Sample preparation method for EBSD detection of nickel-platinum sputtering target material

Abstract

The invention provides a sample preparation method for EBSD (electron back scattered diffraction) detection of a nickel-platinum sputtering target material. The sample preparation method comprises the following steps: (1) cutting a nickel-platinum sputtering target material to obtain a nickel-platinum target block; (2) sequentially carrying out grinding, mechanical polishing and ion polishing on the nickel-platinum target block to obtain a sample to be detected; wherein in the ion polishing process, the voltage is firstly increased and then reduced. The to-be-detected sample prepared by the method is smooth and flat in surface and free of obvious scratches, the diffraction Kikuchi zone of the sample is clear during EBSD detection, and the calibration rate of the sample is relatively high.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetron sputtering, and relates to a sample preparation method for EBSD detection of a nickel-platinum sputtering target. Background Art

[0002] In semiconductor manufacturing technology, metal silicides are widely used in the following aspects: ① preparing a barrier contact layer in a Schottky diode; ② in the technology of very large scale integrated circuit (VLSI) / ultra large scale integrated circuit (ULSI) devices, for the contacts between the source, drain, and gate and metal electrodes. With the development of semiconductor technology, the composition of metal silicides has gradually evolved from the initial TiSi and CoSi compounds to NiSi compounds with low resistivity and low silicon consumption. However, in applications, it has gradually been found that NiSi compounds have poor heat resistance, and the addition of noble metal platinum (Pt) can significantly increase the thermal stability of NiSi compounds. Currently, the mainstream method for preparing NiPtSi compound thin films is to first use a semiconductor substrate with a silicon region, then prepare an ion implantation layer in the silicon region, grow a silicon epitaxial layer thereon, then magnetron sputter a NiPt thin film on the surface of the silicon epitaxial layer using a NiPt target, and finally perform annealing treatment to form a Pt-containing NiSi compound thin film.

[0003] So far, many reports on NiPtSi compound thin films have been published. In particular, there have been many studies on the correlation between different Pt contents and the stability of NiSi compounds and the silicide barrier height. However, the correlation between the NiPt target and the thin film is usually ignored in the studies. In fact, the microstructure of the target, including grain size, microstrain, and preferred orientation, etc., will all affect the subsequent film sputtering. The microstructure of the NiPt target can be detected by electron backscatter diffraction (EBSD), but there is no suitable sample preparation method yet. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a sample preparation method for EBSD detection of a nickel-platinum sputtering target. By means of techniques such as grinding, mechanical polishing, and ion polishing, the surface of the sample to be measured prepared by the present invention is smooth and flat, without obvious scratches. When performing EBSD detection, the diffraction Kikuchi bands of the sample are clear, and the sample calibration rate is relatively high.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a sample preparation method for EBSD detection of a nickel-platinum sputtering target, and the sample preparation method includes:

[0007] (1) Cutting the nickel-platinum sputtering target to obtain a nickel-platinum target block.

[0008] (2) Grind, mechanically polish, and ion-polish the nickel-platinum target block in sequence to obtain a sample to be measured. During the ion-polishing process, the voltage first increases and then decreases.

[0009] It should be noted that in the prior art, during the sample preparation process of nickel-platinum sputtering targets, due to the existence of a relatively thin stress layer on the sample surface, the diffraction pattern is absent or not obvious.

[0010] By means of techniques such as grinding, mechanical polishing, and ion-polishing, the surface of the sample to be measured prepared by the present invention is smooth and flat, without obvious scratches. When performing EBSD detection, the diffraction Kikuchi bands of the sample are clear, with a relatively high resolution, high stability, and at the same time, the sample calibration rate is relatively high, reaching 90% and above, the results are accurate, meeting general requirements, and the effect is good.

[0011] By ion-polishing in the present invention, the stress layer on the sample surface can be removed, making the diffraction pattern obvious. During the ion-polishing process, the voltage first increases and then decreases, which can polish the sample surface more smoothly and make the polishing process more stable.

[0012] Preferably, the purity of the nickel-platinum sputtering target is ≥99.99%, for example, it can be 99.99%, 99.995%, or 99.999%, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0013] In the present invention, the nickel-platinum sputtering target has a high purity to meet the purity requirements of semiconductors for sputtering targets.

