A preparation method of Y2O3-BZO composite coating suitable for etching machine parts

Abstract

The present invention provides a method for preparing a Y2O3-BZO composite coating applicable to components of an etching machine, comprising the following steps: S1. Take a substrate, clean it, dry it, and perform secondary cleaning with a UV light cleaning machine; S2. Place the substrate in step S1 into a magnetron sputtering coating machine, heat it while pumping vacuum, and after reaching the base vacuum, introduce argon gas and perform pre-sputtering on the Y2O3 and BZO targets; S3. After the pre-sputtering is completed, open the baffle, adjust the chamber pressure, and start the formal sputtering. The formal sputtering adopts an alternating sputtering form to sputter the Y2O3 and BZO targets respectively to form a stacked composite coating. After the sputtering is completed, take out the substrate; S4. Perform vacuum annealing on the substrate in step S3 and let it cool naturally to obtain the Y2O3-BZO stacked composite coating. The composite coating is formed into a stacked composite coating by adopting an alternating sputtering form, has good etching resistance, can greatly improve the service life of the etching machine, and reduce the pollution caused to the wafer.

Description

Technical Field

[0001] The invention belongs to the technical field of etcher and semiconductor chip surface coating, and specifically relates to a method for preparing a Y2O3-BZO composite coating which has excellent plasma etching resistance and is suitable for etcher parts. Background Art

[0002] Semiconductor materials are the cornerstone of the modern electronic information industry. According to statistics from the World Semiconductor Trade Statistics Association (WSTS), the market size of the semiconductor industry has reached US$500 billion by 2023. In the semiconductor industry, wafer manufacturing is the most important step. During the manufacturing process, fluorine-containing plasma is usually used to etch the wafer to achieve the purpose of obtaining nanoscale integrated circuits.

[0003] The mainstream etching-resistant coatings currently used in etchers are Y2O3 and Al2O3. While fluorine-containing plasma etches wafers, its physical impact and chemical reaction will also cause significant corrosion to the chamber of the etcher. This corrosion will not only reduce the service life of the equipment, but also the byproducts produced during the corrosion process may volatilize and fall off, and then form impurity particles in the chamber of the etcher, causing contamination to the wafer.

[0004] In order to extend the service life of the machine and improve the etching yield of the wafer, it is urgent to develop a material with excellent etching resistance. Summary of the invention

[0005] In view of this, the present invention provides a method for preparing a Y2O3-BZO composite coating with excellent plasma etching resistance and suitable for etching machine parts. A stacked coating of Y2O3 and BZO is prepared by dual-target alternating magnetron sputtering to improve the etching resistance of the material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a Y2O3-BZO composite coating suitable for etching machine parts comprises the following steps:

[0008] S1. Take the substrate for cleaning, drying, and secondary cleaning with UV light cleaning machine;

[0009] S2, placing the substrate in step S1 in a magnetron sputtering coating machine, evacuating and heating the substrate, introducing argon gas after reaching the background vacuum, and pre-sputtering the Y2O3 and BZO targets;

[0010] S3. After the pre-sputtering is completed, the baffle is opened, the chamber pressure is adjusted, and the formal sputtering begins. The formal sputtering adopts an alternating sputtering mode to sputter the Y2O3 and BZO targets respectively to form a stacked composite coating. After the sputtering is completed, the substrate is taken out;

[0011] S4. The substrate in step S3 is subjected to vacuum annealing and naturally cooled to obtain a Y2O3-BZO stacked composite coating.

[0012] Furthermore, in step S1, the substrate is ultrasonically cleaned with acetone, alcohol and deionized water for 10 to 20 minutes in sequence, and then blown dry with N2.

[0013] Furthermore, the ultrasonic power during the cleaning is 160W-200W, the wavelength of ultraviolet light emitted by the UV light cleaning machine is 185nm, and the cleaning time is 10-30min.

[0014] Furthermore, the background vacuum in step S2 is 1×10 -3 Pa, the heating temperature is 250~350℃, and the argon flow rate is 40~80sccm.

