一般財団法人材料科学技術振興財団　MST Product Lineup

This is an introduction to a case study of SCM analysis of commercially available LSI internal MOSFETs. First, the cross-section of a specific transistor is exposed through mechanical polishing. At this time, the Si surface is polished flat to the order of nm. The SCM image allows for the two-dimensional confirmation of layer distribution. While quantitative discussions cannot be made, it is possible to roughly understand the relationship of concentration magnitudes. Additionally, the p/n polarity of the diffusion layer can also be identified. Furthermore, by conducting SEM observations at the same location and performing image synthesis with the SCM analysis results, the positional relationship between the diffusion layer and the upper wiring structure can be clarified.

By using FIB technology that allows for processing at the nanoscale, it is possible to perform planar TEM observations of specific areas. This enables the confirmation of the ONO three-layer structure (silicon oxide film / silicon nitride film / silicon oxide film) of the capacitor insulating film on the sidewall of the hole, which is difficult to verify through cross-sectional observations.

Due to the miniaturization of devices, it is necessary to evaluate the depth distribution of impurities in extremely shallow regions. To perform an accurate evaluation, SIMS analysis using a primary ion beam with lower energy (below 1 keV) is required. In this study, the relative standard deviation of the surface density of B calculated from six measurements conducted over multiple days using a 1 keV oxygen ion beam on Si wafers implanted with B+ at low energy was found to be less than 3%, demonstrating that high reproducibility can be achieved in the evaluation of extremely shallow impurity distributions, similar to conventional SIMS analysis.

In semiconductor device manufacturing, it is necessary to investigate what causes thin deposits that lead to defects in order to examine contamination processes. An analysis was conducted using TOF-SIMS on the deposits for which carbon was detected by EDX and quantified by XPS. When compared to the gloves used for standard samples in each process, similar trends were observed with gloves A and B. Furthermore, verification was performed by adhering the standard sample gloves to silicon wafers. As a result, it was found that they were similar to glove A. Adhering standard samples to silicon wafers for verification is an effective method.

The presence of silanol groups (Si-OH) on the surfaces of glass and wafers affects properties such as hydrophobicity and hydrophilicity. Therefore, it is likely to influence subsequent surface treatments, necessitating control. We will introduce a case where the quantification of silanol groups was performed using TOF-SIMS. To conduct the evaluation, calibration curves were created using several types of samples with different concentrations. In the measurement examples, the silanol groups on the surfaces of samples with different materials and conditions were compared. Measurement method: TOF-SIMS Product fields: LSI, memory, electronic components Analysis purpose: Composition evaluation and identification For more details, please download the materials or contact us.

We compared the states of the Si surface after HF treatment and after ozone treatment. In the positive ion spectrum, the peak intensity of Si was different. The weaker Si intensity after HF treatment is due to Si being metallic, while the stronger Si intensity after UV-ozone cleaning and in the As Received state is due to Si being oxide-based. From the negative ion spectrum, fragment ions reflecting the surface state were detected: SiF, SiH, and Six series after HF treatment, and SiO2 series after UV-ozone cleaning and in the As Received state.

The miniaturization of devices has increased the need for evaluating the depth distribution of impurities in extremely shallow regions. To conduct an accurate assessment, SIMS analysis using a primary ion beam with lower energy (below 1 keV) is required. Figure 1 shows examples of measurements of Si wafers implanted with BF2+ 1 keV, P+ 1 keV, and As+ 1 keV, using a primary ion beam energy of 250 eV to 300 eV.

For membranes with low density, it is difficult to achieve contrast at high acceleration voltages (hundreds of kV) due to the high transmission capability of the electron beam. However, in low acceleration voltage SEM-STEM images, slight differences in density can be reflected, allowing for clear composition contrast. This can be applied to organic EL films, low-k films, gate oxide films, TEOS films, BPSG films, etc., where the differences in density, average mass, and composition are small. 1) STEM observation using SEM equipment with lower acceleration voltage compared to dedicated TEM equipment. Measurement methods: TEM, SEM Product fields: LSI, memory, display, solar cells, lighting Analysis purposes: Shape evaluation, film thickness evaluation For more details, please download the materials or contact us.

