JP5046860B2 - Sample analysis method, analysis sample preparation method, analysis sample, SIMS analysis sample preparation method - Google Patents

Description

  The present invention relates to a method for preparing an analytical sample. In particular, the present invention relates to a method for preparing a SIMS analysis sample.

  When manufacturing industrial products such as semiconductor devices, it is important to understand the concentration distribution of elements in the depth direction. For example, in a semiconductor element such as a field effect transistor (hereinafter referred to as an FET) or a thin film transistor (Thin Film Transistor; hereinafter referred to as a TFT) which is a kind of FET mounted on a semiconductor device, a semiconductor layer is used. From the distribution of the impurity concentration in the impurity region, it can be determined whether or not the conditions for introducing the impurity are appropriate.

  As a typical analysis method for clarifying the concentration distribution in the depth direction, secondary ion mass spectrometry (hereinafter referred to as SIMS), Auger Electron Spectroscopy (hereinafter referred to as AES). And X-ray photoelectron spectroscopy (hereinafter referred to as XPS) method. Since these analysis methods differ in detection sensitivity, element discrimination ability, etc., any analysis method is selected according to the purpose. The SIMS method is a particularly excellent analysis method with respect to detection sensitivity and element discrimination ability.

  In the SIMS method, the surface of the solid sample is sputtered by irradiating the solid sample to be analyzed with the primary ions, and thereby the secondary ions released from the surface of the solid sample are ionized molecules and atoms. This is an analysis method for detection by a mass spectrometer. By using the SIMS method, for example, a thin film is formed on one main surface of a substrate like a TFT formed on an insulating substrate, and an impurity element is introduced into the thin film by an ion implantation method or the like. The concentration of the impurity element can be analyzed. However, when analyzing such a solid sample, when the primary ions are irradiated from the surface side of the thin film, the thin film is sputtered by the primary ions, craters are formed, and the surface shape changes with time. Due to the shape effect (crater edge effect) caused by the surface shape change with time, secondary ions from the crater side wall are detected, and the accuracy of data in the depth direction decreases. Therefore, in order to accurately analyze the dose of the impurity element imparting one conductivity type in the thin film of the solid sample, the back surface of the solid sample is not from the front surface (surface on which the thin film is provided) side of the solid sample. It is preferable to analyze by irradiating with primary ions from the (surface where no thin film is provided) side. In order to analyze in this way, the surface of the uppermost layer of the analysis sample is fixed to a polishing base, and the substrate is polished from the back side by a chemical mechanical polishing (hereinafter referred to as CMP) method or the like. After thinly processing to about 1 μm, SIMS analysis may be performed by irradiating primary ions from the back side of the substrate.

  When performing SIMS analysis, it is usually necessary to have a structure that is not affected by charge-up. Therefore, it is necessary to dispose a material (for example, a silicon wafer) that does not charge up under the film to be analyzed so that the film to be analyzed does not have a floating potential. However, even if an insulating substrate such as a glass substrate does not cause excessive charge-up, a neutralizing gun (for example, an electron gun) provided for electrical neutralization can be used. Analysis becomes possible.

  For polishing the back side of the substrate, a polishing apparatus such as a CMP apparatus is used. The CMP apparatus includes a polishing pad, a holding head (a head for fixing a sample), and a slurry (including polishing powder when mechanically polished). The processing conditions at the time of polishing include load (force in the direction perpendicular to the polishing surface (contact surface between the polishing pad and the holding head)), rotational speed, type of slurry, etc., but these conditions are not easy to set. Absent. For example, it is difficult to polish while maintaining flatness until the thickness reaches about 1 μm, and it can be said that a skill supported by abundant experience is required. In addition, the more time is required to perform polishing carefully by reducing the polishing amount per unit time.

