Preparation method of copper-based yttrium oxide coating with self-repairing performance

Abstract

The invention discloses a preparation method of a copper-based yttrium oxide coating with self-repairing performance. The preparation method comprises the following steps: sputtering and depositing on the surface of an oxygen-free copper substrate by adopting a pulse direct-current magnetron sputtering mode to form the yttrium oxide coating; the oxygen-free copper base body containing the yttrium oxide coating is conveyed into a cooling chamber for standing and cooling to form a coating base body; and the coating base body is fed into a tubular furnace, argon and hydrogen mixed protective gas is introduced into the tubular furnace, furnace cooling is conducted after high-temperature annealing is conducted, and the copper-based yttrium oxide coating with the self-repairing performance is formed. After the copper-based yttrium oxide coating with the self-repairing performance cracks, oxygen-free copper of the substrate is combined with oxygen atoms in the environment to generate copper oxide which fills cracks, an embedded coating structure is formed, self-repairing of the coating is achieved, further cracking of the yttrium oxide coating is prevented, and the service life of the coating is prolonged. The copper oxide protective layer at the crack can effectively prevent oxygen from continuously permeating into the lower layer of the coating and the substrate, so that further oxidation and damage of the coating are slowed down, and the service life of the coating is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of material surface treatment, and in particular to a method for preparing a copper-based yttrium oxide coating with self-repairing performance. Background Art

[0002] At present, in the etching process of the semiconductor industry, since some parts in the etching process chamber will be loaded with ultra-high power in a short period of time, resulting in a high temperature of the parts, corresponding copper components are usually used to exchange heat and cool the parts with high temperatures. In this process, the copper components in the etching chamber will also be etched by plasma.

[0003] Under the high temperature and plasma environment in the etching chamber, the copper substrate is easily oxidized and etched, which will seriously affect its service life and performance. It is usually an effective protection technology to prepare a layer of yttrium oxide coating with high heat shock resistance and etching resistance on the surface of copper components by surface coating. However, due to the large difference in thermal expansion coefficient between copper and yttrium oxide (the thermal expansion coefficient of copper is 17.2×10 -6 / K, the thermal expansion coefficient of yttrium oxide is about 7.8×10 -6 / K), which causes the yttrium oxide coating to crack and peel off easily at high temperatures, thereby reducing its durability. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a method for preparing a copper-based yttrium oxide coating with self-healing properties, by spontaneously generating copper oxide under high temperature conditions to fill the gaps in the coating cracks, thereby achieving self-repair of the coating, enhancing the high temperature resistance of the coating, improving the durability and thermal shock resistance of the coating, and thereby extending the service life of the coating.

[0005] A method for preparing a copper-based yttrium oxide coating with self-repairing properties comprises the following steps: Step S11, sending the oxygen-free copper substrate after bombardment and cleaning by a gas ion source into a coating process chamber, and sputtering and depositing an yttrium oxide coating on the surface of the oxygen-free copper substrate by a pulsed DC magnetron sputtering method; Step S12, transferring the oxygen-free copper substrate containing the yttrium oxide coating into a cooling chamber, and cooling it to a preset temperature to form a coating substrate; Step S13, sending the coating substrate into a tubular furnace, and introducing an argon-hydrogen mixed protective gas into the tubular furnace, performing high-temperature annealing and then cooling with the furnace to form a copper-based yttrium oxide coating with self-repairing properties.

[0006] Preferably, in step S11, the sputtering voltage of the magnetron sputtering is in the range of 300-500 V, and the thickness of the yttrium oxide coating is in the range of 1-10 μm.

[0007] Preferably, in step S12, the preset temperature range is 25-75°C.

[0008] Preferably, in step S13, the temperature range of high temperature annealing is 100-500° C., and the flow rate range of the argon-hydrogen mixed gas is 0-10 L / s.

