JP6519804B2 - Method of analyzing the abnormal part of the surface of the laminate - Google Patents

Description

  The present invention relates to a method of analyzing an abnormal part of the surface of a laminate.

  In recent years, electronic devices have been required to have higher reliability. Therefore, in the manufacturing process, quality control is more important, and its certainty is required. For quality control, for example, it is necessary to identify not only the foreign matter mixed in the final product or the intermediate product but also to identify the cause of the foreign matter mixing. Specifically, it is necessary to specify what kind of component the foreign matter is and from which it originates.

  For example, as a method of analyzing foreign matter (particles) adhering to the wafer surface, after the foreign matter on the wafer is found by observation, the foreign matter is irradiated with a laser beam, and Raman scattered light generated from the foreign matter is generated. A method for analyzing foreign matter has been proposed (see, for example, Patent Document 1).

Unexamined-Japanese-Patent No. 2006-300883

  In quality control, when a part having an abnormal appearance is observed by appearance inspection of a product, it is grasped whether a substance causing the abnormal appearance is present near the surface or present inside. It is important to identify the substance.

  The present invention addresses the above-mentioned quality control requirements, and in the case where an abnormal appearance is observed on the surface of the laminate, the present position of the substance causing the abnormal appearance is grasped, and further, The purpose is to provide a technology to analyze the substance with high accuracy.

The first aspect of the present invention is
A method of analyzing an abnormal part of a surface of a laminate comprising a resin layer and a metal layer laminated on the resin layer,
An abnormal part specifying step of observing the surface of the metal layer and specifying the position of the abnormal part occurring on the surface of the metal layer;
A surface analysis step of acquiring an EDX spectrum and a Raman spectrum corresponding to the surface of the abnormal portion;
A cutting step of cutting the laminate so as to divide the abnormal portion to produce a cut surface;
A method is provided for analyzing an abnormal part of the surface of a laminate, comprising: acquiring a EDX spectrum and a Raman spectrum corresponding to the abnormal part exposed to the cut surface and analyzing the abnormal part. .

According to a second aspect of the present invention, there is provided a method of analyzing an abnormality on a surface of a laminate of the first aspect,
In the cutting step, a focused ion beam is irradiated and cut toward the laminate.

  ADVANTAGE OF THE INVENTION According to this invention, the abnormal part of the surface of the laminated body by which the metal layer was laminated | stacked on the resin layer can be analyzed accurately.

In the method of analyzing the abnormal part of the surface of the layered product of the present invention, it is a figure explaining surface analysis of a layered product. In the method of analyzing the abnormal part of the surface of the layered product of the present invention, it is a figure for explaining section analysis of a layered product. It is a figure which shows an abnormal part when the laminated body of Example 1 is planarly viewed with an optical microscope. It is a figure which shows the cross section in the dotted line in FIG.

<One embodiment of the present invention>
Hereinafter, a method of analyzing an abnormal part according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining surface analysis of a laminate in a method of analyzing an abnormal part of a surface of a laminate according to the present invention. FIG. 2 is a view for explaining cross-sectional analysis of a laminate in the method of analyzing an abnormal part of the surface of the laminate according to the present invention.

  As shown in FIG. 1, the laminate 10 is configured to include a resin layer 11 and a metal layer 12 laminated on the resin layer 11. When the laminate 10 is planarly viewed with an optical microscope and the abnormal portion 13 is observed due to the difference in appearance with the surroundings, is the abnormal portion 13 formed on the metal layer 12 or the resin layer 11 It can not be known just by observing the surface whether it is formed between the metal layer 12 and the metal layer 12.

  Therefore, in the present embodiment, not only the surface analysis but also the cross-sectional analysis is performed on the abnormal portion 13 of the surface of the laminate 10 to analyze the abnormal portion 13 with high accuracy. Specifically, an abnormal part identification step, a surface analysis step, a cutting step, and a cross-sectional analysis step are performed on the laminate 10. Each step will be described in detail below.

(Abnormal part identification process)
In this embodiment, in order to analyze the abnormal portion 13 present on the surface of the laminate 10, first, the surface of the metal layer 12 is observed to specify the position of the abnormal portion 13. Specifically, the surface of the metal layer 12 is observed by, for example, an optical microscope, and the position of the abnormal portion 13 that looks different from the surroundings is specified.