As described above, the method of polishing the back side of the substrate and irradiating the polished surface with primary ions to perform SIMS analysis takes time and effort for polishing. Takes a lot of time. Moreover, high skill is required for the polishing process. Furthermore, the flatness of the substrate is impaired due to the influence of the polishing process of the CMP technique described above, which may cause a problem in accuracy during SIMS analysis (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-210885

  As described above, in the method of polishing the back side of the substrate and irradiating the polished surface with primary ions to perform SIMS analysis, the substrate is polished by CMP technology or the like, and therefore, it takes a lot of time to process the analysis sample. become. Further, in order to perform polishing while maintaining the uniformity and flatness of the analysis sample, skilled skills are required for setting conditions during polishing. As described above, the method of polishing the back side of the substrate and irradiating the polished surface with primary ions to perform SIMS analysis enables more accurate analysis than the normal SIMS analysis method performed by irradiating the front side with primary ions. However, there is a problem that the preparation of the analysis sample is not easy.

  Therefore, the present invention provides an analytical sample preparation method and SIMS analysis method that can be performed more easily and accurately than in the past.

  In one embodiment of the present invention, a thin film or a thin film stack to be analyzed is formed on a substrate, a support is attached to the outermost surface of the thin film or the uppermost layer of the thin film stack, and the thin film or the thin film stack is formed. An analytical sample manufacturing method is characterized by peeling from a substrate.

  In another embodiment of the present invention, a release layer is formed on a substrate, a thin film or a thin film laminate to be analyzed is formed on the release layer, and a support is provided on the outermost surface of the thin film or the uppermost layer of the thin film laminate. Is attached, and the thin film or the thin film laminate is peeled from the peeling layer.

  Another embodiment of the present invention is a method for preparing a sample to be analyzed by secondary ion mass spectrometry, in which a release layer is formed on a substrate, a thin film or a thin film laminate to be analyzed is formed on the release layer, A method for preparing an analytical sample, comprising attaching a support to the outermost surface of a thin film or the uppermost layer of a thin film laminate, and peeling the thin film or thin film laminate from a release layer.

  In the present invention having the above-described structure, a relaxation layer is formed between the peeling layer and the thin film or thin film laminate to be analyzed.

  In the present invention having the above structure, it is preferable to form a film having a higher fluorine concentration than the relaxing layer in the release layer.

In the present invention having the above structure, the release layer and the relaxation layer have a fluorine concentration of 1 × 10 ¹⁷ atoms / cm ³ or more and 2 × 10 ¹⁹ atoms / cm ³ or less, and a hydrogen concentration of 1 × 10 ²¹ atoms / cm ³ or more. 1 × 10 ²² atoms / cm ³ or less, a carbon concentration of 1 × 10 ¹⁵ atoms / cm ³ or more and 2 × 10 ¹⁸ atoms / cm ³ or less, and a nitrogen concentration of 1 × 10 ¹⁸ atoms / cm ³ or more and 1 × It is preferable to form a film with 10 ²⁰ atoms / cm ³ or less and an oxygen concentration of 1 × 10 ¹⁵ atoms / cm ³ or more and 1 × 10 ¹⁹ atoms / cm ³ or less.

  In this invention of the said structure, a support body has an adhesive material provided in the one main surface of the base material and the base material, and it is preferable that an adhesive material consists of a silicone type adhesive agent.

  In the present invention having the above structure, an amorphous silicon film containing fluorine is preferably formed as the peeling layer.

  The silicone adhesive is an adhesive mainly composed of organopolysiloxane. Since silicone is composed of Si—O bonds, it is close to an inorganic polymer, but exhibits the behavior of an organic polymer due to the presence of an organic group (such as a methyl group or a phenyl group) bonded to Si.

  By using the present invention, it is possible to analyze the concentration distribution in the depth direction of the analysis object with high accuracy without using a complicated method.

  In addition, by using the present invention, it is not necessary to perform a polishing step such as CMP unlike the SIMS analysis method in which the back surface side of the substrate is polished and the polished surface is irradiated with primary ions. Therefore, in the method of polishing the back side of the substrate and irradiating the polished surface with primary ions to perform SIMS analysis, it is possible to reduce the time and cost spent for polishing. Since time is not spent for polishing, the concentration distribution in the depth direction can be analyzed in a shorter time than before.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes, and those skilled in the art can easily understand that the modes and details can be variously changed without departing from the spirit and scope of the present invention. Is done. Therefore, the present invention is not construed as being limited to the description of this embodiment mode.

  FIG. 1 is a cross-sectional view schematically showing one embodiment of an analytical sample produced by applying the present invention. The analysis sample in FIG. 1 includes a support 101, a thin film stack 102, a relaxation layer 103, and a release layer 104.