[0014] Preferably, in the nickel-platinum sputtering target, the mass ratio of nickel element to platinum element is (40 - 97):(3 - 60). The selection range of nickel element (40 - 97) can be, for example, 40, 55, 70, 85, 90, 95, or 97, etc.; the selection range of platinum element (3 - 60) can be, for example, 3, 5, 10, 15, 30, 45, or 60, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0015] Preferably, the cutting method in step (1) includes wire cutting.

[0016] Preferably, the size of the nickel-platinum target block is (8 - 15) mm × (8 - 15) mm × (8 - 15) mm, for example, it can be 9×9×9 mm, 10×10×10 mm, or 12×12×12 mm, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0017] Preferably, the grinding includes first grinding and second grinding in sequence.

[0018] Preferably, the first grinding uses SiO sandpaper with a grit size of 200# - 300#, such as 200#, 220#, 250#, 280#, or 300#, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable. 2 Preferably, the second grinding uses SiO sandpaper with a grit size of 900# - 1100#, such as 900#, 950#, 1000#, 1050#, or 1100#, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0019] Preferably, the mechanical polishing includes first mechanical polishing, second mechanical polishing, and third mechanical polishing performed in sequence. 2

[0020] Preferably, the first mechanical polishing uses a diamond suspension; the particle size D50 of the diamond particles in the diamond suspension is 2 - 5 μm, such as 2 μm, 3 μm, 4 μm, or 5 μm, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0021]

[0022] Preferably, the time for the first mechanical polishing is 5 - 10 min, such as 5 min, 6 min, 7 min, 8 min, 9 min, or 10 min, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0023]

[0024] Preferably, the second mechanical polishing uses an alumina suspension; the particle size D50 of the alumina particles in the alumina suspension is 0.1 - 0.5 μm, such as 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, or 0.5 μm, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0025] Preferably, the time for the second mechanical polishing is 10 - 20 min, such as 10 min, 12 min, 14 min, 16 min, 18 min, or 20 min, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0026] Preferably, the third mechanical polishing uses a silica suspension; the particle size D50 of the silica particles in the silica suspension is 40 - 80 nm, such as 40 nm, 50 nm, 60 nm, 70 nm, or 80 nm, etc., but is not limited to the listed values. Other unlisted values within this range are also applicable.

[0026] Preferably, the time of the third mechanical polishing is 20 - 50 min. For example, it can be 20 min, 25 min, 30 min, 35 min, 40 min, 45 min or 50 min, etc., but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0027] Preferably, the ions used in the ion polishing include argon ions.

[0028] Preferably, the ion polishing includes first ion polishing, second ion polishing, third ion polishing and fourth ion polishing carried out in sequence; the voltage gradients of the first ion polishing, second ion polishing and third ion polishing increase, and the voltage of the third ion polishing is higher than that of the fourth ion polishing.

[0029] Preferably, the voltage of the first ion polishing is 2 - 4 kV. For example, it can be 2 kV, 3 kV or 4 kV, etc.; the current is 0.2 - 0.4 mA. For example, it can be 0.2 mA, 0.3 mA or 0.4 mA, etc.; the time is 1 - 5 min. For example, it can be 1 min, 2 min, 3 min, 4 min or 5 min, etc., but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0030] Preferably, the voltage of the second ion polishing is 4 - 6 kV. For example, it can be 4 kV, 5 kV or 6 kV, etc.; the current is 0.2 - 0.4 mA. For example, it can be 0.2 mA, 0.3 mA or 0.4 mA, etc.; the time is 1 - 5 min. For example, it can be 1 min, 2 min, 3 min, 4 min or 5 min, etc., but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0031] Preferably, the voltage of the third ion polishing is 6 - 8 kV. For example, it can be 6 kV, 7 kV or 8 kV, etc.; the current is 0.2 - 0.4 mA. For example, it can be 0.2 mA, 0.3 mA or 0.4 mA, etc.; the time is 50 - 80 min. For example, it can be 50 min, 60 min, 70 min or 80 min, etc., but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0032] Preferably, the voltage of the fourth ion polishing is 4 - 6 kV. For example, it can be 4 kV, 5 kV or 6 kV, etc.; the current is 0.2 - 0.4 mA. For example, it can be 0.2 mA, 0.3 mA or 0.4 mA, etc.; the time is 20 - 40 min. For example, it can be 20 min, 25 min, 30 min, 35 min or 40 min, etc., but it is not limited to the listed values, and other unlisted values within this value range are equally applicable.