[0015] Furthermore, during pre-sputtering in step S2, the sputtering power of the Y2O3 target is 160-200 W, and the sputtering power of the BZO target is 40-80 W; the pre-sputtering time is 5-15 min.

[0016] Furthermore, in step S3, during the formal sputtering, the chamber pressure is 0.2-0.6 Pa, the formal sputtering power is the same as that of the pre-sputtering, and the formal sputtering time is 200-300 min.

[0017] Furthermore, the number of stacked composite coating layers is 4 to 24, and the thickness is 400 to 600 nm.

[0018] Furthermore, the vacuum annealing conditions in step S4 are: a heating rate of 9-11°C / min, a temperature of 800-1000°C, a holding time of 1-3h, and a vacuum degree of 100-300Pa.

[0019] In some specific embodiments, preferably, the Y2O3 target has a diameter of 76.2 mm, a thickness of 3 mm, and is bound to a 2 mm copper backing plate; the BZO target has a size of 60 mm, a thickness of 3 mm, and is bound to a 2 mm copper backing plate.

[0020] Application of the Y2O3-BZO stacked composite coating prepared by the above method in etching equipment.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention sputters Y2O3 and BZO targets respectively in the form of alternating sputtering, and finally prepares a composite coating with stacked layers by setting different sputtering powers and annealing parameters. The composite coating has good etching resistance, and the etching rate is between 0.67 and 1.38 mm / min, which is significantly higher than that of conventional etching-resistant coatings (the conventional Al2O3 etching rate is 15.8 mm / min). It can play a good protective role on the etcher, prolong its life, and reduce the pollution caused to the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the stacked Y2O3-BZO stacked composite coating prepared in the present invention.

[0024] Figure 2 X-ray diffraction patterns of the coatings prepared in Example 3 and Comparative Examples 1-5. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand the present invention more clearly.

[0026] Sources and physical and chemical parameters of key test materials:

[0027] Y2O3 target and BZO (BaZrO3) target were purchased from Zhongnuo New Materials (Beijing) Technology Co., Ltd. with a purity of 99.99%.

[0028] Example 1

[0029] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance, and the specific preparation method includes the following steps:

[0030] S1. The P-type Si substrate was ultrasonically treated with acetone, alcohol and deionized water at 180W for 15 minutes, and then dried with N2. The substrate surface was then cleaned for 20 minutes using a UV light cleaning machine with a wavelength of 185nm.

[0031] S2. Place the substrate in a magnetron sputtering coating machine, select Y2O3 and BZO ceramic targets, and heat the substrate to 300°C while evacuating the vacuum to reach a background vacuum of 1×10 -3 After 1 Pa, Ar with a flow rate of 160 sccm was introduced, the chamber pressure was adjusted to 2 Pa, the power of Y2O3 and BZO targets were adjusted to 180 W and 60 W respectively, and the targets were pre-sputtered for 10 min.

[0032] S3. After sputtering, open the baffle, adjust the gas flow rate to 60sccm, the chamber pressure to 0.4Pa, keep the power unchanged, and sputter the Y2O3 and BZO targets alternately. The sputtering time for each target is 60min, and the number of coating stacking layers is 4. After sputtering for 240min, turn off the machine and take out the substrate.

[0033] S4. The prepared coating is placed in a tubular furnace and heated to 900°C at 9°C / min for 2h vacuum annealing. After the treatment, the coating is cooled naturally to obtain a Y2O3-BZO stacked composite coating.

[0034] Example 2

[0035] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that the sputtering time of each target material in step S3 is 40 minutes, and the number of stacked layers of the coating is 6.

[0036] Example 3

[0037] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that the sputtering time of each target material in step S3 is 20 minutes, and the number of stacked layers of the coating is 12.

[0038] Example 4

[0039] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that the sputtering time of each target material in step S3 is 10 minutes, and the number of stacked layers of the coating is 24.