  Next, an example of a method for producing the analysis sample illustrated in FIG. 1 will be described with reference to FIG.

  First, the separation layer 104, the relaxation layer 103, and the thin film stack 102 are sequentially stacked over the substrate 105 (see FIG. 2A).

  As the substrate 105, a mirror-polished silicon wafer or a glass substrate is used. As the glass substrate, quartz glass or low-melting glass may be used. The heat resistance temperature of the low melting point glass is about 700 ° C. When a glass substrate is used as the substrate 105, a film deposited on a large glass substrate as used in a flat panel display typified by a liquid crystal display device or an EL display device can be evaluated.

The peeling layer 104 is not limited to a specific material as long as it does not become a contamination source in the analyzer. For example, a semiconductor material such as silicon (Si) or a conductive material such as tungsten (W), molybdenum (Mo), titanium (Ti), or tantalum (Ta) may be used. A silicon film is preferably used as the peeling layer 104. More preferably, a silicon film containing fluorine (F) is used. By forming the peeling layer using a silicon film containing fluorine, peeling is facilitated. As such a silicon film containing fluorine, specifically, a silicon film containing fluorine (F) of 1.0 × 10 ¹⁷ atoms / cm ³ or more and 2.0 × 10 ¹⁹ atoms / cm ³ or less is preferably used. . More preferably, fluorine (F) is 1.0 × 10 ¹⁷ atoms / cm ³ or more and 2.0 × 10 ¹⁹ atoms / cm ³ or less, and hydrogen (H) is 1.0 × 10 ²¹ atoms / cm ³ or more. 0 × 10 ²² atoms / cm ³ or less, carbon (C) 1.0 × 10 ¹⁵ atoms / cm ³ or more and 2.0 × 10 ¹⁸ atoms / cm ³ or less, nitrogen (N) 1.0 × 10 ¹⁸ atoms A silicon film containing / cm ³ or more and 1.0 × 10 ²⁰ atoms / cm ³ or less and oxygen is 1.0 × 10 ¹⁵ atoms / cm ³ or more and 1.0 × 10 ¹⁹ atoms / cm ³ or less is used. By setting it to such a concentration range, peeling becomes easy. Note that in the case where a film containing a metal element or an organic substance is formed as the peeling layer 104, a layer that does not cause a contamination in an analysis apparatus or a CVD apparatus or a layer that has a low possibility of contamination is used.

  The relaxation layer 103 is formed in order to relieve the physical force applied when the thin film stack 102 formed above the release layer 104 is released. The relaxation layer 103 can be formed under the same film formation conditions as the peeling layer 104, but may be formed under different film formation conditions. Further, the relaxing layer 103 only needs to have a film quality and a film thickness for relaxing a physical force when the thin film laminate 102 is peeled off. For example, it is preferable to form a silicon film having a lower fluorine concentration than the peeling layer 104 as the relaxing layer 103 because the peeling layer peels off the silicon film. Furthermore, it is preferable because physical force can be more effectively relaxed in the relaxation layer.

  Here, a method for manufacturing the separation layer 104 and the relaxation layer 103 using a plasma CVD method will be described. FIG. 3 shows an example of the configuration of a capacitively coupled plasma CVD apparatus. A capacitively coupled plasma CVD apparatus 200 shown in FIG. 3 includes a processing chamber 212 having a substrate electrode plate 202, a high frequency electrode plate 204, a gas introduction unit 206, and an exhaust port 208. Note that although the capacitively coupled plasma CVD apparatus 200 illustrated in FIG. 3 has a form having four exhaust ports, the present invention is not limited to this. The exhaust port 208A, the exhaust port 208B, the exhaust port 208C, and the exhaust port 208D are collectively referred to as the exhaust port 208. The exhaust port 208 is connected to a vacuum pump. Here, a mechanical booster pump (MBP shown in FIG. 3) is connected to the exhaust port 208, the mechanical booster pump is connected to a dry pump (DP shown in FIG. 3), and exhaust is performed from the dry pump. The substrate electrode plate 202 and the high frequency electrode plate 204 are arranged in parallel. The substrate electrode plate 202 and the high frequency electrode plate 204 are connected to an AC power source 210, and the substrate electrode plate 202 is grounded. Note that the impedance of the capacitively coupled plasma CVD apparatus 200 is adjusted by a matching box. The object to be processed (corresponding to the substrate 105 in FIG. 3) is held by the substrate electrode plate 202. The capacitively coupled plasma CVD apparatus 200 is discharged by an alternating current power source 210 to generate plasma between the substrate electrode plate 202 and the high frequency electrode plate 204.

