Sem detection method of a diamond sample

Abstract

The application discloses a kind of SEM detection methods of diamond sample, including the following steps: diamond sample is placed in microwave plasma chemical vapor deposition equipment, and at first preset temperature, using hydrogen plasma gas is carried out surface treatment to diamond sample first preset length of time, to form hydrogen ion suspension bond on diamond sample surface, obtain intermediate sample;First preset temperature is between 200 DEG C-500 DEG C;After intermediate sample is immersed in metal ion solution for second preset time, it is taken out, and obtains the sample to be detected;Using conductive adhesive is bonded to the sample to be detected on test base, and using SEM equipment carries out surface detection;The sample to be detected is cleaned multiple times using ultrasonic, to remove the metal ion on the surface of the sample to be detected, and reduction obtains intermediate sample.The method in the application can clearly collect the SEM microstructure diagram of diamond sample, and the implementation cost is lower.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a SEM detection method for diamond samples. Background Technology

[0002] Diamond possesses excellent physical, chemical, and electrical properties, including high hardness, high thermal conductivity, resistance to acid and alkali corrosion, and an ultra-wide bandgap, making it valuable in fields such as machinery, semiconductors, and jewelry. However, natural diamonds are scarce and expensive, and suffer from issues such as uneven quality and small size. Therefore, to obtain large-area, stable, uniform, low-cost, and high-quality diamonds, it is essential to develop artificial diamond synthesis technology.

[0003] In commonly used diamond synthesis processes, the uniformity of the grown diamond is greatly affected by process conditions. For example, in the commonly used microwave plasma chemical vapor deposition (MPCVD) method, the uniformity of the grown diamond largely depends on the collimation of the plasma sphere. This collimation is influenced by various factors such as the distribution of the microwave field, disturbances from the mixed growth gas, and the sample stage and cavity structure. Therefore, even the best MPCVD equipment cannot completely prevent the tilting and offset of the plasma sphere, leading to uneven growth rate and thickness. To promptly eliminate low-quality diamonds and prevent them from affecting the performance of the resulting semiconductors in subsequent semiconductor fabrication processes, a highly accurate quality inspection of diamonds without compromising their suitability for use in subsequent semiconductor device fabrication has become a pressing issue for those skilled in the art. Summary of the Invention

[0004] Therefore, in order to solve the above-mentioned problems in the prior art, the present invention provides a SEM detection method for diamond samples.

[0005] The SEM detection method for diamond samples provided by this invention includes the following steps:

[0006] A diamond sample is placed in a microwave plasma chemical vapor deposition apparatus and surface-treated with hydrogen plasma gas at a first preset temperature for a first preset time to form hydrogen ion dangling bonds on the surface of the diamond sample to obtain an intermediate sample; the first preset temperature is between 200℃ and 500℃.

[0007] The intermediate sample is immersed in the metal ion solution for a second preset time and then removed to obtain the sample to be tested.

[0008] The sample to be tested was bonded to the test base using a conductive adhesive, and the surface was inspected using an SEM device.

[0009] The sample to be tested was subjected to multiple ultrasonic cleanings to remove metal ions from the surface of the gold sample and reduce it to obtain an intermediate sample.

[0010] In an optional embodiment, after performing multiple ultrasonic cleanings on the sample to be tested to remove metal ions from the surface of the sample and reducing it to obtain an intermediate sample, the following steps are further included:

[0011] The intermediate sample was heated in an oxygen atmosphere to remove the hydrogen ion dangling bonds on the surface of the intermediate sample and reduce it to obtain a diamond sample.

[0012] In an optional embodiment, the first preset time is between 20 min and 40 min.

[0013] In an optional embodiment, the metal ion is any one of gold ions, copper ions, and iron ions; the second preset time is between 3 min and 10 min.

[0014] In an optional embodiment, the cleaning solution for ultrasonic cleaning is deionized water, and the number of ultrasonic cleaning cycles is between 3 and 5.

