Metal precursor pyrolysis characteristic detection method based on thermal mass spectrometry

Abstract

The invention discloses a thermal mass spectrometry-based metal precursor pyrolysis characteristic detection method, relates to the technical field of precursor pyrolysis characteristic detection, and aims to solve the problem that the comprehensive purity and impurity content of a product cannot be comprehensively evaluated by a current metal precursor characterization method. A metal precursor is promoted to volatilize in a constant-temperature or temperature-rising heating mode under the protection of inert gas, a thermal weight loss curve is drawn according to the correlation between residual weight and time and temperature, meanwhile, along with decomposition of substances, the weight loss curve jumps, different types of molecular ion fragments can be detected through the combined mass spectrum, and qualitative analysis is achieved. The volatilization rate and the decomposition characteristic of the precursor are represented through a curve and a molecular ion peak, volatilization and decomposition products are quantified through the thermal weight loss proportion and the acquisition proportion of molecular ion fragments, and finally, non-volatile evaporation residues remaining are used as the non-volatile matter impurity content of ultra-pure chemicals. Qualitative and quantitative detection of the purity, impurity components and decomposition characteristics of the metal precursor is realized.

Description

Technical Field

[0001] This invention relates to the field of precursor pyrolysis characteristic testing technology, and more specifically, to a method for testing the pyrolysis characteristics of metal precursors based on thermo-mass spectrometry. Background Technology

[0002] Precursor materials, as core materials in thin film deposition processes for integrated circuit manufacturing, occupy an important position in the chip manufacturing field. They are one of the key materials restricting the development and iterative upgrading of integrated circuit technology. Metal precursor materials are mainly deposited using chemical vapor deposition (CVD) and atomic layer vapor deposition (ALD) processes to deposit metals and metal compounds as core functional layers such as metal wires, etch stop layers, gate oxide layers, and capacitors. Especially with the miniaturization and increasing complexity of integrated circuit devices, the consumption of metal precursors is increasing, and the quality requirements are also becoming higher. Their purity, impurity content, and pyrolysis characteristics have become the main factors restricting the high-end development of chip manufacturing processes and equipment, thus becoming a bottleneck problem for the integrated circuit industry.

[0003] Currently, characterization methods for metal precursors mainly include XRD, NMR, IR, RAMAN, and ICPMS. Among these, XRD, IR, and RAMAN are used to evaluate the crystal structure and functional group types of metal precursors, but the equipment is expensive and the evaluation targets are limited. XRD and RAMAN are only suitable for evaluating crystal structures and cannot evaluate most organometallic precursors. IR can only evaluate the types of functional groups and their interactions, but cannot quantify impurities, and is not applicable to metal precursors without organic functional groups. NMR has certain qualitative and quantitative functions, but is limited to organometallic precursors containing characteristic elements such as C, H, P, and Cl. It cannot test inorganic metal precursors or those without characteristic elements, and it cannot qualitatively and quantitatively test different types of impurities. ICPMS is only suitable for detecting the content of elemental impurities in metal precursors, and certain pretreatment is required before testing. Organic impurities are lost during pretreatment, making it impossible to comprehensively evaluate the overall purity and impurity content of the product. Summary of the Invention

[0004] The purpose of this invention is to provide a method for detecting the pyrolysis characteristics of metal precursors based on thermo-mass spectrometry (TCMS), which can simultaneously determine the purity, impurity content, decomposition characteristics and stability, thermogravimetric curves, and other items of solid and liquid metal precursors, enabling qualitative and quantitative analysis of the purity and physicochemical properties of metal precursors.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A method for detecting the pyrolysis characteristics of metal precursors based on thermo-mass spectrometry includes the following steps:

[0007] (1) Open the inert gas switch valve, open the glove box to replace the atmosphere in the glove box, and after the replacement is completed, open the internal circulation, open the gas circuit switch of the thermogravimetric analyzer, the bridging temperature control system and the mass detector, and then turn on their respective power supplies and select the type of purge gas for the thermogravimetric analyzer and the carrier gas for the mass detector.

[0008] (2) Set the sample weighing capacity of the precision balance and the initial temperature of the thermogravimetric analyzer; set the termination temperature of the thermogravimetric analyzer according to the boiling point, decomposition temperature and decomposition temperature of the metal precursor and the decomposition product; set the heating rate of the thermogravimetric analyzer according to the initial temperature and termination temperature; set the capillary length and temperature control of the bridging system according to the boiling point, decomposition temperature and decomposition temperature of the metal precursor and the decomposition product, and set the mass number range of the mass detector.

