A method for the preparation of a sample for detection by a glow discharge mass spectrometer

Abstract

The application provides a preparation method of a sample for glow discharge mass spectrometer detection, comprising the following steps: a) combining a sample to be detected with gallium through a PTFE mold to obtain a sample for glow discharge mass spectrometer detection. The application can determine the In and other impurity contents in the sample except gallium by solidifying small-size, irregular block samples and gallium together or pressing a powder sample on the surface of Ga. The method and the In wrapping sample preparation method are complementary to each other, and can obtain more comprehensive impurity information of the sample. Compared with the sample preparation method of tantalum spoon, the method widens the sample size range that can be determined, and also avoids the problem that the powder sample is sucked away by the instrument during vacuumizing. Therefore, the method can meet the detection requirements of small block samples and powder samples at the same time, and can be used to determine the In and other impurity contents in irregular block conductive and semiconductive samples and powder samples with a size less than 11 mm.

Description

Technical Field

[0001] This invention relates to the field of analytical detection technology, and more specifically, to a method for preparing samples for detection by glow discharge mass spectrometry. Background Technology

[0002] In recent decades, glow discharge mass spectrometry (GDMS) has become the most powerful tool for rapid multi-element analysis of ultrapure solid materials. It boasts excellent detection limits and an extremely wide linear dynamic range, and is currently widely used in the conductor and semiconductor industries. It can directly measure conductor and semiconductor samples that meet the instrument's size requirements. For example, the Astrum GDMS manufactured by NuInstruments accepts flat, blocky samples with dimensions of 11-40 × 11-40 × 1-20 mm, and typical rod-shaped samples with dimensions of 2-3 × 2-3 × 22 mm. For some small, irregularly shaped samples (less than 11 mm) and powder samples, they must be wrapped in flake In or placed on a rod-shaped tantalum spoon for measurement.

[0003] However, an increasing number of semiconductor products now have requirements regarding the In content. If In is used for encapsulation, In will sputter during detection, making it impossible to obtain the In content of the product. Furthermore, the sample size placed in the tantalum spoon must be less than 3 mm; samples with dimensions between 3-11 mm cannot be measured. Additionally, if a tantalum spoon is used to hold powder samples, they are easily removed during instrument vacuuming. Therefore, providing a sample preparation method for glow discharge mass spectrometry that simultaneously meets the detection requirements of small block samples and powder samples has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing samples for glow discharge mass spectrometry detection, which can simultaneously meet the detection requirements of small block samples and powder samples, and can be used to determine the content of In and other impurities in irregular block conductors, semiconductor samples and powder samples with a size of less than 11 mm.

[0005] This invention provides a method for preparing a sample for glow discharge mass spectrometry detection, comprising the following steps:

[0006] a) The sample to be tested is bonded to gallium through a PTFE mold to obtain a sample for detection by glow discharge mass spectrometry.

[0007] Preferably, the sample to be tested in step a) is a block sample, and the bonding method is to solidify the block sample in gallium.

[0008] Preferably, the block sample is a conductor sample with a length and / or width of less than 11 mm, or a semiconductor sample with a length and / or width of less than 11 mm.

[0009] Preferably, the process of solidifying the bulk sample in gallium specifically involves:

[0010] A block sample with a diameter of 7mm to 9mm is placed in a PTFE mold. Liquid gallium is then added to completely encapsulate the block sample. After cooling and solidification of the gallium, the sample is removed.

[0011] Preferably, the cooling process specifically includes:

[0012] Place the PTFE mold in a liquid nitrogen cup containing liquid nitrogen.

[0013] Preferably, the sample to be tested in step a) is a powder sample, and the bonding method is to adhere the powder sample to the gallium surface.

[0014] Preferably, the process of adhering the powder sample to the gallium surface specifically includes:

[0015] Liquid gallium is placed in a PTFE mold, cooled until the gallium solidifies, and then removed. A powder sample is then pressed onto the gallium surface, with the diameter of the powder sample adhering to the gallium surface being 4 mm to 9 mm.

[0016] Preferably, the PTFE mold in step a) includes a first structural unit and a second structural unit. The first structural unit provides a loading plane, and the second structural unit has a through hole. After the two are assembled, one side of the through hole is covered by the loading plane to form a mold cavity structure. The first structural unit and the second structural unit are fixed by screws.

[0017] Preferably, before using the PTFE mold, it further includes:

[0018] First, clean the first and second structural units with 20wt% to 40wt% nitric acid for 1 to 10 minutes, then rinse them with water and air dry them in a clean bench. Finally, assemble the first and second structural units together with screws.