Titanium dioxide (TiO2), used in electronic materials, catalytic materials, ultraviolet absorbers, and photocatalysts, exists in two forms with the same composition but different crystal structures: anatase and rutile. We conducted measurements on a polycrystalline TiO2 sample with a thickness of 20 nm, deposited on a Si substrate (Photo 1), using an electron beam probe focused down to approximately 1 nmΦ (FWHM). The EELS spectra obtained from the sample match the standard spectra of anatase TiO2 for both Ti and O (Figures 1 and 2).

By conducting SIMS analysis (SSDP-SIMS) from the substrate side, it is possible to obtain measurements that are not affected by the knock-on effects from the high-concentration layer on the surface due to surface roughness and sputtering. We evaluated the amount of boron penetration from the gate electrode (B-doped Poly-Si) into the substrate. Measurements from the substrate side showed no effects from knock-on, indicating that a more accurate evaluation of the penetration amount is possible. Thus, SSDP-SIMS is effective for assessing the barrier properties of barrier metals, the incorporation of metals into Low-k films, and the evaluation just beneath the rough silicide.

The transparent oxide semiconductor IGZO thin film is being researched and developed as a TFT material for displays. IGZO is a material whose properties change significantly based on the composition of the film, the presence of oxygen vacancies, and crystallinity, making it important to consider the correlation with film quality. We will introduce a case where the crystallinity, film thickness, and film density of three types of IGZO thin films with different heating temperatures were measured and compared using XRD and XRR. It was confirmed non-destructively that crystallization progresses at high temperatures, resulting in higher film density.

When delamination occurs, it is important to identify the components that have worsened the adhesion at the interface. By using a peeling process to physically delaminate at the interface of interest and measuring the components present on that surface with TOF-SIMS, it is possible to investigate the cause of delamination. TOF-SIMS detects secondary ions that are ionized while maintaining the structure of organic materials, allowing us to obtain information about the origin of the components present at the delamination surface, making it effective for investigating the causes of delamination and the process. Measurement methods: TOF-SIMS, peeling, disassembly Product fields: LSI, memory, manufacturing equipment, components Analysis purposes: Evaluation of chemical bonding states, failure analysis, defect analysis For more details, please download the materials or contact us.

Polymeric materials such as polypropylene (PP) react with oxygen and moisture in the atmosphere when heated, causing changes in their molecular structure. Therefore, when foreign substances or contaminants may be present in polymeric materials, it is necessary to use standard materials processed in the same environment as the measurement sample for comparison data. To investigate how the PP standard material changes due to heat treatment (200°C for 30 minutes), FT-IR and TOF-SIMS measurements were conducted.

Polyimide is a material that is used in various fields, including electronic components, due to its high heat resistance and excellent electrical insulation properties. Since surface modification can enhance adhesion to other materials, it is important to understand the state of the modified layer. In this study, TOF-SIMS measurements were conducted under sputtering conditions that minimize the degradation of organic components, allowing for the evaluation of polyimide components in the depth direction. Using GCIB (Ar cluster) for sputtering enables the measurement of the targeted organic components in the depth direction. *GCIB: Gas Cluster Ion Beam

In semiconductor device manufacturing, it is necessary to remove metals remaining on the backside of the wafer from the perspective of improving yield, and it is important to quantitatively understand the amount of metal components remaining. To investigate the concentration distribution of metals remaining on the backside within a range of 500 µm from the bevel area, we conducted evaluations using TOF-SIMS. TOF-SIMS has the spatial resolution to detect metal components only near the bevel area, and by using standard samples with known concentrations, it is possible to quantitatively calculate the concentrations.

We will introduce a case where XRD measurements were conducted by narrowing the X-ray beam to Φ400μm, allowing us to obtain crystal information targeting a specific area rather than the entire surface. In the XRD measurement results of the printed circuit board sample, Cu and BaSO4 were detected at all measurement points (1) to (3), and a peak from Au was detected at the measurement point (1), which is the electrode. This aligns well with the results from XRF measurements. Thus, it is possible to identify crystal structures by targeting regions of several hundred micrometers with different compositions and crystallinities. Measurement methods: XRD, XRF Product fields: LSI, memory, electronic components Analysis purposes: Composition evaluation, identification, structural evaluation For more details, please download the materials or contact us.