The processing chamber of the plasma CVD apparatus as shown in FIG. 3 is cleaned with a fluorine-based gas. For example, nitrogen trifluoride (NF ₃ ) gas is introduced into the processing chamber 212 from the gas introduction unit 206 at a flow rate of 100 SCCM and argon (Ar) gas at a flow rate of 50 SCCM, and the substrate temperature is set to 300 ° C. under a pressure of 13 Pa. Etching may be performed by setting the output of the 27 MHz RF oscillator to 300 W. After cleaning the inside of the processing chamber 212, a peeling layer made of a silicon film having a high fluorine concentration is formed by an auto-doping method using fluorine 214 remaining in the processing chamber 212, and a silicon film is continuously deposited as it is. Thereby, the relaxation layer 103 made of a silicon film having a low fluorine concentration can be formed on the peeling layer 104. For example, a monosilane (SiH ₄ ) gas is introduced from the gas introduction unit 206 into the processing chamber 212 at a flow rate of 100 SCCM, the substrate temperature is set to 300 ° C., the output of the 27 MHz RF oscillator is set to 170 W under a pressure of 33 Pa, and the film A silicon film having a thickness of about 500 nm is formed. In the silicon film formed at this time, the fluorine concentration in the lower layer on the substrate side is higher than the fluorine concentration in the upper layer. Therefore, the lower silicon film having a higher fluorine concentration becomes a release layer, and the upper silicon film having a lower fluorine concentration. Becomes a relaxation layer. The formed silicon film has a peeling layer with a thickness of about 50 nm and a relaxation layer with a thickness of about 500 nm.

  The thin film stack 102 may be formed by laminating an arbitrary thin film to be analyzed as a single layer or a stacked layer. For example, a semiconductor film containing silicon, an inorganic insulating film such as an oxide film or a nitride film containing silicon oxide, silicon nitride, silicon oxynitride, silicon nitride oxide, or the like is formed. Note that in this specification, even when a thin film to be analyzed has a single-layer structure, it is referred to as a thin film stack for convenience.

  Note that in this specification, silicon oxynitride is a substance in which the oxygen composition ratio is higher than the nitrogen composition ratio, and can also be referred to as silicon oxide containing nitrogen. Similarly, silicon nitride oxide is a substance in which the nitrogen composition ratio is higher than the oxygen composition ratio, and can also be referred to as silicon nitride containing oxygen.

  Moreover, as shown in FIG. 4, you may form so that the lower layer of the film | membrane used as analysis object may serve as a relaxation layer. In the analysis sample illustrated in FIG. 4A, a separation layer 306 is formed over a substrate 308, and a film 304 to be analyzed is formed over the separation layer 306. The lower layer of the film 304 to be analyzed functions as a relaxation layer. For example, a silicon film is formed as the film 304 to be analyzed, and an impurity element is doped into the film 304 to be analyzed by an ion implantation method to form a doped region 310 (see FIG. 4B). By sticking and peeling the adhesive support 302 (see FIG. 4C), the depth of the impurity element doped into the silicon film can be detected at the time of impurity element doping. Furthermore, by using the present invention, since the back surface side of the substrate is polished and the primary surface is irradiated with primary ions and the substrate information detected by the SIMS analysis method is not detected, the influence of the crater edge effect is also affected. Thus, the dose amount of the impurity element can be accurately evaluated.

  Next, an opening 106 is formed in the separation layer 104, the relaxation layer 103, and the thin film stack 102 which are stacked over the substrate 105 (see FIG. 2B).

  In addition, what is necessary is just to form the opening part 106, for example using a physical means (a blade, such as a cutter, or laser irradiation). By forming the opening 106 in the peeling layer 104, the relaxation layer 103, and the thin film stack 102, the thin film stack 102 serving as the analysis sample is easily peeled off when peeled from the substrate.