[0015] The technical solution provided by this invention has the following advantages:

[0016] 1. The SEM detection method for diamond samples provided by the present invention treats the surface of the diamond sample with hydrogen plasma gas to form hydrogen ion dangling bonds on the surface of the diamond sample, which can improve its conductivity to a certain extent and facilitate the adhesion of metal ions. After a second preset time in the metal ion solution, the sample is taken out to achieve a comprehensive improvement in the conductivity of the diamond sample. Then, a conductive adhesive is used to bond the sample to the test base so that a clear surface image can be acquired by the SEM equipment, and the detection can be accurately completed.

[0017] By setting the first temperature for surface treatment with hydrogen plasma gas to a relatively low range (below the temperature commonly used in the field for hydrogen plasma surface treatment of diamond) of 200℃-500℃, it is possible to prevent the hydrogen plasma gas from etching the surface of the diamond sample during the treatment process, prevent the implementation of this detection method from affecting the quality of the diamond sample, and thus prevent the diamond sample from being unable to enter the semiconductor device fabrication process, thus avoiding the problem of wasting resources.

[0018] By forming hydrogen ion dangling bonds on the surface of the diamond sample and then immersing it in a metal ion solution (instead of sticking a conductive layer or growing a conductive layer using processes such as spraying or spin coating), the conductivity of the diamond sample is improved. This method allows for the removal of metal ions through multiple ultrasonic cleanings after the surface inspection step of the SEM equipment, further reducing the impact of the method on the diamond sample's entry into the semiconductor device fabrication process. Moreover, the removal is less difficult and less costly.

[0019] 2. The SEM detection method for diamond samples provided by the present invention further removes the hydrogen ion dangling bonds on the surface of the diamond sample after removing the metal ions, thereby reducing the initial diamond sample. This method can further reduce the impact of the detection method on the diamond sample entering the semiconductor device fabrication process, and the reduction is less difficult and less costly. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A flowchart of a method for SEM detection of diamond samples provided in an embodiment of the present invention;

[0022] Figure 2 The image shows the SEM microstructure of a diamond sample when the detection method described in this embodiment of the invention was not used.

[0023] Figure 3 SEM microstructure of diamond samples when the detection method in this embodiment of the invention is used. Detailed Implementation

[0024] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] Figure 1 A flowchart of a SEM detection method for diamond samples provided in this embodiment is shown below. Figure 1 As shown, the method includes the following steps:

[0027] Step S10: Place the diamond sample in a microwave plasma chemical vapor deposition apparatus and perform surface treatment on the diamond sample with hydrogen plasma gas at a first preset temperature for a first preset time length to form hydrogen ion dangling bonds on the surface of the diamond sample, thereby obtaining an intermediate sample.

[0028] In this embodiment, the first preset temperature is a temperature that is lower than the temperature commonly used in existing diamond hydrogen terminal processing (generally 700℃-1000℃). Specifically, the first preset temperature is between 200℃ and 500℃.

[0029] Specifically, the first preset time is between 20 and 40 minutes.

[0030] In addition, the hydrogen flow rate in the plasma chemical vapor deposition equipment can be set between 100 sccm and 600 sccm, the chamber pressure between 50 mbar and 200 mbar, and the power between 1000 W and 3000 W.

[0031] Step S20: Immerse the intermediate sample in the metal ion solution for a second preset time and then remove it to obtain the sample to be tested.

[0032] In this embodiment, the metal ion solution can be any one of gold ion solution, copper ion solution, and iron ion solution. The second time can be between 3 min and 10 min.

[0033] In this embodiment, the sample to be tested after being processed in step S20 needs to be dried before proceeding to step S30. Specifically, the sample to be tested can be dried by air drying, baking, or blowing.

[0034] Step S30: Use conductive adhesive to bond the sample to be tested to the test base, and use SEM equipment to perform surface inspection.

[0035] Step S40: Perform multiple ultrasonic cleanings on the sample to be tested to remove metal ions from the surface of the gold sample and reduce it to obtain an intermediate sample.

[0036] Specifically, deionized water can be used as the cleaning solution for ultrasonic cleaning of the sample to be tested. The number of ultrasonic cleanings can be between 3 and 5, and the time for each ultrasonic cleaning is between 10 and 20 minutes. For example, four ultrasonic cleanings can be performed, with each cleaning lasting 15 minutes.