In depth-direction analysis of molecular information obtained by TOF-SIMS, (1) the depth resolution is good, (2) it is possible to distinguish the chemical states of inorganic materials such as oxides, nitrides, fluorides, carbides, alloys, and metals, (3) evaluation of trace states is possible, (4) monitoring of OH is possible, (5) relative comparisons between samples (film thickness, composition) are possible, and (6) image analysis allows for a visual capture of the distribution of states at the surface level of a few nanometers. We will summarize the results of natural oxide films and oxide films. Measurement method: TOF-SIMS Product field: LSI, memory Analysis purpose: evaluation of chemical bonding states, evaluation of composition distribution, thickness of corrosion layers For more details, please download the materials or contact us.

The presence of OH and fluoride on the surface of aluminum electrodes is one of the causes of electrode corrosion, and investigating the state of the aluminum surface is essential for identifying the causes of defects. TOF-SIMS excels in depth resolution at the very surface and can measure depth distribution with high sensitivity while monitoring the state of inorganic substances. By evaluating the depth distribution along with OH, we discovered a phenomenon where OH increased without a change in the thickness of the oxide film. In this way, TOF-SIMS enables the evaluation of depth distribution of molecular information of inorganic substances that cannot be obtained through elemental analysis.

We will introduce a case where the thickness of extremely thin films, such as natural oxide films on silicon wafers and silicon nitride thin films, which are less than a few nanometers thick, was calculated using XPS analysis. By measuring the Si2p spectrum of the surface of the Si wafer and performing waveform analysis on the obtained spectrum, we can determine the ratio of the presence of each bonding state, and from this result, it is possible to estimate the film thickness based on the average free path of photoelectrons (Equation 1). XPS allows for non-destructive and simple calculation of thin film thickness on substrates as broad average information.

Typically, SIMS measurements are conducted using chips with a flat surface of a few millimeters in size, but analysis can also be performed on small chips or samples with special shapes, typically less than 1 mm in size, by applying a fixed pre-treatment. Some samples that require investigation of trace components may have shapes that are not suitable for analysis under normal conditions, such as tiny chips or wire-like samples (Figure 1). In such cases, analysis is performed after fixation (Figure 2). Additionally, analysis may be possible for cross-sections, side surfaces, or samples with special shapes by applying pre-treatment.

It is possible to identify the components of foreign substances confirmed by the foreign substance inspection device using a TOF-SIMS installed in a clean room. After evaluating the foreign substances following CMP cleaning, copper and hydrocarbon components were detected from the substances of interest. A wide distribution of the same components was observed around the foreign substances. This suggests that the foreign substance is more likely to be cleaning residue resembling a watermark rather than a particle.

TOF-SIMS has the characteristics of simultaneously evaluating organic and inorganic materials, being capable of analyzing small areas with high sensitivity at the very surface, and allowing evaluation while still in the form of 300mm wafers, making it effective for residue investigations during cleaning processes. We will introduce an analysis case of the removal effect of organic contamination on Si surfaces. TOF-SIMS analysis was conducted on samples where amine-based organic materials were confirmed to be in extremely small quantities by XPS. Even in small areas, it is possible to measure components in such extremely small amounts.

High impact resistance is required for the joints of lead-free solder used in electronic devices such as mobile terminals. To address this issue, solder alloys with trace amounts of elements like Ni have been developed. This document presents a case study comparing the in-plane distribution of a five-component lead-free solder with trace amounts of Ni and Ge added to a Sn-Ag-Cu system, and a three-component solder without additives, using imaging from D-SIMS, which excels in high-sensitivity analysis.

It is possible to determine the concentrations of Si-H and N-H in SiN films through FT-IR analysis. Although it is also possible to determine hydrogen concentration using analyses such as SIMS, this provides the total hydrogen concentration and does not allow for the separate determination of hydrogen bonded to Si and hydrogen bonded to N. In FT-IR, the Si-H stretching vibration and N-H stretching vibration have peaks at different positions, allowing us to use these peaks to determine the respective hydrogen concentrations. Below are examples of analyses that determined the concentrations of Si-H and N-H in SiN films on Si substrates.

In semiconductors, it is possible to determine the ionization potential from the valence band maximum (VBM) and the rising position on the high binding energy side (Ek(min)). Measurements are conducted after Ar ion sputter cleaning to remove surface organic contamination. ■ Determination of the valence band maximum (VBM) The spectrum near the valence band edge is extrapolated linearly to find the intersection with the background. ■ Calculation of the ionization potential Ionization potential (I.P.) = hν - W hν: Energy of the incident ultraviolet light (He I line 21.22 eV) W: Energy width of the spectrum (Ek(min) - VBM)

By conducting EBSD analysis on thinned samples, higher spatial resolution can be achieved compared to conventional bulk samples.