(Surface analysis process)
Subsequently, an EDX spectrum and a Raman spectrum corresponding to the abnormal portion 13 observed on the surface of the metal layer 12 of the laminate 10 are acquired, and the abnormal portion 13 is analyzed. Specifically, an EDX spectrum and a Raman spectrum corresponding to the surface 14 of the abnormal portion 13 (hatched portion in the figure, hereinafter, also referred to as the abnormal portion region 14) are acquired.

  By measuring the abnormal part area 14 by SEM-EDX, it can be grasped what element the abnormal part area 14 is composed of. In SEM-EDX, it is possible to analyze an element to a minute object of several μm order. For example, if the abnormal area 14 is made of an inorganic compound such as a metal or a metal oxide, it is possible to identify the type of the compound by specifying the element of the abnormal area 14. On the other hand, when the abnormal area 14 is made of an organic substance, elemental analysis can be performed such that the abnormal area 14 contains, for example, carbon as an organic substance, but the chemical structure etc. can not be identified, and the type as an organic compound is identified. Can not do it. Therefore, detailed information including the chemical structure and the like is acquired for the anomalous part region 14 by microscopic Raman spectroscopy described later, and the compound species is identified.

  Further, analysis is performed on the abnormal area 14 in order to grasp the chemical structure of the organic matter. As a method of analyzing the chemical structure of the minute abnormal part region 14, spectroscopic methods such as microscopic Raman spectroscopy and microscopic Fourier transform infrared spectroscopy (microscopic FTIR) can be considered, but in the present embodiment, microscopic Raman spectroscopy is used. The abnormal area 14 is identified.

  Micro-Raman spectroscopy is a micro-Raman spectroscopy system that combines an optical microscope and a laser Raman spectrometer. This introduces monochromatic light (laser light) into a microscope, condenses laser light onto a micro sample placed under the microscope, collects scattered light from the micro sample with a microscope, and introduces it to a Raman spectrometer To obtain a Raman spectrum. A method of performing chemical analysis of various compounds with high spatial resolution by detecting and dispersing Raman scattered light generated when a sample is irradiated with a laser beam to obtain information on the chemical bond, crystal state, etc. of the sample. it can. Also, the substance name of the sample can be identified by comparing the Raman spectrum of the measured sample with the database of spectra of known substances.

  In the present embodiment, the reason for analyzing the anomalous part region 14 by microscopic Raman spectroscopy is that the spatial resolution (minimum analysis size) is about 1 μm according to microscopic Raman spectroscopy, and the spatial resolution of microscopic FTIR ( This is because smaller samples smaller than about 10 μm can be analyzed.

  Specifically, the laminate 10 is introduced into the measurement unit of the microscopic Raman spectroscopic analyzer. At this time, lamination is performed so that the abnormal part region 14 of the laminated body 10 is orthogonal to the optical axis of the monochromatic light 30 (laser light 30) irradiated by the measurement part and that the depth of focus is the same on the analysis surface. Place the body 10 in the measuring section.

  Next, the laser beam 30 is irradiated to the abnormal area 14 of the laminate 10 disposed in the measurement unit. The Raman scattered light generated from the abnormal part region 14 by irradiation is dispersed by the spectroscopic part, and the dispersed Raman scattered light is detected by the detecting part to finally obtain the Raman spectrum of the abnormal part region 14. Then, by comparing the Raman spectrum of the anomalous region 14 with the Raman spectrum of the known substance, the compound species of the anomalous region 14 is identified.

  As a result of the surface analysis process, for example, when the EDX spectrum of the abnormal area 14 is the same as that of the metal layer 12 or when a Raman spectrum can not be obtained from the abnormal area 14, the metal layer 12 is present in the abnormal area 14. It is understood that it exists. That is, it can be seen that the abnormal portion 13 is covered with the metal layer 12 and formed between the metal layer 12 and the resin layer 11. Conversely, when the EDX spectrum of the abnormal area 14 is different from that of the metal layer 12, the metal layer 12 does not exist in the abnormal area 14, and the abnormal area 13 is not covered with the metal layer 12. It can be seen that it is formed on top. In this case, the Raman spectrum of the abnormal portion 13 can identify the compound type. In the present embodiment, the EDX spectrum of the abnormal portion region 14 is the same as that of the metal layer 12, and the case where the abnormal portion 13 is formed between the resin layer 11 and the metal layer 12 is exemplified below. .