[0040] Example 5

[0041] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance, and the specific preparation method includes the following steps:

[0042] S1. The P-type Si substrate was ultrasonically treated with acetone, alcohol and deionized water at 160W for 20 minutes, and then dried with N2. The substrate surface was then cleaned for 10 minutes using a UV light cleaning machine with a wavelength of 185nm.

[0043] S2. Place the substrate in a magnetron sputtering coating machine, select Y2O3 and BZO ceramic targets, and heat the substrate to 250°C while evacuating the vacuum to reach a background vacuum of 1×10 -3After 150 sccm of Ar was introduced, the chamber pressure was adjusted to 2 Pa, the power of Y2O3 and BZO targets were adjusted to 160 W and 80 W respectively, and the targets were pre-sputtered for 15 min.

[0044] S3. After sputtering, open the baffle, adjust the gas flow rate to 40sccm, the chamber pressure to 0.2Pa, keep the power unchanged, and sputter the Y2O3 and BZO targets alternately. The sputtering time of each target is 60min, and the number of coating stacking layers is 4. After sputtering for 240min, turn off the machine and take out the substrate.

[0045] S4. The prepared coating is placed in a tubular furnace and heated to 800°C at a temperature of 10°C / min for 3h vacuum annealing. After the treatment, the coating is cooled naturally to obtain a Y2O3-BZO stacked composite coating.

[0046] Example 6

[0047] This embodiment provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance, and the specific preparation method includes the following steps:

[0048] S1. The P-type Si substrate was ultrasonically treated with acetone, alcohol and deionized water at 200W for 10 minutes, and then dried with N2. The substrate surface was then cleaned for 30 minutes using a UV light cleaning machine with a wavelength of 185nm.

[0049] S2. Place the substrate in a magnetron sputtering coating machine, select Y2O3 and BZO ceramic targets, and heat the substrate to 300°C while evacuating the vacuum to reach a background vacuum of 1×10 -3 After Pa, Ar with a flow rate of 160 sccm was introduced, the chamber pressure was adjusted to 2Pa, the power of Y2O3 and BZO targets were adjusted to 200 W and 40 W respectively, and the targets were pre-sputtered for 5 minutes.

[0050] S3. After sputtering, open the baffle, adjust the gas flow rate to 80sccm, the chamber pressure to 0.6Pa, keep the power unchanged, and sputter the Y2O3 and BZO targets alternately. The sputtering time of each target is 60min, and the number of coating stacking layers is 4. After sputtering for 240min, turn off the machine and take out the substrate.

[0051] S4. The prepared coating is placed in a tubular furnace and heated to 1000°C at 11°C / min for 1h vacuum annealing. After the treatment, the coating is cooled naturally to obtain a Y2O3-BZO stacked composite coating.

[0052] Comparative Example 1

[0053] This comparative example provides a coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that: the target material only uses Y2O3 ceramic target material for sputtering, and the rest remains unchanged.

[0054] Comparative Example 2

[0055] This comparative example uses aluminum oxide commonly used in etchers as an etch-resistant coating, cuts commercial Al2O3 wafers to obtain Al2O3 wafers with a size of 1×1 cm, and then further verifies their performance.

[0056] Comparative Example 3

[0057] This comparative example provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that: in step S3, Y2O3 and BZO targets are sputtered simultaneously, and the rest remain unchanged.

[0058] Comparative Example 4

[0059] This comparative example provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that the sputtering power of the BZO target in steps S2 and S3 is 90 W, and the rest remain unchanged.

[0060] Comparative Example 5

[0061] This comparative example provides a Y2O3-BZO stacked composite coating with excellent plasma etching resistance. The specific preparation method is basically the same as that of Example 1, except that the sputtering power of the BZO target in steps S2 and S3 is 30 W, and the rest remain unchanged.