[0037] like Figure 2 and Figure 3 The figures show the microstructures of diamond samples obtained by direct SEM analysis without using the detection method described in this embodiment, and the microstructures obtained using the detection method described in this embodiment. Clearly, the microstructures obtained using the detection method described in this embodiment are superior. Figure 3 The image is clearer.

[0038] In summary, the SEM detection method for diamond samples in this embodiment treats the surface of the diamond sample with hydrogen plasma gas to form hydrogen ion dangling bonds that improve conductivity to a certain extent and facilitate the adhesion of metal ions. After immersing the sample in a metal ion solution for a second preset time, the conductivity of the diamond sample is comprehensively improved. Finally, a conductive adhesive is used to bond the sample to the test base, allowing the SEM equipment to acquire a clear surface image and accurately complete the detection.

[0039] By setting the first temperature for surface treatment with hydrogen plasma gas to a relatively low range (below the temperature commonly used in the field for hydrogen plasma surface treatment of diamond) of 200℃-500℃, it is possible to prevent the hydrogen plasma gas from etching the surface of the diamond sample during the treatment process, prevent the implementation of this detection method from affecting the quality of the diamond sample, and thus prevent the diamond sample from being unable to enter the semiconductor device fabrication process, thus avoiding the problem of wasting resources.

[0040] By forming hydrogen ion dangling bonds on the surface of the diamond sample and then immersing it in a metal ion solution (instead of sticking a conductive layer or growing a conductive layer using processes such as spraying or spin coating), the conductivity of the diamond sample is improved. This method allows for the removal of metal ions through multiple ultrasonic cleanings after the surface inspection step of the SEM equipment, further reducing the impact of the method on the diamond sample's entry into the semiconductor device fabrication process. Moreover, the removal is less difficult and less costly.

[0041] Although hydrogen termination treatment is required on the surface of diamond in most semiconductor fabrication processes, there are also situations where hydrogen-terminated diamond is not conducive to fabrication, such as in heat sink packaging. Therefore, in a specific embodiment of this example, in addition to the above steps S10-S40, the following steps are included after step S40:

[0042] Step S50: The intermediate sample is heated in an oxygen atmosphere to remove the hydrogen ion dangling bonds on the surface of the intermediate sample and reduce it to obtain the diamond sample.

[0043] Specifically, the intermediate sample can be heated in an oxygen atmosphere at 200℃-300℃ to reduce it to obtain a diamond sample. The heating time can be between 20min and 30min.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A SEM detection method for diamond samples, characterized in that, Includes the following steps: The diamond sample is placed in a microwave plasma chemical vapor deposition apparatus, and the surface of the diamond sample is treated with hydrogen plasma gas at a first preset temperature for a first preset time to form hydrogen ion dangling bonds on the surface of the diamond sample, thereby obtaining an intermediate sample; the first preset temperature is between 200℃ and 500℃. The intermediate sample is immersed in a metal ion solution for a second preset time and then removed to obtain the sample to be tested; the metal ion is any one of gold ion, copper ion and iron ion; the second preset time is between 3 min and 10 min. The sample to be tested was bonded to the test base using a conductive adhesive, and the surface was inspected using an SEM device. The sample to be tested is subjected to multiple ultrasonic cleanings to remove metal ions from its surface, thereby reducing it to obtain the intermediate sample.

2. The SEM detection method for diamond samples according to claim 1, characterized in that, After the step of performing multiple ultrasonic cleanings on the sample to be tested to remove metal ions from the surface of the sample and reducing it to obtain the intermediate sample, the method further includes the following steps: The intermediate sample was heated in an oxygen atmosphere to remove the hydrogen ion dangling bonds on the surface of the intermediate sample, thereby reducing it to obtain the diamond sample.

3. The SEM detection method for diamond samples according to claim 1 or 2, characterized in that, The first preset time is between 20 min and 40 min.

4. The SEM detection method for diamond samples according to claim 3, characterized in that, The ultrasonic cleaning solution is deionized water, and the ultrasonic cleaning is performed 3 to 5 times.

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