JP2009109397A - Surface analysis method - Google Patents

Abstract

The present invention provides a surface analysis method capable of detecting even an adhering substance that adheres to the surface of a sample to be analyzed in a non-uniform or trace state and could not be detected below the lower detection limit. The task is to do.
[Solution] Substances adhering to the sample surface in a non-uniform or trace amount are collected over a wide area from the sample surface, concentrated, and transferred to the adhesive surface of the adhesive substrate. The surface analysis method is characterized in that the substance is analyzed by surface analysis of the adhered adhesive surface.
[Selection] Figure 13

Description

  The present invention relates to a surface analysis method for analyzing a substance by transferring a substance attached to the surface of a sample to be analyzed to an adhesive surface of an adhesive substrate, and analyzing the surface of the adhesive surface to which the substance is transferred. In this case, a substance that adheres unevenly or in a trace amount to the sample surface is collected on the adhesive surface of the adhesive substrate, collected from a wide range of substances and transferred to a high concentration substance. The present invention relates to a surface analysis method for analyzing a substance by surface analysis of a bonded surface.

  Conventionally, as a method for analyzing the surface of a solid sample, X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), time-of-flight secondary ion mass spectrometry ( TOF-SIMS), total reflection infrared spectroscopy (FT-IR ATR method), and total reflection X-ray fluorescence analysis (TREX) are known. Among them, XPS and TOF-SIMS are capable of analyzing metals, inorganic substances, and organic compounds on the surface of solid samples, so the data that can be widely measured are limited to the surface layer number to several tens of nm region. The industrial fields that are widely used as an analysis method for the above and are actually used are diverse, such as those related to polymer films, semiconductors, optical materials, and electronic devices.

  In recent years, the technical trend of XPS analyzers and TOF-SIMS analyzers has become smaller due to the development of irradiation X-ray microbeam technology and primary ion irradiation technology (reduction of ion beams and higher brightness). Improvements in sensitive analytical capabilities in the area have been achieved.

  However, many of the problems with samples that are actually used for surface analysis are due to impurities on the sample surface, such as spots, unevenness, repellencies and residues, poor adhesion, surface cloudiness, wettability changes, and discoloration. And problems such as poor printing. Therefore, analysis in a micro area often leads to investigation of the cause of the defect, but if the adhesion or impurities on the sample surface is an extremely small amount that is undetectable or unevenly scattered, In many cases, it is difficult to investigate the cause of defects.

  Conventionally, to deal with such problems, it has been practical to take measures such as increasing the number of measurement points. In this case, it is needless to say that time and effort are required, and it is a burden on expensive analyzers. There is a problem such as large. However, there have been no examples of studies on this issue so far in the literature and patents.

  From the viewpoint of a surface analysis method for impurities on a wide range of measurement sample surfaces, there is a method for analyzing metal impurities contained on the surface of a semiconductor substrate (see, for example, Patent Document 1).

  This is because the semiconductor thin film and the semiconductor substrate are decomposed with the decomposition solution, and then the decomposition solution is vaporized on the substrate to concentrate and dry the impurities on the semiconductor substrate thin film and the substrate. In this method, analysis is performed by X-ray analysis (TREX).

  Moreover, there exists what changed the analyzer into TOF-SIMS by the said patent content (for example, refer patent document 2).

  However, the impurities in these cases are only for metallic materials and cannot be expanded to other product fields.

The known literature is described below.
JP-A-9-26401 JP 2002-184828 A

  The present invention has been made in consideration of the technical background described above, and is an attached substance that adheres to the surface of the sample to be analyzed in a non-uniform or trace amount state and could not be detected below the lower detection limit. Even if it exists, let it be a subject to provide the surface analysis method which enables detection.

  As means for solving the above-mentioned problem, that is, the invention according to claim 1 transfers the substance adhered to the surface of the sample to be analyzed to the adhesive surface of the adhesive substrate, and performs surface analysis on the adhesive surface to which the substance is transferred. In this case, the surface analysis method is characterized in that the substance is analyzed.