[0009] Preferably, in step S11, the oxygen-free copper substrate is fixed on a substrate frame, and the substrate frame is provided with a pulse bias power supply for applying a negative bias voltage to the oxygen-free copper substrate, and a heating device for heating the oxygen-free copper substrate.

[0010] Preferably, the voltage range of the pulse bias power supply is 50-200V, and the heating temperature range of the heating device is 0-300°C.

[0011] Preferably, the two sputtering cathodes in the coating process chamber are both rectangular cathode structures, and the two sputtering cathodes are symmetrically mounted on the translation track and are at the same height from the surface to be coated.

[0012] Preferably, the distance between each sputtering cathode and the surface to be coated is 8-15 cm.

[0013] Preferably, before step S11, the preparation method further comprises: The oxygen-free copper substrate is transferred to the positioning stand by a soft-contact electric forklift, and the oxygen-free copper substrate is automatically sent to the cleaning equipment for ultrasonic cleaning and drying by a manipulator; The dried oxygen-free copper substrate is automatically transferred to the vacuum chamber by a robot and bombarded and cleaned by a gas ion source.

[0014] Preferably, the gas ion source is a linear anode ion source, the working gas is argon, the adjustable voltage range is 800-1200 V, and the bombardment time range is 10-30 min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: First, the present invention significantly enhances the etching resistance of the substrate by depositing an yttrium oxide coating on the surface of the copper substrate, and is suitable for long-term use in medium and high temperature corrosive environments; Second, after the self-repairing copper-based yttrium oxide coating of the present invention cracks, the oxygen-free copper of the substrate combines with oxygen atoms in the environment to generate copper oxide to fill the cracks, forming a "mosaic" coating structure, thereby achieving self-repair of the coating and preventing further cracking of the yttrium oxide coating. The copper oxide protective layer at the crack can effectively prevent oxygen from continuing to penetrate into the lower layer of the coating and the substrate, thereby slowing down further oxidation and damage of the coating. Third, the coating prepared by the present invention has good high-temperature crack resistance, can maintain a long service life in medium and high temperature environments, and is suitable for semiconductor manufacturing equipment and other high-temperature operating conditions.

[0016] Fourthly, the present invention adopts magnetron sputtering process to deposit yttrium oxide coating, which has the advantages of stable process, strong controllability, and suitability for large-scale production, thereby ensuring the uniformity and consistency of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of a method for preparing a copper-based yttrium oxide coating having self-repairing properties; Figure 2 Schematic diagram of the self-repairing process of the copper-based yttrium oxide coating with self-repairing performance in the present invention; Figure 3 It is a schematic diagram of a production line for preparing a copper-based yttrium oxide coating with self-repairing properties in the present invention; Figure 4 It is a schematic diagram of the installation of the sputtering cathode in the coating process chamber of the present invention; Figure 5 It is a schematic diagram of high temperature annealing of the yttrium oxide coating in a tube furnace in the present invention; Figure 6 A macroscopic surface schematic diagram of a thermal shock test of yttrium oxide coatings grown on different substrates in the present invention; Figure 7 SEM surface morphology images and EDS element analysis images of the yttrium oxide coatings grown on different substrates after thermal shock tests (0 times, 20 times, and 50 times) in the present invention.

[0018] The following specific implementation manner will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0019] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0020] See also Figure 1 and Figure 2 , a method for preparing a copper-based yttrium oxide coating with self-repairing properties provided in one embodiment of the present invention comprises the following steps: Step S11, sending the oxygen-free copper substrate after bombardment and cleaning by a gas ion source into a coating process chamber, and sputtering and depositing an yttrium oxide coating on the surface of the oxygen-free copper substrate by a pulsed DC magnetron sputtering method; Specifically, in step S11, the sputtering voltage of the magnetron sputtering is in the range of 300-500 V, and the thickness of the yttrium oxide coating is in the range of 1-10 μm.