[0019] Preferably, the gallium in step a) is high-purity gallium with a purity greater than 99.9999%, and the In content in the gallium is less than 1 ppb; the amount of gallium used is 1 ml to 2 ml.

[0020] This invention provides a method for preparing samples for glow discharge mass spectrometry (GFMS) detection, comprising the following steps: a) combining the sample to be tested with gallium using a PTFE mold to obtain a sample for GFMS detection. This invention, by solidifying small (less than 11 mm), irregular block samples with gallium, or pressing powder samples onto the surface of Ga, can determine the content of In and other impurities besides gallium in the sample. This method complements the In-encapsulated sample preparation method, providing more comprehensive impurity information. Furthermore, compared to the tantalum spoon sample preparation method (less than 3 mm), this method broadens the range of measurable sample sizes (less than 11 mm) and avoids the problem of powder samples being removed by the instrument during vacuuming when loaded with tantalum spoons. Therefore, it can simultaneously meet the detection requirements of small block samples and powder samples, and can be used to determine the content of In and other impurities in irregular block conductors, semiconductors, and powder samples with a size less than 11 mm. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the first and second structural units of the PTFE mold described in this invention. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention provides a method for preparing a sample for glow discharge mass spectrometry detection, comprising the following steps:

[0024] a) The sample to be tested is bonded to gallium through a PTFE mold to obtain a sample for detection by glow discharge mass spectrometry.

[0025] This invention provides a method for preparing samples for glow discharge mass spectrometry, which can simultaneously meet the detection requirements of small block samples and powder samples, and can be used to determine the content of In and other impurities in irregular block conductors, semiconductors and powder samples with a size of less than 11 mm.

[0026] In a preferred embodiment of the present invention, the sample to be tested is a block sample; the preferred method of bonding is to solidify the block sample in gallium.

[0027] In this invention, the block sample is preferably a conductor sample with a length and / or width of less than 11 mm, or a semiconductor sample with a length and / or width of less than 11 mm.

[0028] In this invention, the process of solidifying the bulk sample in gallium is preferably as follows:

[0029] A block sample with a diameter of 7mm to 9mm is placed in a PTFE mold. Liquid gallium is then added to completely encapsulate the block sample. After cooling and solidification, the sample is removed. In this invention, when the size of the block sample is small, multiple samples can be joined together, but the combined diameter should also be between 7mm and 9mm.

[0030] In this invention, to ensure good sealing, the bulk sample needs to be surrounded by gallium.

[0031] In this invention, the cooling process is preferably specifically as follows:

[0032] Place the PTFE mold in a liquid nitrogen cup containing liquid nitrogen.

[0033] In another preferred embodiment of the present invention, the sample to be tested is a powder sample; the bonding method is preferably to adhere the powder sample to the gallium surface.

[0034] In this invention, the powder sample preferably includes a conductor powder sample, a semiconductor powder sample, and an insulator powder sample.

[0035] In this invention, the process of adhering the powder sample to the gallium surface is preferably as follows:

[0036] Liquid gallium is placed in a PTFE mold, cooled until the gallium solidifies, and then removed. A powder sample is then pressed onto the gallium surface, with the diameter of the powder sample adhering to the gallium surface being 4 mm to 9 mm.

[0037] In this invention, the cooling process is preferably specifically as follows:

[0038] Place the PTFE mold in a liquid nitrogen cup containing liquid nitrogen.

[0039] In this invention, for conductor powder samples and semiconductor powder samples, the diameter of the powder sample adhering to the gallium surface is preferably 7 mm to 9 mm; for insulator powder samples, the diameter of the powder sample adhering to the gallium surface is 4 mm to 5 mm.

[0040] In this invention, the PTFE mold includes a first structural unit (referred to as mold 1 in the drawings) and a second structural unit (referred to as mold 2 in the drawings), see [reference]. Figure 1As shown; the first structural unit provides a loading plane, and the second structural unit has a through hole. After the two are assembled, one side of the through hole is covered by the loading plane to form a mold cavity structure; the first structural unit and the second structural unit are fixed by screws; in a preferred embodiment of the present invention, the first structural unit and the second structural unit are each provided with 4 screw holes, which can enable the two to be tightly fixed by screws.

[0041] In this invention, the PTFE mold preferably further includes, before use:

[0042] First, clean the first and second structural units with 20wt% to 40wt% nitric acid for 1 to 10 minutes, then rinse them with water, and finally air dry them in a clean bench. Then, assemble the first and second structural units together with screws.