  According to the second aspect of the present invention, a material attached to the surface of the sample to be analyzed is collected over a wide range, concentrated and transferred to the adhesive surface of the adhesive base material, and the adhesive surface on which the substance is transferred at a high concentration is subjected to surface analysis. The surface analysis method according to claim 1, wherein the substance is analyzed.

  The invention according to claim 3 is that the pressure-sensitive adhesive substrate is composed of any one of a pressure-sensitive adhesive (pressure-sensitive adhesive) and a pressure-sensitive adhesive label, tape, or sheet having a pressure-sensitive adhesive surface on one side or both sides. The surface analysis method according to claim 1 or 2, wherein the adhesive surface is free of impurities other than the adhesive composition component.

  In the invention according to claim 4, a peelable substrate is laminated on the pressure-sensitive adhesive surface (pressure-sensitive adhesive) of the pressure-sensitive adhesive substrate, and the peelable substrate contains a silicone component as a release agent. The surface analysis method according to any one of claims 1 to 3, wherein the surface analysis method is a non-peelable substrate or a peelable substrate that does not contain the release agent itself.

  In the invention according to claim 5, the pressure-sensitive adhesive substrate is adhered to the sample surface by being stuck to the bottom surface of a cylindrical roller or a cylinder or a prism member and rolling or pressing several times on the sample surface to be analyzed. The surface analysis method according to claim 1, wherein the substance is analyzed by transferring the substance and analyzing the surface of the adhesive surface onto which the substance is transferred.

The invention according to claim 6 is the surface analysis method according to any one of claims 1 to 5,
XPS (X-ray Photoelectron Spectroscopy) analyzer and TOF-SIMS (Time-of-Flight Secondary Ion)
A surface analysis method using a mass spectrometer.

  According to the present invention, it is possible to easily detect a very small amount on a sample surface, which is difficult to detect by a normal method, or non-uniformly scattered adhered substances. That is, by transferring a wide area of the sample surface to be analyzed by the adhesive base material, the substance adhered to the surface of the sample to be analyzed is concentrated and transferred to the adhesive surface of the adhesive base material, and the substance is transferred. Detection can be facilitated by surface analysis of the adhesive surface.

  Hereinafter, an example of an embodiment of the surface analysis method of the present invention will be described in detail.

  The pressure-sensitive adhesive base material used in the present invention is obtained by applying a pressure-sensitive adhesive (pressure-sensitive adhesive) on a base material of a composite film such as paper, various plastic films, plastic laminated paper, and vapor-deposited film. It may be a pressure-sensitive adhesive tape, label, or sheet in which a pressure-sensitive adhesive (pressure-sensitive adhesive) is applied on one side or both sides that are generally commercially available. Moreover, in order to analyze the substance transferred to the adhesive surface, the adhesive surface before use should have a known composition with as few element components as possible. In general, acrylic adhesives are frequently used. In this case, the element components are C (carbon) and O (oxygen), and therefore, the number of element components is small and suitable.

  In addition, these commercially available adhesive tapes, labels, and sheets have a release liner laminated on the surface of the adhesive layer for the purpose of protecting the adhesive layer until use. A release liner that is generally used is a silicone release liner in which a silicone release agent is coated on the same base material as described above, but in this case, transfer of silicone to the adhesive layer occurs. For this reason, when there is a silicone compound adhering substance on the surface of the measurement sample according to the present invention, analysis becomes extremely difficult if the surface of the pressure-sensitive adhesive to which it is transferred is subjected to surface analysis.

  Therefore, the release liner of the pressure-sensitive adhesive material according to the present invention is a silicone-free release agent, for example, a fluorine-type release agent, a polyolefin-type release agent or the like that does not transfer the release agent to the pressure-sensitive adhesive layer, or a release agent-free base. Use an adhesive with a release liner made of only material. In recent years, these are used for adhesive tapes, levels, and sheets used in hard disks (HDD), semiconductors, and other precision electronic parts / equipment that are particularly resistant to silicone contamination. As a commercial item, the single-sided adhesive tape (brand name: SPAP3025T2) by Nitto Denko Co., Ltd., etc. are mentioned.

  However, an adhesive material may be created by itself instead of a commercial product. In this case, there is a problem in labor and storage, but it can be used in the surface analysis method of the present invention without providing a release liner.