[0009] (3) After the parameters are set, the precision balance and thermogravimetric analyzer are calibrated and zeroed, and the mass detector is tuned. After the thermogravimetric analyzer furnace temperature reaches the initial temperature and the baseline of the weight loss curve is stable, the bridging temperature control system reaches the set constant temperature and the mass detector reaches the optimal tuning parameters, the sample is measured. For liquid and solid metal precursors, an open weighing boat is used (the material can be ceramic, platinum and other materials depending on the properties of the precursor, with the selection condition being that it does not react with the material of the weighing boat). For gaseous metal precursors, a closed weighing boat is required (the material selection is based on the same criteria as above).

[0010] (4) After weighing the sample, click the start button to perform the measurement. The measurement results will automatically output the thermogravimetric curve, the proportion of non-volatile residues after evaporation and the purity data. At the same time, the thermal decomposition temperature can be observed for the thermogravimetric curve. The mass spectrometer detector outputs the mass number proportion and retention time. Ion fragment extraction is performed for each mass spectrum peak to obtain the mass spectrum bar chart of each mass spectrum peak. Based on the fragment ion peaks in the mass spectrum bar chart and the database search, the functional group types and numbers of the metal precursor, as well as the types and proportions of the decomposed substances, can be inferred.

[0011] Preferably, in step (1), the inert gas is argon, helium or nitrogen.

[0012] Preferably, in step (2), the sample weight of the precision balance is set to 0-1g (the balance accuracy is 0.1 micrograms).

[0013] Preferably, in step (2), the initial temperature of the thermogravimetric analyzer is set to -20 to 100°C.

[0014] Preferably, in step (2), the termination temperature of the thermogravimetric analyzer is set to 0-1100℃.

[0015] Preferably, in step (2), the heating rate of the thermogravimetric analyzer is set to 0-500℃ / min.

[0016] Preferably, in step (2), the capillary length of the bridging system is set to 0-100m, and the temperature of the bridging system is controlled to be 0-350℃.

[0017] Preferably, in step (2), the mass number range of the mass detector is set to 10 to 350 amu.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention promotes the volatilization of metal precursors by constant or incremental heating under inert gas protection. A thermogravimetric curve is plotted based on the correlation between residual weight and time and temperature. Simultaneously, the weight loss curve exhibits abrupt changes as the substance decomposes. Combined mass spectrometry can detect different types of molecular ion fragments for qualitative analysis. The volatilization rate and decomposition characteristics of the precursor are characterized by the curve and molecular ion peaks. The volatilization and decomposition products are quantified using the proportion of thermogravimetric loss and the acquisition ratio of molecular ion fragments. Finally, the remaining unvolatilized evaporation residue is used as the non-volatile impurity content of the ultrapure chemical, achieving qualitative and quantitative detection of the purity, impurity components, and decomposition characteristics of the metal precursor. Attached Figure Description

[0020] Figure 1 This is a graph showing the measurement results of the automatically output thermogravimetric curve, the proportion of non-volatile residue after evaporation, and the purity data in Example 1 of the present invention.

[0021] Figure 2 This is a graph showing the results of determining the types and proportions of decomposed substances in Example 1 of the present invention;

[0022] Figure 3 This is a graph showing the measurement results of the automatically output thermogravimetric curve, the proportion of non-volatile residue after evaporation, and the purity data in Example 2 of the present invention.

[0023] Figure 4 This is a graph showing the results of the determination of the types and proportions of decomposed substances in Example 2 of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available. For any specific techniques or conditions not specified in the examples, they can be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions.

[0026] Example 1

[0027] This embodiment provides a method for detecting the pyrolysis characteristics of metal precursors based on thermo-mass spectrometry (TCMS). The detection method is as follows:

[0028] Open the inert gas switch valve; nitrogen can be used as the inert gas. Open the glove box to purge the glove box atmosphere. After purging, start the internal circulation. Turn on the gas circuit switches for the thermogravimetric analyzer, bridging temperature control system, and mass detector, and then turn on their respective power supplies. Select helium as the purge gas for the thermogravimetric analyzer and the carrier gas for the mass detector. Set the sample weight on the precision balance to 20 mg. Set the initial temperature of the thermogravimetric analyzer to 35°C. Set the final temperature of the thermogravimetric analyzer to 300°C. Set the heating rate of the thermogravimetric analyzer to 10°C / min. Set the bridging system... The capillary length (10cm) and temperature control (260℃) were set, and the mass number range of the mass detector was set to 10-350 amu. After setting the parameters, the precision balance and thermogravimetric analyzer were calibrated and zeroed. The mass detector was tuned. Sample determination was performed after the thermogravimetric analyzer heating furnace temperature reached the initial temperature, the baseline of the weight loss curve stabilized, the bridging temperature control system reached the set constant temperature, and the mass detector reached the optimal tuning parameters. 20mg of aluminum trichloride solid sample was weighed in an open weighing boat, and the start button was clicked to begin the measurement. The results, including the thermogravimetric curve, the percentage of non-volatile residue after evaporation, and purity data, were automatically output as follows: Figure 1 As shown, the mass spectrometer detector outputs the mass percentage and retention time. Ion fragment extraction is performed on each mass peak to obtain a mass spectrum histogram. Based on the fragment ion peaks in the mass spectrum histogram and database searches, the types and numbers of functional groups in the metal precursor are inferred, as well as the types and percentages of decomposed substances. The results are as follows: Figure 2 As shown.

[0029] Figure 1 Results: The results showed that the non-volatile purity of solid aluminum trichloride was 99.72%, the non-volatile residue content was 0.28%, the thermal weight loss curve was smooth and there was no decomposition, and the temperature point at which 50% weight loss occurred was 135℃.

[0030] Figure 2 Results: The results showed that the main mass spectrometry peak of aluminum trichloride was at 11.13 min. Molecular ion peak extraction yielded a large number of chloride ion fragment peaks, AlCl ion fragment peaks, AlCl2 ion fragment peaks, AlCl3 ion fragments, and dimer molecular ion fragment peaks.

[0031] Example 2

[0032] This embodiment provides a method for detecting the pyrolysis characteristics of metal precursors based on thermo-mass spectrometry (TCMS). The detection method is as follows:

[0033] Open the inert gas switch valve; nitrogen can be used as the inert gas. Open the glove box to purge the glove box atmosphere. After purging, start the internal circulation. Turn on the gas circuit switches for the thermogravimetric analyzer, bridging temperature control system, and mass detector, and then turn on their respective power supplies. Select helium as the purge gas for the thermogravimetric analyzer and the carrier gas for the mass detector. Set the sample weight on the precision balance to 20 mg. Set the initial temperature of the thermogravimetric analyzer to 35°C, the final temperature of the thermogravimetric analyzer to 500°C, the heating rate of the thermogravimetric analyzer to 16°C / min, and the capillary length of the bridging system to [the appropriate value]. The temperature control (10cm) and mass detector (260℃) were set, with the mass number range set to 10-350 amu. After parameter setting, the precision balance and thermogravimetric analyzer were calibrated and zeroed. The mass detector was tuned. Sample determination was performed after the thermogravimetric analyzer heating furnace temperature reached the initial temperature, the baseline of the weight loss curve stabilized, the bridging temperature control system reached the set constant temperature, and the mass detector reached its optimal tuning parameters. 20 mg of tris(dimethylamino)cyclopentadienylzirconium liquid sample was weighed in an open sample boat. After weighing, the start button was clicked to begin the determination. The thermogravimetric curve, the percentage of non-volatile evaporation residue, and purity data were automatically output as follows: Figure 3 As shown, the mass spectrometer detector outputs the mass percentage and retention time. Ion fragment extraction is performed on each mass peak to obtain a mass spectrum histogram. Based on the fragment ion peaks in the mass spectrum histogram and database searches, the types and numbers of functional groups in the metal precursor are inferred, as well as the types and percentages of decomposed substances. The results are as follows: Figure 4 As shown.

[0034] Figure 3 Results: The results showed that the non-volatile purity of liquid tris(dimethylamino)cyclopentadienyl zirconium was 98.87%, the non-volatile residue content was 1.13%, the bulging of the thermogravimetric curve indicated decomposition at 132℃, and the temperature point at which 50% weight loss occurred was 146℃.