In the surface analysis step, irradiation conditions of the laser light when performing microscopic Raman spectroscopy are not particularly limited. The irradiation conditions include, for example, a laser wavelength, a laser intensity, an exposure time, etc. These may be appropriately changed in order to obtain a Raman spectrum having a high SN ratio in a short time measurement.
Although the excitation wavelength of the laser light source is not particularly limited, the region 450 to 800 nm of visible light is used for the purpose of suppressing the damage of the abnormal region 14 etc. and obtaining high spatial resolution that can analyze the fine abnormal region 14. Preferably, for example, an argon ion laser or a helium neon laser can be used. The wavelength of the laser light is preferably basically short. The reason is that the shorter the wavelength, the higher the efficiency of Raman scattering.
The laser beam intensity is not particularly limited as long as the abnormal area 14 and the like are not damaged by the laser beam. For example, the laser intensity may be gradually increased from a low level (about 1%) and appropriately adjusted so as to have high sensitivity in a range where the abnormal area 14 and the like are not damaged.
Further, the exposure time may be appropriately changed so that the intensity of the Raman spectrum can be sufficiently obtained with the laser intensity determined above.

(Cutting process)
Subsequently, in order to analyze the abnormal portion 13 formed between the resin layer 11 and the metal layer 12 and which can not be directly analyzed from the surface, the laminate 10 is cut, and the abnormal portion 13 is exposed at the cut surface at the cut surface. To do. Specifically, as shown in FIG. 1, the lamination direction of the laminate 10 along a cut line (dotted line in FIG. 1) where the abnormal part 13 (abnormal part area 14) observed on the surface is divided. Cut into Thereby, as shown in FIG. 2, the cut sample 20 which the abnormal part 13 is exposed to the cut surface 20a is produced. In the cross-sectional analysis process described later, the cut surface 20 a of the cut sample 20 is used as an analysis surface.

  Although it does not specifically limit as a cutting method, According to the thickness of the laminated body 10, and the magnitude | size of the abnormal part 13, it is good to change suitably. If the laminate 10 is thin and the abnormal portion 13 has a size that can be visually confirmed, processing may be performed manually using scissors or the like. If the abnormal portion 13 is fine, it is preferable to cut it using a focused ion beam (FIB). According to FIB, since a SIM (Scanning Ion Microscope) image can be observed by measuring secondary electrons when the laminate 10 is irradiated with an ion beam, cutting is performed while observing the SIM image. Can. In addition, since the resolution is 10 nm or less, the cutting process can be performed even if the abnormal portion 13 has a minute size, for example, a sub-μm level.

(Section analysis process)
Subsequently, an EDX spectrum and a Raman spectrum corresponding to the abnormal portion 13 exposed to the cut surface 20 a are acquired, and the abnormal portion 13 is analyzed.

  The above-described SEM-EDX analyzer acquires an EDX spectrum corresponding to the abnormal portion 13 exposed to the cut surface 20a. Moreover, the Raman spectrum corresponding to the abnormal part 13 exposed to the cut surface 20a is acquired by the micro Raman spectroscopy analyzer mentioned above. The abnormal part 13 is identified based on the acquired information.

  As described above, according to the method of the present embodiment, in the laminate 10 in which the metal layer 12 is laminated on the resin layer 11, when the abnormal portion 13 is observed on the surface on the metal layer 12 side, the abnormal portion 13 is observed. Can be grasped on the surface of the metal layer 12 or between the resin layer 11 and the metal layer 12, and moreover, the abnormal portion 13 can be identified with high accuracy. .

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments in any way, and various modifications can be made without departing from the scope of the present invention.

  Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples.

Example 1
First, a laminate to be analyzed was prepared. In this example, a laminate in which a metal layer was laminated on one side of a resin layer was prepared. The thickness of the resin layer was about 50 μm, and the thickness of the metal layer was 1 μm or less.

  Next, the surface of the metal layer of the prepared laminate was observed with an optical microscope to identify the position of the abnormal portion. The abnormal part is shown in FIG. FIG. 3 is a view showing an abnormal portion when the laminate of Example 1 is planarly viewed by an optical microscope. In the laminate, the abnormal area 14 was observed due to the difference in appearance with the surroundings, and it was confirmed that the abnormal area 14 is rod-like and has a width of about 30 μm.