  In the present invention, as a method for transferring the adhered substance on the measurement sample surface to the pressure-sensitive adhesive surface, a cylindrical roller wound with a pressure-sensitive adhesive tape or a material in which a pressure-sensitive adhesive tape is attached to the bottom surface of a column or a prism member is used. Examples of the method include rolling a cylindrical roller on the surface of the measurement sample (just like a roller cleaner) or pressing the bottom surface of a cylinder or a prismatic member several times. Thereby, the adhered substance on the measurement sample surface can be easily transferred to the pressure-sensitive adhesive surface.

  The material of the cylindrical roller, cylinder, or prism is not particularly limited, but stainless steel that is easy to process is suitable. The size of these members is not particularly limited, but it is more effective to transfer the measurement sample surface as wide as possible onto the adhesive surface in the narrowest possible area. It is considered that the width and diameter of the columnar roller are about several mm, and the bottom size of the cylinder or prism is preferably several mm or several mm square. In addition, the method for fixing the adhesive material to these members is not particularly limited, but if the adhesive material is coated with adhesive on both sides, it is sufficient to bond and fix one side to the member as it is, only one side. If a pressure-sensitive adhesive is applied to the material, a transfer adhesive material may be fixed by sticking a general double-sided pressure-sensitive adhesive tape to the member.

  Moreover, as a characteristic of the adhesive layer of the adhesive substrate, it is only necessary to have an adhesive force capable of transferring the adhered substance on the sample surface. As a guideline, 0.5 N / cm (180 ° direction, adherend: SUS) , Tensile speed: 300 mm / min, pressure bonding method: 2 kg roller 1 reciprocation) or more. Furthermore, it is preferable that there is no adhesive residue when pressure-bonded onto the sample surface. Furthermore, when the transferred adhesive surface is subjected to surface analysis, it is placed under a high vacuum, and therefore, it is advantageous that the amount of outgassing of the adhesive base material is small because it can be measured without evacuation.

  As the surface analyzer in the present invention, an XPS (X-ray Photoelectron Spectroscopy) analyzer and a TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) analyzer are preferably used, and other surface analyzers are used. However, for example, in the infrared reflection method, almost no element qualitative analysis information can be obtained, and it is difficult to detect a thin organic layer on the adhesive layer. In addition, in a dynamic secondary ion mass spectrometer (Dynamic SIMS), which is a general SIMS analyzer, the amount of primary ion irradiation is significantly larger than that of TOF-SIMS, and small fragment ions or particles are used when ionizing organic samples. Therefore, the chemical structure information obtained from the mass spectrum is limited and not suitable.

  In addition, the XPS analysis and the TOF-SIMS analysis in the present invention may be performed by one apparatus depending on the measurement object or measurement purpose, or may be performed by using both apparatuses in combination. XPS can be either a non-monochromatic type that does not have an X-ray monochromator or a monochromatic type that has an X-ray monochromator. There are features such as high sensitivity. As a measurement sample, almost all solid samples such as metals, semiconductors, ceramics, and organic compounds can be measured. In addition to elemental information, knowledge about the chemical state can be obtained, and the quantitativeness can be said to be good in surface analysis. However, in XPS, the energy shift of the chemical shift due to the difference in chemical state is small, and there are many cases where data processing such as waveform separation is necessary, and the detailed molecular structure cannot be analyzed. On the other hand, since TOF-SIMS often gives more direct chemical bond information as a fragment peak to a measurement sample similar to XPS, more specific substance identification and molecular structure analysis are possible. However, in TOF-SIMS, mass spectrum analysis is often complicated, and there are problems such as inferior quantitativeness compared to XPS. Therefore, XPS and TOF-SIMS are combined for the analysis of comprehensive surface chemical state. It is effective to use.

