
To 5.44 g of the PAA-1 solution, 12.69 g of NMP was added for dilution, 0.57 g of acetic anhydride and 0.24 g of pyridine were added, and the mixture was reacted at 50 ° C. for 3 hours. The reaction solution was cooled to about room temperature and then slowly poured into 70 mL of methanol cooled to about 10 ° C. with stirring to precipitate a solid. The precipitated solid was recovered, further dispersed and washed twice with 70 mL of methanol, and dried under reduced pressure at 100 ° C. to obtain a white powder of polyimide (polymer C). The composition ratio of each structural unit in the polymer C was TDA: p-PDA- ¹⁵ N: APC18 = 1.0: 0.9: 0.1.

[Preparation Example 6] Preparation of model sample 1 g of the polymer C was dissolved in a mixed solvent of GBL 12.00 g and BC2.22 g to prepare a thin film forming composition C.
FIG. 1 (the same form as in Example 1) shows a cross-sectional view of the produced two-layer separated structure model sample. First, the thin film forming composition B was applied onto the ITO substrate 3 by a spin coating method, and a polymer B layer 2 was formed according to the following film forming conditions. After the film formation, the thin film forming composition C is applied onto the polymer B layer by a spin coating method, and the polymer C layer 1 is formed according to the following film formation conditions. A model sample having a two-layer separation structure for Example 2 Was made.

Film forming conditions: First layer (polymer B layer) pre-drying 70 ° C., 70 sec, baking 250 ° C., 10 min, film thickness 60 nm,
Second layer (polymer C layer) calcination 250 ° C., 10 min, film thickness 60 nm
(Total film thickness 120 nm)

[Example 2, Comparative Example 2]
For the two-layer separated structure model sample prepared in Preparation Example 6, the distribution of fragment ions by stable isotopes in the depth direction from the sample surface was evaluated in the same manner as in Example 1. However, the sputtering area was 200 μm × 200 μm, and the sputtering analysis area was 60 μm × 60 μm. The measurement conditions of TOF-SIMS are as follows.

Primary ion: 25 keV Bi ₃ ²⁺ , 0.2 pA (pulse current value), random scan mode Primary ion scan range (measurement region): 60 μm × 60 μm
Primary ion pulse frequency: 10 kHz (100 μs / shot)
Primary ion beam diameter: about 5 μm
Secondary ion detection mode: negative
Number of scans: 1scan / cycle
(A flat gun and oxygen gas (vacuum level: 1.0 × 10 ^-6 mbar) are used for charging correction)
<Sputtering conditions>
Sputter ion: Cs ⁺ (20 nA, 500 eV)
Sputtering area: 200 μm × 200 μm

The result of the model sample using the polymer C which is Example 2 is shown in FIG.
As shown in FIG. 4, the boundary between the polymer C layer and the polymer B layer was visualized even in the case of a model sample having a two-layer separation structure using a polymer C into which a stable isotope was introduced, and the two-layer separation structure could be analyzed. .
From this, it was proved that the method of the present invention is also suitable for analyzing the layer separation structure of an extremely thin film structure having a film thickness of about 120 nm.

[Preparation Example 7] Synthesis of Oligoaniline Compound An oligoaniline compound represented by the following formula (1) was synthesized according to the method described in International Publication No. 2008/129947.

[Preparation Example 8] Synthesis of charge-accepting dopant A charge-accepting dopant represented by the following formula (2) was synthesized according to the method described in International Publication No. 2006/025342.

[Preparation Example 9] Preparation of Organic Film Forming Material An oligoaniline compound represented by the formula (1) and a charge-accepting dopant represented by the formula (2) at a molar ratio of 1,3-dimethyl- It is dissolved in a mixed solvent of 2-imidazolidinone (DMI) and cyclohexanol (composition ratio = 2: 4 (mass ratio)) to a solid content concentration of 3% by mass, and further 10 Mass% trifluoropropyltrimethoxysilane and phenyltrimethoxysilane (both manufactured by Shin-Etsu Silicone Co., Ltd.) (mass ratio 1: 2) were added to prepare an organic film forming material.

Preparation Example 10 Preparation of Analytical Model Sample As shown in FIG. 1, the organic film forming material prepared in Preparation Example 3 was applied onto the ITO substrate 3 by spin coating, and heat-treated at 220 ° C. for 15 minutes. Thus, an organic film 2 was formed. The thickness of the organic film 2 was 50 nm.
Furthermore, using a carbon coater with a hydrophilic treatment function (CADE-E) manufactured by Meiwa Forsys Co., Ltd., under the conditions of a vacuum degree of 0.5 to 1 Pa, a preheating time of 5 seconds, and a deposition time of 1.8 seconds. A carbon coating layer 1 (thickness: about 35 nm) was formed on the surface of the organic film 2 by the method to prepare a sample for the example. A graphite fiber (manufactured by Meiwa Forsys, Inc., carbon fiber for high purity analysis (trade name)) was used as a carbon source. A sample not subjected to carbon coating was used for a comparative example.