[0062] Furthermore, in order to understand the properties of the various coatings prepared above, the following tests were also conducted:

[0063] Test steps: After annealing, each coating is half-masked with high-temperature tape and placed in the ICP inductively coupled plasma etching equipment. After vacuuming, the inside of the etcher chamber is cleaned with a mixed gas of Ar and O2 to remove impurities and etching residues in the chamber. After cleaning, CF4 and O2 are introduced, the coil power is adjusted to 800W, the bias power is 100W, and the chamber pressure is 15mTorr. The film is etched with a gas flow ratio of 25sccm:5sccm and an etching time of 60min. After etching, the film is taken out, the high-temperature tape is washed off with acetone, and the sample etching rate is tested with a step profiler. The specific test results are shown in Table 1.

[0064] Table 1 Etching rate results of each coating sample

[0065]

[0066] It can be seen from Table 1 that the etching rates of the composite coatings provided in Examples 1-6 are between 0.67 and 1.38 mm / min, which are all higher than the coatings in the comparative examples; and by comparison, it can be found that the different number of stacked layers has a certain influence on the etching rate. In general, the etching rate shows a trend of first decreasing and then increasing with the increase in the number of layers. Among them, the 12 layers in Example 3 have the highest etching resistance, followed by the 24 layers in Example 4, followed by Examples 1 and 2 (the two have equivalent effects), and the worst are Examples 5 and 6 (the two have equivalent effects); while Examples 1, 5, and 6 all have 4 layers, but Examples 5 and 6 have slightly lower etching resistance, which may be due to the adjustment of the sputtering pressure and gas flow rate, resulting in an increase in porosity and a slight decrease in etching resistance.

[0067] Compared with Comparative Example 1, the addition of BZO target in the present application leads to better etching resistance. This may be because the addition of BZO causes the lattice distortion of Y2O3, which reduces the oxygen vacancies in Y2O3 and suppresses the high diffusion rate of oxygen ions, so that the etching is carried out on the oxygen-rich surface. The YO bond binding energy (719.6 KJ / mol) is higher than that of YF (605 KJ / mol), and has a higher ability to resist physical sputtering, so the etching rate is lower than that of the pure Y2O3 film.

[0068] Compared with Comparative Example 3, the film prepared in Comparative Example 3 is sputtered by two targets at the same time. The two substances may react in the chamber of the magnetron sputtering instrument to generate a certain compound, and the compound has not crystallized, thus causing the etching resistance to further decrease. However, the present application adopts the form of stacking multiple layers to make the coating more etch-resistant, because when the alternating sputtering stack is used, not only the Y2O3 film is etched, but also the BZO film underneath. 2+ Will be with F - BaF2 is formed. The sublimation temperature of BaF2 is 2260℃, which is higher than the sublimation temperature of YF3 (2230℃). It covers the surface of the film and provides secondary protection for the coating below, thus further improving the performance.

[0069] Compared with Comparative Examples 4 and 5, the performance of Comparative Examples 4 and 5 has been reduced due to the adjustment of the sputtering power. In order to achieve the best technical effect, the sputtering parameters are also one of the key factors affecting the performance. However, overall, it is still much higher than the conventional Al2O3 wafer in Comparative Example 2.

[0070] Furthermore, samples of Example 3 and each comparative example were selected for X-ray diffraction test, and the results are shown in Figure 2 .

[0071] Depend on Figure 2 It can be seen that:

[0072] (a) is the X-ray diffraction pattern of the Y2O3-BZO stacked composite coating prepared in Example 3. Compared with the standard card, it can be seen that both Y2O3 and BZO in the prepared Y2O3-BZO stacked composite coating present a cubic phase.

[0073] (b) is the X-ray diffraction pattern of the Y2O3 single coating prepared in Comparative Example 1. Compared with the standard card, it can be seen that the prepared Y2O3 single coating presents a cubic phase.

[0074] (c) is the X-ray diffraction pattern of the commercial Al2O3 wafer in Comparative Example 2. Compared with the standard card, it can be seen that the commercial Al2O3 wafer presents a rhombohedral phase.

[0075] (d) is the X-ray diffraction pattern of the composite coating prepared by simultaneous sputtering of Y2O3-BZO dual targets in Comparative Example 3, which shows an amorphous structure. This may be because during the dual-target co-sputtering, Y2O3 and BZO atoms react in the cavity to form some new products that are deposited on the substrate.