Subsequently, an EDX spectrum corresponding to the upper surface of the abnormal region was obtained by the SEM-EDX analyzer. As a result, it was found that the abnormal portion was composed of the same component as the metal layer.
A field emission scanning electron microscope JSM-7100F manufactured by JEOL Ltd. was used as the SEM-EDX analyzer. As measurement conditions, the acceleration voltage is 5 kV at the observation time and 15 kV at the analysis time. D (the distance between the analysis sample and the probe) was 10 mm in observation and analysis.

Further, the laminate was placed on the sample stage of the microscopic Raman spectroscopy analyzer. The sample stage was moved immediately below the objective lens of the optical microscope provided in the analyzer. Then, the focal point of the laser light was moved to the upper surface of the abnormal region, and a Raman spectrum corresponding to the upper surface of the abnormal region was obtained. However, the Raman spectrum having an effective peak could not be obtained, probably because the abnormal region is made of metal.
In addition, DXR type manufactured by Thermo Fisher Scientific Co., Ltd. was used as a microscopic Raman spectroscopic analyzer. The measurement conditions are as follows. As the excitation light source, an Ar laser with a wavelength of 532 nm was used. The output of the excitation light was set to be 5 mW on the analysis surface of the analysis sample. The laser light intensity was gradually increased from a low intensity to a high intensity so as not to damage an abnormal part and the like. As an objective lens, a long focus lens with a magnification of 50 was used. The exposure time was 1 second, the number of times of exposure (integration) was 100, the aperture was 25 μm pinhole, the measurement range was 100 cm ^{−1 to} 3400 cm ^−1, and the upper surface of the abnormal area was measured.

  As a result of surface analysis of the laminate, it was found that the abnormal area was made of metal and the abnormal area was formed between the resin layer and the metal layer and covered with the metal layer.

  Subsequently, in the FIB, the laminate was cut so as to divide the abnormal portion (abnormal portion region), and a cut sample in which the abnormal portion was exposed on the cut surface was obtained. The cut surface is shown in FIG. FIG. 4 shows a cross-sectional view in dotted line in FIG. As shown in FIG. 4, it was confirmed that the abnormal portion 13 was present on the resin layer 11 and that the thickness of the abnormal portion 13 was about 25 μm.

Subsequently, an EDX spectrum corresponding to the cut surface of the analysis sample was acquired by the SEM-EDX analyzer. As a result, no metal element was detected from the abnormal part, and it was confirmed that it was an organic substance.
In addition, a metal plate was attached to the side surface of the cut sample, and this was placed on the sample stage of the microscopic Raman spectroscopic analyzer described above. The sample stage was moved immediately below the objective lens of the optical microscope provided in the analyzer. Then, the focal point of the laser light was moved to the cut surface of the abnormal portion, and a Raman spectrum of the abnormal portion of the cut surface was acquired.

  The Raman spectrum obtained from the anomaly is compared with the database of Raman spectra of known substances, and matching Raman spectra are searched. The anomaly is an organic substance having a composition different from that of the resin layer and a different structural formula I understood.

  As described above, according to the present invention, with respect to the abnormal portion on the surface of the laminate in which the metal layer is laminated on the resin layer, the abnormal portion is on the surface of the metal layer or between the resin layer and the metal layer 12 It is possible to determine which of the two is formed, and to analyze the type of the compound. And, according to the present invention, by applying to the manufacturing process of the electronic device etc., for example, when there is an abnormal part on the surface of the intermediate product or the final product, the cause of the generation of the abnormal part is clarified, It can contribute to quality improvement.

DESCRIPTION OF SYMBOLS 10 laminated body 11 resin layer 12 metal layer 13 abnormal part 14 abnormal part area | region 20 cut sample 20a cut surface (analysis surface)

Claims (2)

A method of analyzing an abnormal part of a surface of a laminate comprising a resin layer and a metal layer laminated on the resin layer,
An abnormal part specifying step of observing the surface of the metal layer and specifying the position of the abnormal part occurring on the surface of the metal layer;
A surface analysis step of acquiring an EDX spectrum and a Raman spectrum corresponding to the surface of the abnormal portion;
A cutting step of cutting the laminate so as to divide the abnormal portion to produce a cut surface;
A cross-sectional analysis step of acquiring an EDX spectrum and a Raman spectrum corresponding to the abnormal portion exposed to the cut surface and analyzing the abnormal portion; and analyzing the abnormal portion of the surface of the laminate.   The method according to claim 1, wherein in the cutting step, a focused ion beam is irradiated toward the stack to cut it.