[0033] In the present invention, when the first ion polishing, the second ion polishing, the third ion polishing, and the fourth ion polishing meet the above - defined conditions, it is more conducive to obtaining a sample with a smooth and flat surface and no obvious scratches.

[0034] Preferably, the voltage difference between the first ion polishing and the second ion polishing is 1 - 3 kV. For example, it can be 1 kV, 2 kV, 3 kV, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0035] Preferably, the voltage difference between the second ion polishing and the third ion polishing is 1 - 3 kV. For example, it can be 1 kV, 2 kV, 3 kV, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0036] Preferably, the voltage difference between the third ion polishing and the fourth ion polishing is 1 - 3 kV. For example, it can be 1 kV, 2 kV, 3 kV, etc., but it is not limited to the listed values, and other unlisted values within this numerical range are equally applicable.

[0037] In the present invention, when the voltage differences between the first ion polishing, the second ion polishing, the third ion polishing, and the fourth ion polishing meet the above conditions, it is more conducive to obtaining a sample with a smooth and flat surface and no obvious scratches.

[0038] The numerical range described in the present invention not only includes the above - listed point values, but also includes any point values between the above - mentioned numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] Through technical means such as grinding, mechanical polishing, and ion polishing, the surface of the sample to be tested prepared by the present invention is smooth and flat, without obvious scratches. When performing EBSD detection, the diffraction Kikuchi bands of the sample are clear, with a high resolution, high stability, and at the same time, the calibration rate of the sample is relatively high, reaching 90% or more, the results are accurate, meeting general requirements, and the effect is good.

[0041] Through ion polishing, the present invention can remove the stress layer on the surface of the sample, making the diffraction pattern obvious. During the ion polishing process, the voltage first increases and then decreases, which can polish the surface of the sample more smoothly and make the polishing process more stable. Detailed implementation mode

[0042] The technical solution of the present invention will be further described below through specific embodiments. For the convenience of understanding the present invention, the following embodiments are listed. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0043] Example 1

[0044] This embodiment provides a method for preparing a sample for EBSD detection of a nickel-platinum sputtering target, which specifically includes the following steps:

[0045] (1) Use wire cutting technology to cut the nickel-platinum sputtering target into nickel-platinum target blocks of 10×10×10 mm, wherein the purity of the nickel-platinum sputtering target is 99.99%; in the nickel-platinum sputtering target, the mass ratio of nickel element to platinum element is 70:30.

[0046] (2) Grind the nickel-platinum target blocks successively with 240# and 1000# SiO 2 sandpaper, then mechanically polish with a diamond suspension with a particle size D50 of 3 μm for 5 min, then mechanically polish with an alumina suspension with a particle size D50 of 0.3 μm for 10 min, and then mechanically polish with a silica suspension with a particle size D50 of 50 nm for 30 min. Finally, perform argon ion polishing treatment, and the steps are as follows: ① First ion polishing: voltage 3 kV, current 0.3 mA, time 2 min; ② Second ion polishing: voltage 5 kV, current 0.3 mA, time 2 min; ③ Third ion polishing: voltage 7 kV, current 0.3 mA, time 60 min; ④ Fourth ion polishing: voltage 5 kV, current 0.3 mA, time 30 min. After the argon ion polishing is completed, the sample to be measured is obtained.

[0047] Example 2

[0048] This embodiment provides a method for preparing a sample for EBSD detection of a nickel-platinum sputtering target, which specifically includes the following steps:

[0049] (1) Use wire cutting technology to cut the nickel-platinum sputtering target into nickel-platinum target blocks of 10×10×10 mm, wherein the purity of the nickel-platinum sputtering target is 99.99%; in the nickel-platinum sputtering target, the mass ratio of nickel element to platinum element is 85:15.