[0076] (e) is the X-ray diffraction pattern of the Y2O3-BZO stacked composite coating prepared in Comparative Example 4. In the figure, there is only an obvious diffraction peak near 29.3°, indicating that only Y2O3 exists in the coating, and the sputtering power of BZO is too high, which results in BZO not being successfully deposited on the substrate and affecting the overall crystallinity of the coating.

[0077] (f) is the X-ray diffraction spectrum of the Y2O3-BZO stacked composite coating prepared in Comparative Example 5. In the figure, only the relatively obvious Y2O3 diffraction peak can be observed, and the diffraction peak of BZO is not observed. This may be due to insufficient BZO sputtering power, resulting in the plasma not successfully blasting BZO atoms out of the target. It can be seen that the Y2O3-BZO stacked composite coating cannot be formed when the power of the BZO target is too high or too low.

[0078] From the above tests, it can be seen that the composite coating formed by alternately sputtering Y2O3 and BZO targets in this application has good etching resistance, and the etching rate is between 0.67~1.38mm / min, which is significantly higher than conventional etching-resistant coatings. It can play a good protective role for the etcher, extend its life, and reduce the pollution to the wafer.

[0079] The specific raw materials not described in the present invention are all existing materials and can be directly purchased from the market.

[0080] The above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a Y2O3-BZO composite coating suitable for etching machine parts, characterized in that: The following steps are involved: S1. Take the substrate for cleaning, drying, and secondary cleaning with UV light cleaning machine; S2, placing the substrate in step S1 in a magnetron sputtering coating machine, evacuating and heating the substrate, introducing argon gas after reaching the background vacuum, and pre-sputtering the Y2O3 and BZO targets; S3. After the pre-sputtering is completed, the baffle is opened, the chamber pressure is adjusted, and the formal sputtering begins. The formal sputtering adopts an alternating sputtering form to sputter the Y2O3 and BZO targets respectively to form a stacked composite coating. After the sputtering is completed, the substrate is taken out; S4, vacuum annealing the substrate in step S3, and naturally cooling it to obtain a Y2O3-BZO stacked composite coating; In step S2, during pre-sputtering, the sputtering power of the Y2O3 target is 160-200W, and the sputtering power of the BZO target is 40-80W; the pre-sputtering time is 5-15min; In step S3, the chamber pressure during the formal sputtering is 0.2-0.6 Pa, the formal sputtering power is the same as that of the pre-sputtering, and the total formal sputtering time is 200-300 min; The number of stacked composite coating layers is 4 to 24, and the thickness is 400 to 600 nm.

2. The preparation method according to claim 1, characterized in that: In step S1, the substrate is ultrasonically cleaned with acetone, alcohol and deionized water for 10 to 20 minutes in sequence, and then blown dry with N2.

3. The preparation method according to claim 2, characterized in that: The ultrasonic power during the cleaning is 160W-200W, the wavelength of the ultraviolet light emitted by the UV light cleaning machine is 185nm, and the cleaning time is 10-30min.

4. The preparation method according to claim 1, characterized in that: The background vacuum in step S2 is 1×10 -3 Pa, the heating temperature is 250~350℃, and the argon flow rate is 40~80sccm.

5. The preparation method according to claim 1, characterized in that: The vacuum annealing conditions in step S4 are: a heating rate of 9-11°C / min, a temperature of 800-1000°C, a holding time of 1-3h, and a vacuum degree of 100-300Pa.

6. The preparation method according to claim 1, characterized in that: The Y2O3 target material has a diameter of 76.2 mm and a thickness of 3 mm, and is bound to a 2 mm copper backing plate; the BZO target material has a size of 60 mm and a thickness of 3 mm, and is bound to a 2 mm copper backing plate.

7. Use of the Y2O3-BZO composite coating prepared by the method according to any one of claims 1 to 6 in etching equipment.

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