  Next, the adhesive surface of the support 101 is bonded to the uppermost surface of the thin film laminate 102. The support 101 is attached so as to cover part or all of the opening 106 (see FIG. 2C).

  The support 101 is made of a material that has high heat resistance and is not contaminated to an extent that affects the analysis result in a SIMS analyzer that is maintained at a high vacuum or ultra-high vacuum. In the analysis by the SIMS method, a neutralization gun (for example, an electron) that irradiates a charge having a polarity opposite to the charged charge in order to prevent charging (charge-up) due to irradiation of primary ions to the analysis sample during measurement. The electron gun may irradiate charges. At this time, the analysis sample may be heated due to the influence of the irradiation of the neutralizing gun, and the temperature may rise. Therefore, the heat resistance of the support 101 refers to a degree that can withstand this temperature rise. In addition, since the analysis sample may be heated during the analysis due to the influence of the neutralizing gun or the like as described above, there is no contamination that affects the analysis result in consideration of the temperature increase due to this heating. It is necessary to select a support 101 having an adhesive material on one side. As the support 101, polyimide or Kapton (registered trademark) film or the like can be used as a base material, and a silicone-based adhesive can be used as an adhesive material. Preferably, Kapton (registered trademark) tape is used.

  FIG. 5 shows a top view of FIG. FIG. 2C corresponds to a cross-sectional view of the line segment OP in FIG. In FIG. 5, a relaxation layer 103, a release layer 104, and a substrate 105 are provided below the thin film stack 102 as shown in FIG. An opening 106 is provided in the thin film stack 102, and the support 101 is bonded so as to cover the opening 106. As shown in FIG. 5A, the support 101 need not be provided over the entire surface of the thin film stack 102 and the opening 106, but as shown in FIG. You may bond a support body so that the whole may be covered. Preferably, as shown in FIG. 5A, the support 101 is bonded so that the support 101 does not cover the entire opening 106 and both ends of the opening 106 are exposed. As shown in FIG. 5A, the support can be attached to be peeled off smoothly.

  Next, the separation layer 104, the relaxation layer 103, the thin film stack 102, and the support 101 are separated from the substrate 105 (see FIG. 2D). As described above, an analysis sample including a laminate having the peeled release layer 104, the relaxation layer 103, the thin film laminate 102, and the support 101 is obtained.

  Note that when the analysis sample is peeled from the substrate 105, the support 101 is peeled off using the opening 106 formed in advance as a boundary, and the peeling is performed without going through a complicated process at the boundary between the peeling layer 104 and the substrate 105. can do. The peeling layer 104, the relaxation layer 103, and the thin film stack 102 formed on the substrate 105 are transferred to the support 101 after the peeling step. Note that since the analysis sample is peeled off with the peeling layer 104 as a boundary, the peeling layer 104 transferred to the support 101 after the peeling step may be partially thinned.

  As described above, an analysis sample including a stacked body of the support body 101, the thin film stack body 102, the relaxation layer 103, and the release layer 104 can be manufactured.

  Next, a method for analyzing an analysis sample produced by applying the present invention will be described. FIG. 6 shows a schematic diagram of SIMS analysis. In the schematic diagram of the SIMS analysis shown in FIG. 6, the SIMS analyzer includes an ion source 401, a detector 402, and a neutralizing gun 403. The surface of the analysis sample 404 is sputtered by the primary ions 405 irradiated from the ion source 401, and secondary ions 406 are generated from the surface of the analysis sample. By detecting the secondary ions 406 by the detector 402, the analysis sample 404 produced by applying the present invention can be analyzed.

The ion source 401 is configured to generate cesium ions (Cs ⁺ ) by heating a tank containing solid cesium with a heater. The cesium ion (Cs ⁺ ) that is the primary ion 405 is electrically accelerated and collides with the analysis sample 404 to generate secondary ions 406. The secondary ions 406 are composed of many neutral particles, a small amount of cations, and a small amount of anions. When elements generally called atmospheric components such as hydrogen, carbon, nitrogen, oxygen, and fluorine are included, an anion is introduced to the detector 402, and the analysis sample is detected by the quadrupole mass analyzer of the detector 402. A trace amount of impurities contained in 404 is detected.