[0050] (2) Grind the nickel-platinum target blocks successively with 240# and 1000# SiO 2The nickel-platinum target block was ground with sandpaper, then mechanically polished with a diamond suspension with a D50 particle size of 4 μm for 5 min, then mechanically polished with an alumina suspension with a D50 particle size of 0.4 μm for 15 min, and then mechanically polished with a silica suspension with a D50 particle size of 60 nm for 20 min. Finally, argon ion polishing was used for treatment, and the steps were as follows: ① First ion polishing: voltage 4 kV, current 0.3 mA, time 3 min; ② Second ion polishing: voltage 6 kV, current 0.3 mA, time 3 min; ③ Third ion polishing: voltage 8 kV, current 0.3 mA, time 70 min; ④ Fourth ion polishing: voltage 6 kV, current 0.3 mA, time 40 min. After ion polishing was completed, the sample to be measured was obtained.

[0051] Example 3

[0052] This example provides a sample preparation method for EBSD detection of nickel-platinum sputtering targets, which specifically includes the following steps:

[0053] (1) The nickel-platinum sputtering target was cut into a nickel-platinum target block of 10×10×10 mm using wire cutting technology, where the purity of the nickel-platinum sputtering target was 99.99%; in the nickel-platinum sputtering target, the mass ratio of nickel element to platinum element was 55:45.

[0054] (2) The nickel-platinum target block was ground with 240# and 1000# SiO 2 sandpaper, then mechanically polished with a diamond suspension with a D50 particle size of 2 μm for 8 min, then mechanically polished with an alumina suspension with a D50 particle size of 0.2 μm for 20 min, and then mechanically polished with a silica suspension with a D50 particle size of 40 nm for 40 min. Finally, argon ion polishing was used for treatment, and the steps were as follows: ① First ion polishing: voltage 2 kV, current 0.3 mA, time 2 min; ② Second ion polishing: voltage 5 kV, current 0.3 mA, time 2 min; ③ Third ion polishing: voltage 8 kV, current 0.3 mA, time 60 min; ④ Fourth ion polishing: voltage 5 kV, current 0.3 mA, time 30 min. After ion polishing was completed, the sample to be measured was obtained.

[0055] Example 4

[0056] The difference between this example and Example 1 is that in the steps of argon ion polishing, the voltage of the second ion polishing was adjusted to 7 kV; the voltage of the third ion polishing was adjusted to 11 kV; the voltage of the fourth ion polishing was adjusted to 7 kV.

[0057] The remaining parameters were the same as those in Example 1.

[0058] Example 5

[0059] The difference between this embodiment and Embodiment 1 lies in that in the argon ion polishing step, the voltage of the second ion polishing is adjusted to 3.5 kV; the voltage of the third ion polishing is adjusted to 4 kV; the voltage of the fourth ion polishing is adjusted to 3.5 kV.

[0060] The remaining parameters are the same as those in Embodiment 1.

[0061] Comparative Example 1

[0062] The difference between this comparative example and Embodiment 1 is that argon ion polishing is not performed.

[0063] The remaining parameters are the same as those in Embodiment 1.

[0064] Comparative Example 2

[0065] The difference between this comparative example and Embodiment 1 is that the argon ion polishing steps are as follows: voltage 7 kV, current 0.3 mA, time 94 min.

[0066] The remaining parameters are the same as those in Embodiment 1.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Embodiment 1 is that in the argon ion polishing step, the fourth ion polishing step is omitted.

[0069] The remaining parameters are the same as those in Embodiment 1.

[0070] Comparative Example 4

[0071] The difference between this comparative example and Embodiment 1 is that in the argon ion polishing step, the third ion polishing, the second ion polishing, the first ion polishing, and the fourth ion polishing are performed in sequence.

[0072] The remaining parameters are the same as those in Embodiment 1.

[0073] Testing

[0074] The test samples provided in the above embodiments and comparative examples are subjected to EBSD testing. The test conditions are as follows: magnification is 300, scanning step size is 2 μm, working distance is 15 mm, and working voltage is 30 kV. The measured calibration rate is shown in Table 1.

[0075] Table 1

[0076]

[0077]

[0078] Analysis:

[0079] As can be seen from Examples 1-3, for the test samples prepared by the method of the present invention, when subjected to EBSD detection, the samples have a high calibration rate.

[0080] As can be seen from Example 1 and Examples 4-5, in the step of argon ion polishing, when the voltage of ion polishing is too high or too low, or the voltage difference between two adjacent ion polishings is too large or too small, the calibration rate of the sample will decrease.