In XPS analysis, in addition to the photoelectron peaks used for evaluation, photoelectron peaks from other orbitals and Auger peaks from X-ray excitation are also detected. Depending on the combination of elements, these sub-peaks can overlap with the target peak and interfere with the evaluation. *Typically, a strong photoelectron peak emitted from an inner shell level close to the outer shell is used. In the quantitative calculations of XPS analysis, the removal of such interfering peaks is primarily performed using the following two methods: 1. Removal using sensitivity coefficient ratios 2. Removal using waveform separation

SR measurement involves diagonally polishing the sample and moving two probes in contact with the sample surface while measuring the electrical resistance directly beneath. The depth from the sample surface at a certain measurement point is determined by the product of the value of Sinθ (bevel angle) when the angle of diagonal polishing of the sample is θ and the distance from the bevel edge to that measurement point. The distance from the bevel edge is calculated as [X-step] × [number of measurement points].

1. Measure the spreading resistance (Ω) directly beneath the surface of the sample that has been polished at an angle by contacting two probes. 2. Create a calibration curve from the measurements of the standard sample and use it to convert the resistance to resistivity (Ω·cm). Additionally, perform distribution corrections as needed through volume correction. *) The calibration curve varies depending on the conductivity type (p-type/n-type) and the surface orientation. 3. Use the relationship between resistivity and carrier concentration*) to calculate the carrier concentration (/cm³).

Imaging SIMS is effective for obtaining spatial distribution information of hydrogen and impurities at ppm levels. By using a RAE (Resistive Anode Encoder) detector for projection-type imaging SIMS, it is possible to obtain distribution images with a larger diameter and deeper regions compared to the commonly used scanning methods in imaging analysis.

Tetramethylammonium hydroxide (TMAH) is used as a developing solution and etching solution in semiconductors. When measuring the concentration of TMAH solution used in Si etching solutions, the large amount of dissolved Si can become an impurity and affect the measurement results. However, evaluation using the IC (ion chromatography) method allows for quantitative analysis of TMAH concentration without being influenced by Si.

Organic acids such as citric acid and malic acid are widely used in various fields, including the semiconductor industry as additives in etching and plating solutions, as well as in food as sour agents and emulsifying stabilizers. In particular, the concentration of organic acids in plating solutions changes over time during use, and this balance affects the quality of the plating, making precise control important. Here, we will introduce a case study of organic acid analysis using IC (ion chromatography).

Copper (Cu), used as wiring material, forms an oxide film in the air. Here, we present a case study evaluating the differences in film thickness due to variations in storage environments. Copper (Cu) wrapped in aluminum foil and copper (Cu) stored in a plastic bag were each kept for 40 days, and the oxide film thickness was measured using TOF-SIMS. Additionally, a continuous investigation over approximately 20 days confirmed reproducibility. TOF-SIMS allows for depth profiling analysis of inorganic materials such as oxides and metals. Measurement method: TOF-SIMS Product fields: Displays, LSI, Memory, Electronic components Analysis purpose: Evaluation of chemical bonding states For more details, please download the materials or contact us.

The surface of copper (Cu) metal exposed to the atmosphere is covered with a natural oxide film, and it is known that such copper surfaces can be broadly classified into the states of "Cu," "Cu2O," "CuO," and "Cu(OH)2." By conducting depth profile analysis of commercially available standard powders of "Cu2O," "CuO," and "Cu(OH)2" using TOF-SIMS, it was found that it is possible to obtain characteristic molecular ions corresponding to each state. Using these molecular ions, it became possible to evaluate the depth profile of the natural oxide film on the surface of metallic Cu. Measurement method: TOF-SIMS. Product fields: Display, LSI, Memory, Electronic components. Analysis purpose: Evaluation of chemical bonding states. For more details, please download the materials or contact us.

- Photoluminescence measurement (PL measurement) can be conducted not only at room temperature but also by placing the sample in a cryostat for low-temperature measurements. Low-temperature measurements tend to show an increase in peak intensity and a decrease in peak full width at half maximum compared to room temperature measurements, which may provide insights into various energy levels. - Below, we will explain the precautions for low-temperature measurements and the differences in spectral shapes between room temperature and low-temperature measurements.