  The neutralization gun 403 is an electron gun for preventing the analysis sample 404 from being charged up and being electrically neutralized by irradiation with the primary ions 405. A charge having a polarity opposite to the charge to be charged is irradiated so as to cover the irradiated region of the primary ions 405 on the surface of the analysis sample 404. By using the neutralizing gun 403, it is possible to prevent the analysis sample 404 from being charged up. Further, even when the analysis sample 404 is an insulating material such as a glass substrate or an organic substance (tape or the like), the occurrence of charge-up can be prevented and the secondary ions 406 can be stably generated.

  The analysis sample 404 has a stacked structure in which the peeling layer 104, the relaxation layer 103, and the thin film stack 102 are stacked on the support 101. As shown in FIG. 6, the primary ions 405 are irradiated on the release layer 104 and sputtered, and secondary ions 406 are detected. That is, in the analysis sample 404, the composition in the film is analyzed in order from the release layer 104. Since the release layer is much thinner than the substrate, it is so small that the influence of the crater edge effect and the like can be almost ignored.

  As described above, by using the present invention, primary ions can be irradiated from the back side of a sample without polishing the substrate. Therefore, the impurity concentration analysis can be performed with high accuracy without going through a complicated process. That is, the analysis in the depth direction of the impurities can be performed with high accuracy without performing the substrate polishing step.

  Further, by using the present invention, even when a high concentration of impurities is distributed on the surface of the uppermost layer of the thin film, for example, when the thin film is doped with ions by ion doping using an ion implantation apparatus, the lower layer of the thin film Impurity analysis can be accurately performed from a region where impurities are distributed at a low concentration.

  The result of analyzing the concentration distribution in the depth direction by the SIMS method by applying the present invention will be described.

  FIG. 7 shows a result (profile) obtained by analyzing a sample A produced by applying the present invention by the SIMS method. Sample A has the same configuration as analysis sample 404 described in the embodiment, and is a thin film laminate, relaxation layer, and peeling layer to be analyzed on Kapton (registered trademark) tape used as a support having adhesiveness. The layers were sequentially stacked. For sample A, SIMS analysis was performed by irradiating primary ions from the release layer 104 side. The sample A was brought into close contact with the stage and securely fixed so that the sample A was not deformed by the influence of heat generated by the neutralizing gun (electron gun).

  In this embodiment, the Kapton (registered trademark) tape is a tape using a Kapton (registered trademark) film as a base material and a silicone adhesive as an adhesive material. For example, when soldering a printed circuit board , Used as masking.

  FIG. 8 shows the result (profile) of SIMS analysis of Sample B as a comparative example. Sample B has the same structure as the stacked structure shown in FIG. 2A described in Embodiment 1, and a peeling layer, a relaxation layer, and a thin film stack are sequentially stacked over a glass substrate. For sample B, SIMS analysis was performed by irradiating primary ions from the thin film laminate side (the surface side of the uppermost layer). Note that Sample A had a structure in which an adhesive support was bonded to a thin film laminate manufactured in the same process as Sample B and transferred. Therefore, in Sample A and Sample B, the release layer, the relaxation layer, and the thin film stack are formed of the same layer.

  In SIMS analysis of Sample A and Sample B, the measurement elements were silicon, hydrogen, carbon, nitrogen, oxygen, and fluorine. 8 and 7, silicon is described as Si, hydrogen is described as H, carbon is described as C, nitrogen is described as N, oxygen is described as O, and fluorine is described as F. . 8 and 7, the horizontal axis indicates the depth from the irradiated surface of the primary ions, and the vertical axis indicates the ion intensity.

In FIG. 8, the ionic strength of silicon is stable at about 5 × 10 ⁴ counts / second.

In FIG. 7, the ionic strength of silicon is stable at about 8 × 10 ⁴ counts / second, and is stable at the same ionic strength as in FIG.

  By comparing FIG. 7 with FIG. 8, even when the present invention is applied (FIG. 7 showing the case of peeling), the case where the present invention is not applied (FIG. 8 showing the case of not peeling). It can be seen that the analysis can be performed in the same manner as in FIG.