[0081] As can be seen from Example 1 and Comparative Example 1, if the step of argon ion polishing is not carried out, the sample is not sufficiently polished, resulting in a decrease in the calibration rate of the sample.

[0082] As can be seen from Example 1 and Comparative Example 2, if the voltage remains unchanged during the argon ion polishing process, the calibration rate of the sample will decrease.

[0083] As can be seen from Example 1 and Comparative Example 3, in the step of argon ion polishing, if the fourth ion polishing is not carried out, that is, the voltage shows a trend of increasing in gradient during the argon ion polishing process, the calibration rate of the sample will decrease.

[0084] As can be seen from Example 1 and Comparative Example 4, in the step of argon ion polishing, if the voltage shows a trend of first decreasing in gradient and then increasing, the calibration rate of the sample will decrease.

[0085] The above are only the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing a sample for EBSD detection of a nickel-platinum sputtering target, characterized in that: The sample preparation method comprises: (1) cutting a nickel-platinum sputtering target to obtain a nickel-platinum target block; (2) grinding, mechanical polishing and ion polishing the nickel-platinum target block in sequence to obtain a sample to be tested; Wherein, during the ion polishing process, the voltage is first increased and then decreased.

2. The sample preparation method according to claim 1, characterized in that: The purity of the nickel-platinum sputtering target is ≥99.99%; Preferably, in the nickel-platinum sputtering target, the mass ratio of nickel element to platinum element is (40-97):(3-60).

3. The sample preparation method according to claim 1 or 2, characterized in that: The cutting method in step (1) includes wire cutting; Preferably, the size of the nickel-platinum target block is (8-15) mm×(8-15) mm×(8-15) mm.

4. The sample preparation method according to any one of claims 1 to 3, characterized in that: The grinding includes a first grinding and a second grinding performed sequentially; Preferably, the first grinding uses 200#-300# SiO2 sandpaper; Preferably, the second grinding uses 900#-1100# SiO2 sandpaper.

5. The sample preparation method according to any one of claims 1 to 4, characterized in that: The mechanical polishing includes a first mechanical polishing, a second mechanical polishing and a third mechanical polishing performed sequentially; Preferably, the first mechanical polishing uses a diamond suspension; the particle size D50 of the diamond particles in the diamond suspension is 2-5 μm; Preferably, the first mechanical polishing time is 5-10 min; Preferably, the second mechanical polishing uses an aluminum oxide suspension; the particle size D50 of the aluminum oxide particles in the aluminum oxide suspension is 0.1-0.5 μm; Preferably, the second mechanical polishing time is 10-20 min; Preferably, the third mechanical polishing uses a silicon oxide suspension, and the particle size D50 of the silicon oxide particles in the silicon oxide suspension is 40-80 nm; Preferably, the third mechanical polishing takes 20-50 minutes.

6. The sample preparation method according to any one of claims 1 to 5, characterized in that: The ions used in the ion polishing include argon ions.

7. The sample preparation method according to any one of claims 1 to 6, characterized in that: The ion polishing includes first ion polishing, second ion polishing, third ion polishing and fourth ion polishing performed in sequence; the voltage gradients of the first ion polishing, the second ion polishing and the third ion polishing increase, and the voltage of the third ion polishing is higher than the voltage of the fourth ion polishing.

8. The sample preparation method according to claim 7, characterized in that: The voltage of the first ion polishing is 2-4 kV, the current is 0.2-0.4 mA, and the time is 1-5 min; Preferably, the voltage of the second ion polishing is 4-6 kV, the current is 0.2-0.4 mA, and the time is 1-5 min; Preferably, the voltage of the third ion polishing is 6-8 kV, the current is 0.2-0.4 mA, and the time is 50-80 min; Preferably, the fourth ion polishing has a voltage of 4-6 kV, a current of 0.2-0.4 mA, and a time of 20-40 min.

9. The sample preparation method according to claim 7 or 8, characterized in that: The voltage difference between the first ion polishing and the second ion polishing is 1-3 kV; Preferably, the voltage difference between the second ion polishing and the third ion polishing is 1-3 kV.

10. The sample preparation method according to any one of claims 7 to 9, characterized in that: The voltage difference between the third ion polishing and the fourth ion polishing is 1-3 kV.

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