[0035] Figure 4 Results: The results showed that the main mass spectrum peak of tris(dimethylamino)cyclopentadienyl zirconium was at 8.53 min. Molecular ion peak extraction yielded a large number of dimethylamino ion fragment peaks, cyclopentadienyl ion fragment peaks, bis(dimethylamino)zirconium ion fragment peaks, tris(dimethylamino)zirconium ion fragments, and molecular ion fragment peaks of tris(dimethylamino)cyclopentadienyl zirconium.

[0036] Metal precursors are classified into inorganic metal precursors and organometallic precursors, and exist in solid, liquid, and gaseous states. The vast majority are ultrapure chemicals with good reactivity, and the boiling points of different types vary greatly, making the development of a universally applicable method for evaluating purity and stability extremely difficult. This invention induces the volatilization of metal precursors under inert gas protection using isothermal or incremental heating. Thermogravimetric curves are plotted based on the correlation between residual weight and time and temperature. Simultaneously, the weight loss curve exhibits abrupt changes as the substance decomposes. Mass spectrometry is used to detect different types of molecular ion fragments for qualitative analysis. The volatilization rate and decomposition characteristics of the precursor are characterized by the curves and molecular ion peaks. The volatilization and decomposition products are quantified using the proportion of thermogravimetric loss and the acquisition ratio of molecular ion fragments. The final unvolatilized evaporation residue is used as the non-volatile impurity content of the ultrapure chemical, achieving qualitative and quantitative detection of the purity, impurity components, and decomposition characteristics of metal precursors.

[0037] The embodiments disclosed in this invention are preferred embodiments, but are not limited thereto. Those skilled in the art can easily understand the spirit of this invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of this invention, they are all within the protection scope of this invention.

Claims

1. A method for detecting pyrolysis characteristics of a metal precursor based on thermal mass spectrometry, characterized by, The method comprises the following steps: (1) Open the inert gas switch valve, open the glove box to replace the atmosphere of the glove box, open the internal circulation after the replacement is completed, open the gas path switch of the thermal gravimetric analyzer, the bridge connection temperature control system and the mass detector, then turn on the power of each, select the types of the thermal gravimetric analyzer purge gas and the mass detector carrier gas; (2) Set the sample weight of the precision balance, the initial temperature of the thermal gravimetric analyzer; set the termination temperature of the thermal gravimetric analyzer according to the boiling point, decomposition temperature of the metal precursor and the boiling point temperature of the decomposition product; set the temperature rise rate of the thermal gravimetric analyzer according to the initial temperature and the termination temperature; set the capillary length and temperature control of the bridge connection system according to the boiling point, decomposition temperature of the metal precursor and the boiling point temperature of the decomposition product, and set the mass number range of the mass detector; (3) After the parameter setting is completed, calibrate and reset the precision balance and the thermal gravimetric analyzer, tune the mass detector, and then perform sample determination when the heating furnace temperature of the thermal gravimetric analyzer reaches the initial temperature, the weight loss curve baseline is stable, the bridge connection temperature control system reaches the set constant temperature and the mass detector reaches the optimal tuning parameters; use an open sample weighing boat for liquid and solid metal precursors, and use a sealed sample weighing boat for gaseous metal precursors; (4) After weighing, click the start button to perform determination, and the determination results are automatically output as the thermal gravimetric curve, the evaporation and non-volatility residue ratio and the purity data, and the thermal decomposition temperature result can be observed for the thermal gravimetric curve, the mass number ratio and the retention time are output by the mass spectrometer, the mass spectrum column chart of each mass spectrum peak is obtained by ion fragment extraction for each mass spectrum peak, the functional group type and the number of the metal precursor, and the type and the ratio of the decomposition product are inferred according to the fragment ion peak of the mass spectrum column chart and the database retrieval.

2. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (1), the inert gas is argon, helium or nitrogen.

3. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (2), the sample weight of the precision balance is set to 0-1 g.

4. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (2), the initial temperature of the thermal gravimetric analyzer is set to -20-100℃.

5. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (2), the termination temperature of the thermal gravimetric analyzer is set to 0-1100℃.

6. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (2), the temperature rise rate of the thermal gravimetric analyzer is set to 0-500℃ / min.

7. The method of claim 1, wherein the method is a thermal mass spectrometry based method. In step (2), the capillary length of the bridge connection system is set to 0-100 m, and the temperature control of the bridge connection system is set to 0-350℃.

8. The method of claim 1, wherein the metal precursor pyrolysis characteristics are detected based on thermogravimetric analysis. In step (2), the mass number range of the mass detector is set to 10-350 amu.

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