[0043] More preferably:

[0044] First, clean the first and second structural units with 30wt% nitric acid for 5 minutes, then rinse them with water, and finally dry them in a clean bench. Then, assemble the first and second structural units together with screws.

[0045] The present invention uses the above-mentioned PTFE mold. On the one hand, the PTFE mold has high purity, is easy to clean, and will not introduce metal impurities; on the other hand, it is convenient to use, easy to assemble and disassemble, and facilitates sample demolding, so that the entire sample preparation process can be completed in a Class 100 clean bench.

[0046] In this invention, the gallium is preferably high-purity gallium with a purity greater than 99.9999%, and the In content in the gallium is less than 1 ppb; the amount of gallium used is preferably 1 ml to 2 ml; wherein, the amount of gallium used in combination with a block sample is preferably 1 ml to 1.5 ml; and the amount of gallium used in combination with a powder sample is preferably 1.6 ml to 2 ml.

[0047] This invention selects gallium because of its low melting point, which makes it easy to solidify bulk samples with gallium; its low hardness allows powdered samples to easily adhere to the gallium surface; and it is easy to obtain high-purity gallium, with impurities in gallium having little impact on the final sample measurement results.

[0048] The present invention does not impose any special restrictions on the further analysis of the prepared samples using a glow discharge mass spectrometer; a DC glow discharge mass spectrometer well-known to those skilled in the art can be used. Preferably, the prepared sample is introduced into a sample cell, cooled for 4-6 minutes, and then analyzed under the set glow discharge parameters. In this invention, the set glow discharge parameters include a discharge current of 1.5 mA-2 mA and a discharge voltage of 950 V-1050 V.

[0049] This invention provides a method for preparing samples for glow discharge mass spectrometry (GFMS) detection, comprising the following steps: a) combining the sample to be tested with gallium using a PTFE mold to obtain a sample for GFMS detection. This invention, by solidifying small (less than 11 mm), irregular block samples with gallium, or pressing powder samples onto the surface of Ga, can determine the content of In and other impurities besides gallium in the sample. This method complements the In-encapsulated sample preparation method, providing more comprehensive impurity information. Furthermore, compared to the tantalum spoon sample preparation method (less than 3 mm), this method broadens the range of measurable sample sizes (less than 11 mm) and avoids the problem of powder samples being removed by the instrument during vacuuming when loaded with tantalum spoons. Therefore, it can simultaneously meet the detection requirements of small block samples and powder samples, and can be used to determine the content of In and other impurities in irregular block conductors, semiconductors, and powder samples with a size less than 11 mm.

[0050] To further illustrate the present invention, the following embodiments will be described in detail.

[0051] Example 1

[0052] (1) Clean the first and second structural units of the PTFE mold for gallium production with 30% nitric acid for 5 minutes, rinse with pure water, dry in a clean bench, and then assemble the first and second structural units together with 4 screws.

[0053] (2) Transfer 2ml of liquid gallium into a PTFE mold, place the mold in a liquid nitrogen cup containing liquid nitrogen, and remove it after the gallium solidifies;

[0054] (3) Unscrew the four screws to take out the prepared gallium sample. After the gallium is dried in the clean bench, press the Bi2O3 powder sample onto the surface of the Ga. The diameter of the Bi2O3 powder sample pressed onto the Ga is between 7 mm and 9 mm. This will give you a sample for detection by glow discharge mass spectrometry.

[0055] The sample prepared by the method provided in Example 1 was pushed into the sample cell and cooled for 5 minutes. Then, under the set glow discharge parameters, specifically, a discharge current of 1.5 mA and a discharge voltage of 950 V, it was analyzed using an Astrum DC glow discharge mass spectrometer from Nu Instruments. The results are shown in Table 1.

[0056] Table 1. Detection results of Bi2O3 in samples

[0057]

[0058] Table 1 shows the detection data of Bi2O3. The sample surface was poorly contaminated with impurities. After 15 minutes of sputtering, the surface contaminants were all removed. The relative standard deviations of the elements were all within 20%, indicating good precision.

[0059] Example 2

[0060] (1) Clean the first and second structural units of the PTFE mold for gallium production with 30% nitric acid for 5 minutes, rinse with pure water, dry in a clean bench, and then assemble the first and second structural units together with 4 screws.