  In analyzing the concentration distribution in the depth direction by the SIMS method, a result of comparing a sample peeled using the present invention with a sample not subjected to peeling will be described.

The result of analyzing a silicon film doped with boron (B) as an impurity element is shown. FIG. 9 shows a result (profile) obtained by analyzing the sample C manufactured by applying the present invention by the SIMS method. The sample C has the same configuration as the analysis sample 404 described in the embodiment, and a thin film laminate to be analyzed and silicon as a relaxation layer on a Kapton (registered trademark) tape used as an adhesive support. A silicon film containing fluorine is sequentially stacked as a film and a peeling layer, and boron (B) is doped into the silicon film formed as the thin film stack and the relaxation layer. For sample C, SIMS analysis was performed by irradiating cesium (Cs ⁺ ) as primary ions from the release layer side. In Sample C, Sample C was brought into close contact with the stage and securely fixed so that Sample C was not deformed by the influence of heat generated by the neutralization gun (electron gun).

  In this embodiment, the Kapton (registered trademark) tape is a tape using a Kapton (registered trademark) film as a base material and a silicone adhesive as an adhesive material. For example, when soldering a printed circuit board, , Used as masking.

FIG. 10 shows the result (profile) of SIMS analysis of sample D as a comparative example. Sample D has a structure similar to that of the stacked structure in FIG. 2A described in the embodiment, and has a structure in which a peeling layer, a relaxation layer, and a thin film stack are sequentially stacked over a glass substrate. In Sample D, SIMS analysis was performed by irradiating cesium (Cs ⁺ ) as primary ions from the thin film stack side (upper surface side). Note that Sample C had a structure in which an adhesive support was bonded to a thin film laminate manufactured in the same process as Sample D and transferred. Therefore, for sample C and sample D, the release layer, the relaxation layer, and the thin film stack are formed of the same layer. Both Sample C and Sample D were analyzed with a primary ion acceleration voltage of 3 kV and a current density of 100 nA.

In SIMS analysis of sample C and sample D, the measurement elements were boron, silicon, and fluorine. 9 and 10, boron is described as B, silicon is described as Si, and fluorine is described as F. As for boron, both ¹¹ B and its isotope ¹⁰ B were detected. In FIGS. 9 and 10, the horizontal axis represents the depth of the primary ion from the irradiated surface, and the vertical axis represents the ion intensity.

  Comparing FIG. 9 and FIG. 10, in FIG. 10, the ionic strength gradually changes at the boundary between the silicon film and the boron-doped silicon film. On the other hand, in FIG. 9, the ion intensity changes rapidly at the boundary, and the position of the boundary is clear.

Furthermore, FIG. 11 and FIG. 12 show SIMS analysis results (profiles) of boron (B) when O ₂ is used as the primary ion irradiated to the sample C and the sample D. In FIG. 12, as in FIG. 10, the boron concentration changes gently at the boundary between the silicon film and the boron-doped silicon film. In FIG. 11, as in FIG. 9, the concentration of boron changes rapidly at the boundary, and the position of the boundary is clear.

  From comparison between FIG. 9 and FIG. 10 and comparison between FIG. 11 and FIG. 12, sample D is analyzed from the thin film laminate side, so the surrounding boron element is detected by the crater edge effect, and the silicon film and boron dope are detected. It is considered that the position of the boundary of the formed silicon film is unclear. On the other hand, since the sample C to which the present invention is applied is analyzed from the peeling layer side, the analysis is performed with the same accuracy as the SIMS analysis method by polishing the back side of the substrate and irradiating the polished surface with primary ions. It is considered that the position of the boundary between the silicon film and the boron-doped silicon film is clear in the analysis result data.

  By applying the present invention as described above, a SIMS analysis sample can be easily produced, and accuracy is the same as in the SIMS analysis method by polishing the back side of the substrate and irradiating the polished surface with primary ions. It is possible to perform SIMS analysis well. That is, the concentration distribution in the depth direction can be analyzed more accurately.