[0021] It should be noted that in step S11, the oxygen-free copper substrate is fixed on a substrate frame, and the substrate frame is provided with a pulse bias power supply for applying a negative bias voltage to the oxygen-free copper substrate and a heating device for heating the oxygen-free copper substrate.

[0022] Specifically, the voltage range of the pulse bias power supply is 50-200V, and the heating temperature range of the heating device is 0-300°C. The purpose is to improve the directionality of the sputtered particles of the magnetron sputtering cathode and promote the mutual diffusion between the yttrium oxide coating and the substrate.

[0023] Step S12, transferring the oxygen-free copper substrate containing the yttrium oxide coating into a cooling chamber, and cooling it to a preset temperature to form a coating substrate; Preferably, in step S12, the preset temperature range is 25-75°C, at which the coating deposition crystallization quality is good.

[0024] Step S13, sending the coating substrate into a tube furnace, and introducing an argon-hydrogen mixed protective gas into the tube furnace, performing high-temperature annealing and then cooling with the furnace to form a copper-based yttrium oxide coating with self-repairing properties; Preferably, in step S13, the temperature range of high temperature annealing is 100-500° C., the flow range of the argon-hydrogen mixed gas is 0-10 L / s, and the mass fraction of hydrogen in the argon-hydrogen mixed gas is 1%, so as to suppress the oxidation reaction of the oxygen-free copper substrate.

[0025] It should be noted that in the present invention, in order to verify the self-healing performance of the copper-based yttrium oxide coating with self-healing performance, the copper-based yttrium oxide coating with self-healing performance is sent into a muffle furnace, subjected to cyclic thermal shock, kept warm for a first preset time, and cooled for a second preset time to spontaneously generate copper oxide at the cracks of the yttrium oxide coating.

[0026] Specifically, in the atmospheric environment, the temperature range of the thermal shock test is 400-800°C, the thermal cycle is 20-100 times, the insulation time is 15-50 minutes, the cooling time is 10-20 minutes, and the cooling method is usually air cooling. In this step, it is proved that after the yttrium oxide coating in the present invention is cracked, copper oxide will be generated to re-bond the yttrium oxide coating, that is, the repair of the yttrium oxide coating is completed.

[0027] It should be noted that the two sputtering cathodes in the coating process chamber are both rectangular cathode structures, and the two sputtering cathodes are symmetrically mounted on the translation track and at the same height from the surface to be coated. In the present invention, the magnetron sputtering cathode is set as a rectangular cathode and mounted on the translation track. When sputtering a large-area substrate, the cathode will reciprocate within a certain range to ensure the uniformity of the film layer, avoiding the sputtering gradient existing in the fixed cathode that makes the film layer uneven in thickness.

[0028] Specifically, the distance between each sputtering cathode and the surface to be coated is 8 to 15 cm.

[0029] Furthermore, before step S11, the preparation method further includes: The oxygen-free copper substrate is transferred to the positioning stand by a soft-contact electric forklift, and the oxygen-free copper substrate is automatically sent to the cleaning equipment for ultrasonic cleaning and drying by a manipulator; The dried oxygen-free copper substrate is automatically transferred to the vacuum chamber by a robot and bombarded and cleaned by a gas ion source.

[0030] Specifically, the gas ion source used in this application is a linear anode ion source, the working gas is argon, the voltage is adjustable in the range of 800-1200V, and the bombardment time range is 10-30min. The purpose is to remove the water molecule film and organic matter remaining on the surface of the substrate to be coated after pretreatment, and to activate the substrate and improve the bonding strength of the film substrate through particle bombardment.

[0031] It should be noted that in this application, when the vacuum degree of the cavity is 8×10 -4 ~1×10 -3 The coating process can be started within the Pa range. After the oxygen-free copper substrates with yttrium oxide coating deposited on the first group enter the cooling chamber, the next group of sample substrates stored in the ion source gas chamber will then enter the coating process chamber for yttrium oxide coating deposition. Therefore, the sputtering cathode does not need to stop working, which improves the sputtering efficiency.