XPS is a surface-sensitive technique, so carbon derived from organic contaminants due to the atmosphere is detected at a significant level. Reducing the influence of this carbon from organic contaminants is important for evaluating the original composition of the film. Typically, Ar ion sputtering is used to remove organic contaminants, but damage caused by sputtering may prevent the evaluation of the film's original composition and bonding states. We present an example where the influence of carbon from organic contaminants was reduced by removing the surface oxide layer using wet etching instead of Ar ion sputtering.

In XPS analysis, the binding state evaluation of the material surface is conducted by observing the energy of photoelectrons obtained through X-ray irradiation. It allows for the assessment of whether metal elements are in an oxidized state, and for elements with significant energy shifts (chemical shifts) due to oxidation, it also enables the evaluation of the presence and proportion of multiple valences. Below are the main metal elements and oxides for which multiple valence evaluations are possible.

ABF-STEM images (scanning transmission annular dark field images) allow for the direct observation of atomic positions of light elements. Simultaneous acquisition with HAADF-STEM images enables more detailed structural analysis. In this case, we present an example of observing atomic columns of strontium titanate (SrTiO3). By combining EDX elemental distribution analysis, we can visually clarify the distribution of atoms. Measurement methods: TEM・EDX Product fields: LSI・Memory Analysis purposes: Shape evaluation・Structural evaluation For more details, please download the materials or contact us.

Pole figure measurement is a method that focuses on specific crystal planes and evaluates the distribution of crystal orientations by directing X-rays from various directions onto the sample. The detector is fixed at the diffraction angle (2θ) of the crystal plane of interest, and the two parameters, α (the tilt angle of the sample) and β (the in-plane rotation angle of the sample), are varied to measure crystal planes tilted in all directions. This indicates that the crystal orientations are concentrated in the directions where high diffraction intensity is observed. Additionally, the measurement results are represented in a pole figure as shown in the diagram at the bottom right.

The electron diffraction method using an electron microscope is classified into three types based on the way the electron beam is incident on the sample. The characteristics of each type and examples of data are presented. It is necessary to choose the appropriate method according to the size of the evaluation object and the analysis purpose.

Nitrogen is utilized in various forms across a wide range of fields including chemistry, materials, food, and pharmaceuticals. Nitrogen compounds consist of inorganic nitrogen compounds such as nitrates, nitrites, and ammonia, as well as organic nitrogen compounds like amino acids. In the case of samples in aqueous solution, inorganic nitrogen compounds such as nitrate ions, nitrite ions, and ammonium ions can be evaluated using ion chromatography, while organic nitrogen can be assessed using HPLC or LC/MS. Total nitrogen, which includes both inorganic and organic nitrogen compounds, can be evaluated using spectrophotometry.

Knowledge about the effects of contamination and oxidation during sample transport is important in surface analysis where the detection depth is on the nanometer order. Therefore, we examined the impact of contamination and oxidation due to differences in storage methods on Si wafers. In storage with wrapping paper and aluminum foil, there is a tendency for the peaks of organic materials caused by secondary contamination to be weaker. When samples are wrapped and stored in the matte side of aluminum foil during storage and transport, it can suppress contamination and oxidation compared to other storage methods.

To investigate the delamination issue that occurred on the nickel plating over bronze, TOF-SIMS analysis was conducted. By forcibly delaminating the affected area and performing qualitative analysis with TOF-SIMS, siloxanes and potassium compounds (such as potassium chloride and potassium sulfate) were detected from the delamination surface. These components are believed to be the cause of the delamination.

In the quantitative and compositional evaluation of impurities in the semiconductor material SiGe using SIMS, the following considerations must be taken into account during analysis: ● If appropriate quantification corrections are not made according to the Ge concentration, the impurity quantification values may differ by more than 50% from the actual values. Standard samples corresponding to each composition are necessary for quantitative evaluation. ● It is known that the sputtering rates differ between Si and SiGe. In samples where the composition varies with depth, the sputtering rate changes with depth as well. At MST, high-precision compositional analysis is possible through the preparation of standard samples. Additionally, by using calibration curves, impurity analysis and sputtering rate corrections for each composition of SiGe can be performed.

If you want to qualitatively evaluate metallic foreign substances, analyzing only the very surface may result in information about the oxide film present on the surface of the foreign substance, and you may not obtain information about the foreign substance itself. By performing depth analysis using TOF-SIMS, it is possible to evaluate the composition and state of the foreign substance located deeper than the oxide film. This document presents case studies evaluating the state of three locations that are believed to contain aluminum-based foreign substances.