The conceptual diagram of the analytical sample produced by applying this invention. The figure explaining the process of producing an analysis sample by applying this invention. 1 is a conceptual diagram of a capacitively coupled plasma CVD apparatus when a silicon film is formed by applying the present invention. The conceptual diagram of the analytical sample produced by applying this invention. The figure explaining the process of producing an analysis sample by applying this invention. The conceptual diagram of SIMS analysis about the analytical sample produced by applying this invention. The result of SIMS analysis to which the present invention is applied. The result of SIMS analysis of a conventional analysis sample. The result of carrying out SIMS analysis of the analytical sample produced by applying the present invention. The result of SIMS analysis of a conventional analysis sample. The result of carrying out SIMS analysis of the analytical sample produced by applying the present invention. The result of SIMS analysis of a conventional analysis sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Support body 102 Thin film laminated body 103 Relaxation layer 104 Release layer 105 Substrate 106 Opening part 200 Capacitive coupling type plasma CVD apparatus 202 Substrate electrode plate 204 High frequency electrode plate 206 Gas introduction part 208 Exhaust port 208A Exhaust port 208B Exhaust port 208C Exhaust port 208D Exhaust port 210 AC power supply 212 Processing chamber 214 Residual fluorine 302 Support 304 Analysis target film 306 Release layer 308 Substrate 310 Doped region 401 Ion source 402 Detector 403 Neutralizing gun 404 Analytical sample 405 Primary ion 406 Secondary ion

Claims (8)

Forming a release layer on the substrate,
Forming a relaxation layer on the release layer;
Forming a thin film or thin film laminate on the relaxation layer,
Bonding a support to the outermost surface of the thin film or the outermost surface of the thin film laminate,
Peeling the release layer from the substrate;
The surface of the release layer is irradiated with primary ions, the release layer, the relaxation layer, the thin film or the thin film laminate are sputtered in this order, and secondary ions are detected to detect a film of the thin film or the thin film laminate. A method for analyzing a sample, characterized by analyzing the concentration of impurities therein. In claim 1,
The method for analyzing a sample, wherein the release layer has a higher fluorine concentration than the relaxation layer. In claim 2,
As the release layer and the relaxation layer, the fluorine concentration is 1 × 10 ¹⁷ atoms / cm ³ or more and 2 × 10 ¹⁹ atoms / cm ³ or less, and the hydrogen concentration is 1 × 10 ²¹ atoms / cm ³ or more and 1 × 10 ²² atoms. / Cm ³ or less, the carbon concentration is 1 × 10 ¹⁵ atoms / cm ³ or more and 2 × 10 ¹⁸ atoms / cm ³ or less, and the nitrogen concentration is 1 × 10 ¹⁸ atoms / cm ³ or more and 1 × 10 ²⁰ atoms / cm 3. ^{3. A} method for analyzing a sample, comprising forming a film having an oxygen concentration of 3 × 1 or less and an oxygen concentration of 1 × 10 ¹⁵ atoms / cm ³ or more and 1 × 10 ¹⁹ atoms / cm ³ or less. In any one of Claim 1 thru | or 3,
The support has a base material and an adhesive provided on one main surface of the base material,
The method for analyzing a sample, wherein the adhesive material contains organopolysiloxane as a main component. In any one of Claims 1 thru | or 4,
A method for analyzing a sample, wherein an amorphous silicon film containing fluorine is formed as the release layer. Forming a release layer on the substrate,
Forming a relaxation layer on the release layer;
Forming a thin film or thin film laminate on the relaxation layer,
Bonding a support to the outermost surface of the thin film or the outermost surface of the thin film laminate,
Peeling the release layer from the substrate;
The method for producing an analytical sample, wherein the release layer has a surface irradiated with primary ions in order to perform SIMS analysis of an impurity concentration in the film of the thin film or the thin film stack. A support;
A thin film or thin film laminate on the support;
A relaxation layer on the thin film or the thin film laminate;
A release layer on the relaxation layer,
The support, the thin film or the thin film laminate, the relaxation layer, and the release layer are separated from the substrate by the release layer,
The analysis sample, wherein the release layer has a surface irradiated with primary ions for SIMS analysis of an impurity concentration in the film of the thin film or the thin film stack. Forming a release layer on the substrate;
Forming a relaxation layer on the release layer;
Forming an analysis object on the relaxation layer;
A step of bonding a support on the analysis target;
And a step of peeling the release layer, the relaxation layer, the analysis object , and the support from the substrate.

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