[0032] First, preprocessing In the Class 1000 dust-free workshop, a soft-contact electric forklift is used to transfer the oxygen-free copper substrate to the positioning stand. After the substrate is adjusted to a suitable position, a forklift is used to transfer the substrate to the cleaning equipment. The scanner is used to extract the product's external dimensions. The automated cleaning and transmission section adaptively adjusts the positions of the manipulator, lifting fixture, and transmission wheel according to the product's dimensions. The forklift lifts the substrate to the front section of the cleaning machine where the manipulator grabs it. The manipulator automatically transfers the substrate to the cleaning equipment for cleaning, which includes: ultrasonic liquid cleaning - 1 ultrasonic rinse - 2 ultrasonic rinses - scanning spray - clean air to remove water - vacuum dehydration - cleanliness inspection; In order to prevent the oxygen-free copper substrate from being attached by tiny particles after cleaning, this stage enters the fully automatic transfer process, including: tray splicing - tray transmission - robot grabbing - substrate rack receiving substrate - substrate rack transmission to the cleaning area in the vacuum chamber.

[0033] Second, yttrium oxide coating deposition Multiple groups of substrates enter the storage chamber - evacuate - introduce working gas argon - the first group of substrates enter the ion source chamber - gas plasma surface cleaning - the first group of substrates enter the coating process chamber, and the second group of substrates enter the ion source chamber for gas plasma cleaning - adjust the angle and height of the sputtering cathode to deposit yttrium oxide coating - the first group of substrates undergo pulsed DC magnetron sputtering cathode deposition of yttrium oxide coating - after the preset time is reached, transport them to the storage chamber for cooling, and then the second group of substrates enter the coating process chamber for yttrium oxide coating deposition, and at the same time the third group of substrates enter the ion source chamber - repeat the above steps until all substrates have completed yttrium oxide coating deposition.

[0034] Third, high temperature annealing treatment of yttrium oxide coating Multiple groups of deposited yttrium oxide coating samples are placed in a crucible of a high-temperature tube furnace, ensuring that the samples are stable and do not touch other objects - a suitable atmosphere is selected (the method of the present invention uses an argon-hydrogen mixture) to fill the tube furnace - the temperature is slowly increased to a predetermined annealing temperature - the temperature is kept at the target temperature - the temperature is slowly decreased to room temperature - the samples are taken out at room temperature to obtain a copper-based yttrium oxide coating with self-healing properties.

[0035] Fourth, finished product testing The finished products are subjected to rapid temperature rise and fall cycle tests to check the surface integrity of the yttrium oxide coating of the tested samples, whether there are cracks or wrinkles, etc., to determine whether they meet the standards. After passing the inspection, they are transferred to a nitrogen-protected storage box.

[0036] See also Figures 3 to 5 In another embodiment of the present invention, a method for preparing a copper-based yttrium oxide coating with self-repairing properties is provided, and the experimental contents are as follows: The oxygen-free copper substrate with a size of 20×20×2mm was pretreated and sent to the gas ion source chamber for ion bombardment cleaning after treatment. It was transferred to the coating chamber and a pulsed DC magnetron sputtering rectangular cathode was used to grow the yttrium oxide coating. The rectangular cathode yttrium target voltage was set to 280V, and the thickness of the yttrium oxide coating formed on the surface was about 2μm. After the deposition was completed, the substrate temperature was cooled to 30°C, and the yttrium oxide coating was transferred to a tube furnace for high-temperature annealing at 400°C under the conditions of argon-hydrogen mixed gas. The finished product was then subjected to a heat shock resistance test.