  The features of the XPS analysis method and the TOF-SIMS analysis method are all directed to the outermost surface of the sample surface, and the obtained data is limited to the number of surface layers to several tens of nm region. Further, the measurement area (surface resolution) can be said to be an area of several tens to several hundreds of micrometers in XPS (several millimeters are possible with the old model, but detection sensitivity is low) and several to several hundreds of micrometers in TOF-SIMS. Therefore, it is convenient to detect the transfer component on the surface of the pressure-sensitive adhesive layer according to the surface analysis method of the present invention. It is a surface analysis method that allows easy detection by concentrating and collecting a wide area of the surface on an adhesive surface to be measured by transferring with an adhesive material.

  Next, the present invention will be described with reference to specific examples, but the present invention is not limited thereto.

  In the following examples, the XPS analyzer and the TOF-SIMS analyzer used in the surface analysis were used under the following conditions.

(apparatus)
model-1600 (manufactured by ULVAC-PHI)
(Measurement condition)
・ X-ray source: MgKα
・ X-ray output: 250W (15kV)
・ Measurement area: 800μmΦ
(apparatus)
TRIFT-II (PHI / EVANS)
(Measurement condition)
・ Primary ion source: Au1 +
・ Detection: Positive
・ Acceleration voltage: 19kV
・ Measurement area: 200μm
<Example 1>
About the polyethylene film with a bad sealing performance, and the favorable polyethylene film, each sealing surface was measured by XPS. As a result of the measurement, C and O were mainly detected in all cases, and there was not much difference between the defective product and the non-defective product (see Table 1, FIG. 3 and FIG. 4). Therefore, a commercially available adhesive tape (single-sided adhesive tape manufactured by Nitto Denko Co., Ltd .: SPAP3025T2) according to the present invention is wound around a cylindrical roller (5 mm in width) that has been prepared in advance. Rolling was performed on a 15 cm square region, and the deposit on each film was transferred to the adhesive tape surface, and XPS measurement and TOF-SIMS measurement were performed on the adhesive tape surface after transfer. As a result, looking at the XPS measurement results (Table 1), only C and O were confirmed on the adhesive surface before transfer, and Si was detected in addition to C and O from the transferred adhesive surface of defective and good products. In addition, the Si ratio was about twice as high for defective products than for non-defective products. When the Si2p narrow spectrum was observed (FIG. 6), it was inferred from the binding energy value at the peak position as silicate or silicone. Moreover, when the TOF-SIMS measurement spectrum is seen (FIGS. 11-1, 2 and 12-3), the fragment ion peaks derived from silicones of Si + (28) and CH3Si + (43) which are not present on the adhesive surface before transfer are observed. confirmed. Therefore, Si detected by XPS was considered to be derived from silicone.

  From the above, it was inferred that the cause of the poor sealability may be due to a trace amount of silicone on the polyethylene film or non-uniformly adhered silicone.

  Table 1 shows the XPS measurement results examined for defective seals and non-defective films.

<Example 2>
A standard sample was prepared to verify the surface analysis method of the present invention. As a standard sample, a 10 ppm hexane solution of commercially available silicone (polydimethylsiloxane manufactured by SIGMA: trade name DMPS2C-100G) is prepared, and a PET film (thickness 25 μm, 15 cm □) is immersed in the solution. Then, the solution was wiped off and a PET film with a small amount of silicone attached was obtained. Then, when XPS measurement was performed on the original PET film and the prepared PET film (hereinafter, standard sample), only C and O were detected from the original PET film, but a small amount of Si was detected from the standard sample. (See Table 2, FIG. 7, FIG. 8, FIG. 9, FIG. 10). Next, using the commercially available adhesive tape according to the present invention (single-sided adhesive tape manufactured by Nitto Denko Corporation: SPAP3025T2), silicone adhered on the PET film is transferred to the adhesive tape surface in the same manner as in Example 1. The XPS measurement and the TOF-SIMS measurement were performed on the adhesive surface after transfer. As a result, when the XPS measurement result (Table 2) was observed, the Si ratio of the pressure-sensitive adhesive surface to which the standard sample was transferred was detected 5 times higher than that of the standard sample. Moreover, when the TOF-SIMS measurement spectrum of the adhesive surface which transcribe | transferred the standard sample was seen (FIG. 12-4), the fragment ion peak derived from the silicone of Si + (28) and CH3Si + (43) was confirmed.

  Table 2 shows the XPS measurement results examined with the standard sample.