[0061] (2) Place 9 2-3 ​​mm granular antimony samples in the center of the first structural unit of the PTFE mold, and the diameter of the samples placed in the PTFE mold together is between 7 mm and 9 mm. Then, take 1.2 ml of liquid gallium into the mold, place the mold in a liquid nitrogen cup containing liquid nitrogen, and take it out after the gallium solidifies.

[0062] (3) Unscrew the four screws to remove the prepared sample and obtain the sample for detection by glow discharge mass spectrometer.

[0063] The sample prepared by the method provided in Example 2 was pushed into the sample cell and cooled for 5 minutes. Then, under the set glow discharge parameters, specifically, a discharge current of 1.5 mA / 1050 V and a discharge voltage, it was analyzed using an Astrum DC glow discharge mass spectrometer from NuInstruments. The results are shown in Table 2.

[0064] Table 2. Detection results of antimony in samples.

[0065]

[0066] Table 2 shows the detection data for Sb. After 30 minutes of sputtering, the surface contaminants on the sample surface were removed, and the relative standard deviations of the elements were all within 20%, indicating good precision.

[0067] Example 3

[0068] (1) Clean the first and second structural units of the PTFE mold for gallium production with 30% nitric acid for 5 minutes, rinse with pure water, dry in a clean bench, and then assemble the first and second structural units together with 4 screws.

[0069] (2) Place a 5×8×2mm block tellurium sample at the center of the first structural unit of the PTFE mold, then transfer 1.0ml of liquid gallium into the mold, place the mold in a liquid nitrogen cup containing liquid nitrogen, and remove it after the gallium solidifies.

[0070] (3) Unscrew the four screws to remove the prepared sample and obtain the sample for detection by glow discharge mass spectrometer.

[0071] The sample prepared by the method provided in Example 3 was pushed into the sample cell and cooled for 5 minutes. Then, under the set glow discharge parameters, specifically, at a discharge current of 2mA / 1000V and a discharge voltage, it was analyzed using an Astrum DC glow discharge mass spectrometer from Nu Instruments. The results are shown in Table 3.

[0072] Table 3. Detection results of tellurium in the samples.

[0073]

[0074] Table 3 shows the detection data for Te. After 45 minutes of sputtering, the surface contaminants on the sample surface were removed, and the relative standard deviations of the elements were all within 20%, indicating good precision.

[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a sample for detection by glow discharge mass spectrometry, comprising the following steps: a) The sample to be tested is bonded to gallium through a PTFE mold to obtain a sample for detection by glow discharge mass spectrometry; The gallium is high-purity gallium; The sample to be tested in step a) is a block sample, and the bonding method is to solidify the block sample inside gallium; or, The sample to be tested in step a) is a powder sample, and the bonding method is to adhere the powder sample to the solidified gallium surface.

2. The preparation method according to claim 1, characterized in that, The block sample is a conductor sample with a length and / or width of less than 11 mm, or a semiconductor sample with a length and / or width of less than 11 mm.

3. The preparation method according to claim 1, characterized in that, The process of solidifying a bulk sample in gallium is as follows: A block sample with a diameter of 7mm to 9mm is placed in a PTFE mold. Liquid gallium is then added to completely encapsulate the block sample. After cooling and solidification of the gallium, the sample is removed.

4. The preparation method according to claim 3, characterized in that, The cooling process is specifically as follows: Place the PTFE mold in a liquid nitrogen cup containing liquid nitrogen.

5. The preparation method according to claim 1, characterized in that, The process of adhering powder samples to the gallium surface is as follows: Liquid gallium is placed in a PTFE mold, cooled until the gallium solidifies, and then removed. A powder sample is then pressed onto the gallium surface, with the diameter of the powder sample adhering to the gallium surface being 4mm to 9mm.

6. The preparation method according to claim 1, characterized in that, The PTFE mold described in step a) includes a first structural unit and a second structural unit. The first structural unit provides a loading plane, and the second structural unit has a through hole. After the two are assembled, one side of the through hole is covered by the loading plane to form a mold cavity structure. The first structural unit and the second structural unit are fixed by screws.

7. The preparation method according to claim 6, characterized in that, Before use, the PTFE mold also includes: First, clean the first and second structural units with 20wt%~40wt% nitric acid for 1min~10min, then rinse them with water, and then air dry them in a clean bench. Finally, assemble the first and second structural units together with screws.

8. The preparation method according to claim 1, characterized in that, The gallium mentioned in step a) is high-purity gallium with a purity greater than 99.9999%, and the In content in the gallium is less than 1 ppb; the amount of gallium used is 1 ml to 2 ml.

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