[0037] See also Figure 4 The substrate holder where the oxygen-free copper substrate is located can be loaded with a negative pulse bias voltage and is equipped with a heating device. Combined with the pulse DC power supply used in the rectangular cathode sputtering yttrium oxide coating, it can improve the directionality of the magnetron sputtering cathode sputtering particles and promote the mutual diffusion between the oxygen-free copper substrate and the yttrium oxide coating, thereby improving the deposition quality of the yttrium oxide coating and the film-base bonding strength.

[0038] See also Figure 5A tubular furnace is used for high temperature annealing, and the gas introduced is an argon-hydrogen mixture. The introduction of protective gas can prevent the copper substrate from oxidizing at high temperature and stabilize the high temperature annealing process.

[0039] See also Figure 6 The figure shows the surface macroscopic morphology of yttrium oxide coatings grown on different substrates (single crystal silicon substrate, oxygen-free copper substrate) under 600°C thermal shock conditions (0 times, 20 times, 50 times). It can be concluded from the figure that the yttrium oxide coating grown on the oxygen-free copper substrate has good high temperature resistance.

[0040] See also Figure 7 The figure shows the SEM surface morphology and EDS element distribution spectrum of yttrium oxide coatings grown on different substrates (single crystal silicon substrate, oxygen-free copper substrate) under 600°C thermal shock conditions (10 times, 20 times, 50 times). It can be seen from the figure that the yttrium oxide coating grown on single crystal silicon produced delamination after 10 thermal shocks, and the substrate was exposed; while the yttrium oxide coating grown on the oxygen-free copper substrate produced self-repairing phenomenon, and the substrate was not exposed.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a copper-based yttrium oxide coating with self-repairing properties, characterized in that: The following steps are involved: Step S11, sending the oxygen-free copper substrate that has been bombarded and cleaned by a gas ion source into a coating process chamber, and sputtering and depositing an yttrium oxide coating on the surface of the oxygen-free copper substrate by a pulsed DC magnetron sputtering method; Step S12, transferring the oxygen-free copper substrate containing the yttrium oxide coating into a cooling chamber, and cooling it to a preset temperature to form a coating substrate; Step S13, sending the coating substrate into a tubular furnace, and introducing an argon-hydrogen mixed protective gas into the tubular furnace, performing high-temperature annealing and then cooling with the furnace to form a copper-based yttrium oxide coating with self-repairing properties.

2. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: In step S11 , the sputtering voltage of the magnetron sputtering is in the range of 300-500 V, and the thickness of the yttrium oxide coating is in the range of 1-10 μm.

3. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: In step S12, the preset temperature range is 25-75°C.

4. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: In step S13, the temperature range of high temperature annealing is 100-500°C, and the flow range of the argon-hydrogen mixed gas is 0-10 L / s.

5. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: In step S11, the oxygen-free copper substrate is fixed on a substrate frame, and the substrate frame is provided with a pulse bias power supply for applying a negative bias voltage to the oxygen-free copper substrate and a heating device for heating the oxygen-free copper substrate.

6. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 5, characterized in that: The voltage range of the pulse bias power supply is 50-200V, and the heating temperature range of the heating device is 0-300°C.

7. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: The two sputtering cathodes in the coating process chamber are both rectangular cathode structures. The two sputtering cathodes are symmetrically installed on the translation track and are at the same height from the surface to be coated.

8. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 7, characterized in that: The distance between each sputtering cathode and the surface to be coated is 8~15cm.

9. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 1, characterized in that: Before step S11, the preparation method further includes: The oxygen-free copper substrate is transferred to the positioning stand by a soft-contact electric forklift, and the oxygen-free copper substrate is automatically sent to the cleaning equipment for ultrasonic cleaning and drying by a manipulator; The dried oxygen-free copper substrate is automatically transferred to the vacuum chamber by a robot and bombarded and cleaned by a gas ion source.

10. The method for preparing a copper-based yttrium oxide coating with self-repairing properties according to claim 9, characterized in that: The gas ion source is a linear anode ion source, the working gas is argon, the adjustable voltage range is 800~1200V, and the bombardment time range is 10~30min.

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