From the above, it was confirmed that the deposits on the measurement sample surface can be concentrated and detected by the surface analysis method of the present invention.

It is the XPS wide spectrum which XPS measured the adhesive surface of the adhesive tape concerning this invention used in Example 1 and Example 2. FIG. It is the XPS narrow spectrum which XPS measured the adhesive surface of the adhesive tape concerning this invention used in Example 1 and Example 2. FIG. It is the XPS wide spectrum which XPS measured the transfer surface (adhesive surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the film surface of the poor seal | sticker product in Example 1, and a good product. It is the narrow spectrum which carried out XPS measurement of the transfer surface (adhesion surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the film surface of the poor seal | sticker product in Example 1, and a good product. It is the XPS wide spectrum which XPS measured the transfer surface (adhesive surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the film surface of the poor seal | sticker product in Example 1, and a good product. It is the XPS narrow spectrum which XPS measured the transfer surface (adhesion surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the film surface of the poor seal | sticker product in Example 1, and a good product. 3 is an XPS wide spectrum obtained by XPS measurement of a PET film surface used for preparing a standard sample in Example 2. It is the XPS narrow spectrum which XPS measured the PET film surface used for standard sample preparation in Example 2. FIG. It is the XPS wide spectrum which XPS measured the transfer surface (adhesive surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the standard sample surface in Example 2, and a standard sample surface. It is the XPS narrow spectrum which XPS measured the transfer surface (adhesive surface) transcribe | transferred with the adhesive tape concerning this invention with respect to the standard sample surface in Example 2, and a standard sample surface. It is a TOF-SIMS measurement spectrum demonstrated in Example 1 and Example 2. FIG. It is a TOF-SIMS measurement spectrum demonstrated in Example 1 and Example 2. FIG. It is the front view of the transfer tool of the cylindrical roller concerning this invention, the member of a cylindrical roller, and the perspective view of an adhesive tape. It is a perspective view of the transfer tool of the cylinder or prismatic member concerning the present invention.

Explanation of symbols

1. Adhesive tape 1a in a state of being wound around a cylindrical roller. 1. Adhesive tape removed from the cylindrical roller Cylindrical roller member (front view)
2a. Cylindrical roller member (perspective view)
3. Pattern 4. Knob part 5. 6. Adhesive tape 6. Cylindrical member Adhesive tape8. Prismatic member

Claims (6)

  A surface analysis method characterized in that a substance adhering to the surface of a sample to be analyzed is transferred to an adhesive surface of an adhesive substrate, and the substance is analyzed by surface analysis of the adhesive surface to which the substance is transferred.   Analyze the substance by collecting a wide range of substances adhering to the surface of the sample to be analyzed, concentrating it on the adhesive surface of the adhesive substrate, transferring it, and analyzing the surface of the adhesive surface to which the substance is transferred at a high concentration. The surface analysis method according to claim 1.   The pressure-sensitive adhesive substrate is composed of a pressure-sensitive adhesive (pressure-sensitive adhesive) having a pressure-sensitive adhesive surface on one side or both sides, and a pressure-sensitive adhesive composition on the pressure-sensitive adhesive surface. 3. The surface analysis method according to claim 1, wherein impurities other than components are not contained.   A peelable substrate is laminated on the pressure-sensitive adhesive surface (pressure-sensitive adhesive) of the pressure-sensitive adhesive substrate, and the peelable substrate does not contain a silicone component as a release agent, or The surface analysis method according to any one of claims 1 to 3, wherein the surface analysis method is a releasable base material that does not contain the release agent itself.   The adhesive substrate is affixed to the bottom surface of a cylindrical roller or cylinder or prism member, and the substance adhered to the sample surface is transferred by rolling or pressing several times on the sample surface to be analyzed. The surface analysis method according to any one of claims 1 to 4, wherein the substance is analyzed by subjecting the transferred adhesive surface to a surface analysis. In the surface analysis method according to any one of claims 1 to 5,
XPS (X-ray Photoelectron Spectroscopy) analyzer and TOF-SIMS (Time-of-Flight Secondary Ion)
A surface analysis method comprising using a mass spectrometer.