[Example 3, Comparative Example 3]
Using TOF-SIMS5 manufactured by ION TOF, the model samples for the examples and comparative examples are each sputtered with sputtering ions in the depth direction, and then the primary ions are irradiated to release the samples. A TOF-SIMS spectrum of secondary ions derived from the target substance (silane additive) was obtained in negative ion mode. Bivalent positive ions of bismuth trimer clusters were used as primary ions, and cesium positive ions were used as sputter ions. The sputtering area was 200 μm × 200 μm, and the sputtering analysis area was 50 μm × 50 μm. By repeating sputtering and TOF-SIMS measurement, the distribution of the fragment ions derived from the silane additive in the depth direction from the sample surface was evaluated. The measurement conditions of TOF-SIMS in Examples and Comparative Examples are shown below.

Primary ion: 25 keV Bi ₃ ²⁺ , 0.2 pA (pulse current value), random scan mode Primary ion scan range (measurement region): 50 μm × 50 μm
Primary ion pulse frequency: 10 kHz (100 μs / shot)
Primary ion beam diameter: about 5 μm
Secondary ion detection mode: negative
Number of scans: 1scan / cycle
(A flat gun is used for charging correction)
<Sputtering conditions>
Sputtering ions: Cs ⁺ (35 nA, 500 eV)
Sputtering area: 200 μm × 200 μm

  The measured value is plotted with the sputtering time on the horizontal axis and the detected intensity of secondary ions at the sputtering time on the vertical axis, and the depth profile is obtained by graphing the relationship between the sputtering time and the secondary ion intensity. The distribution of additives in the film was evaluated. The result of Example 3 is shown in FIG. 6, and the result of Comparative Example 3 is shown in FIG.

  6 and 7, the horizontal axis (sputtering time) represents the depth from the sample surface, and the vertical axis (detection intensity) represents the concentration of each ion. As is clear from FIG. 6, by focusing on Si, which is a constituent atom of the silane additive, it was possible to analyze the surface uneven distribution state of the silane additive in the organic film.

1 Polymer A (A ′) or Polymer C Layer 2 Polymer B Layer 3 ITO Substrate 4 Carbon Coating Layer 5 Organic Film 6 ITO Substrate

Claims (14)

An analysis method in the depth direction of a polymer thin film structure,
The polymer thin film structure has a thickness of 10 to 500 nm, and the polymer thin film structure contains two or more kinds of polymer compounds, at least one of which is labeled with a stable isotope,
Sputtering a structure containing a polymer compound labeled with a stable isotope with sputter ions along its depth direction, and a secondary ion containing the stable isotope by time-of-flight secondary ion mass spectrometry And obtaining the depth profile of the fragment containing the stable isotope by repeating the step of obtaining the mass spectrum of the polymer thin film structure in the depth direction.   The analysis method in the depth direction of the polymer thin film structure according to claim 1, wherein the sputtering is performed by sputter ions accelerated to 200 eV to 500 eV. The analysis method in the depth direction of the polymer thin film structure according to claim 1, wherein the sputter ions are Cs ⁺ accelerated to 200 eV to 500 eV.   The analysis method in the depth direction of the polymer thin film structure according to any one of claims 1 to 3, wherein the thickness of the polymer thin film structure is 10 to 200 nm.   The analysis method in the depth direction of the polymer thin film structure according to any one of claims 1 to 4, wherein the linking groups contained in the two or more polymer compounds are the same.   The analysis method in the depth direction of the polymer thin film structure according to any one of claims 1 to 5, wherein the polymer thin film structure includes a polymer blend thin film containing two or more kinds of polymer compounds.   The analysis method in the depth direction of the polymer thin film structure according to any one of claims 1 to 6, wherein the polymer thin film structure has a multilayer structure of two or more layers.   The polymer thin film according to any one of claims 1 to 7, wherein the stable isotope is selected from deuterium, carbon 13, nitrogen 15, oxygen 17, oxygen 18, silicon 29, silicon 30, sulfur 33, and sulfur 36. Analysis method of depth direction of structure. Form a conductive carbon coating layer on the surface of the organic film,
Sputtering the carbon-coated organic film with sputter ions accelerated to 200 eV to 500 eV along the depth direction, and time-of-flight secondary ion mass spectrometry, An analysis method in the depth direction of an organic film, wherein the depth profile of the substance to be analyzed is obtained by repeating a step of acquiring a secondary ion mass spectrum. The analysis method according to claim 9, wherein the sputter ions are Cs ⁺ accelerated to 200 eV to 500 eV.   The analysis method according to claim 9 or 10, wherein the conductive carbon coating layer is formed by physical vapor deposition or chemical vapor deposition.   The analysis method according to claim 11, wherein the conductive carbon coating layer is formed by a vacuum deposition method.   The analysis method according to claim 12, wherein the degree of vacuum at the time of vapor deposition is 0.5 to 10 Pa.   The analysis method according to claim 9, wherein the conductive carbon coating layer has a thickness of 5 to 50 nm.

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