Method for reducing particles in atomic deposition chamber

Abstract

The invention relates to an atomic deposition technology, in particular to a method for reducing particles in an atomic deposition chamber, which is based on an existing atomic deposition chamber structure and is characterized in that a chamber is made of 6061 aluminum alloy, an aluminum oxide film layer is generated on the inner surface of the chamber by performing sand blasting treatment, ultrasonic cleaning and surface oxidation treatment on the chamber, and the particles in the chamber are reduced. The obtained cavity is not easy to fall off, the service life of the cavity is greatly prolonged, and the material cost and the labor cost are reduced; the quality of the film layer prepared by the chamber obtained by the method is greatly improved, and particles in the deposited film layer are greatly reduced.

Description

Technical Field

[0001] The invention relates to atomic deposition technology, in particular to a method for reducing particles in an atomic deposition chamber. Background Art

[0002] Atomic layer deposition (ALD) technology is a special chemical vapor deposition technology. It is a method of forming a thin film by alternately passing gaseous precursor pulses into the reaction chamber and undergoing chemical adsorption reaction on the surface of the deposition substrate. It has the characteristics of excellent three-dimensional conformality, large-area uniformity and precise sub-monolayer film thickness control. In particular, atomically deposited films have good compatibility with semiconductor processes and unique self-limited growth, which makes them widely favored in the microelectronics industry and nanotechnology. In recent years, ALD technology has been widely used in microelectronics, optoelectronics, optics, nanotechnology, micromechanical systems, energy, catalysis, biomedicine, corrosion resistance and sealing coatings. However, as the thickness of the film increases, the film layer in the chamber is prone to fall off, resulting in more particles in the prepared film layer and poor film quality, and a short chamber service life.

[0003] Taking the growth of aluminum oxide film by the reaction of trimethylaluminum and ozone as an example, since the traditional chamber is made of stainless steel, while the aluminum oxide film is growing, the aluminum oxide film is also deposited on the inner wall of the chamber. The aluminum oxide film and the chamber rely on physical adsorption, and the adhesion is very small. As the aluminum oxide film continues to grow, the stress in the film gradually increases. When the stress increases to a certain extent, it will cause the aluminum oxide film to partially fall off, causing particles to contaminate the entire reaction chamber and fall into the growing aluminum oxide film, resulting in reduced film quality. With the development of the semiconductor industry, especially the continuous reduction of the key size of integrated circuit chips, the requirements for film particle defects in the manufacturing process of semiconductor integrated circuits are getting higher and higher. Atomic deposition mainly deposits interlayer dielectric films in semiconductor integrated circuits and passivation layers of organic solar energy, displays and other devices. If the atomically deposited film contains a large number of particle defects, it will cause circuit short circuit or open circuit, affecting the passivation effect and yield of the device, and even film explosion, etc., seriously affecting the yield of the wafer and device performance. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for reducing particles in an atomic deposition chamber.

[0005] The method for reducing particles in an atomic deposition chamber of the present invention is based on the existing atomic deposition chamber structure. The chamber is made of 6061 aluminum alloy. The specific operation steps are as follows: 1) Sandblasting the chamber; Sandblasting is a pretreatment process that roughens the surface of the aluminum alloy and has a significant impact on the subsequent oxidation process. During the sandblasting process, the high-speed abrasive jets physically impact the surface of the aluminum alloy, remove the oxide film, oil stains and other impurities on the surface, form a microscopic uneven surface structure, increase the roughness of the aluminum alloy surface, and facilitate the deposition and formation of oxides during the surface oxidation process.

[0006] 2) Ultrasonic cleaning is performed on the chamber after sandblasting to remove stains and residual sandblasting particles on the inner surface of the chamber.

[0007] 3) The surface of the chamber is oxidized to form an aluminum oxide film on the inner surface of the chamber. The aluminum oxide film has the advantage of being similarly miscible with the aluminum oxide deposited film grown later, and is easy to form chemical adsorption, making the process chamber cleaner and reducing particle generation.

[0008] Specifically, in step 1), diamond sand is used for sandblasting, and the sandblasting specification is 150 mesh, so that the surface of the chamber has a certain degree of roughness, so that the film layer deposited later is not easy to fall off. Specifically, the specific method of oxidation treatment in step 3) is: placing the chamber in an electrolyte, wherein the electrolyte is composed of 7g / L K 2 SiO 3 , 5g / L Na 2 O 2、 0.6 g / L NaF and 2.6 g / L CH 3 The electrolyte is mixed with COONa solution, the pH value of the electrolyte is 12, and the temperature is set to 50°C for electrolysis. The anode voltage is first rapidly increased to 300 V and maintained for 10 seconds, and then the anode voltage is increased to 450 V and maintained for 2 minutes. A 25-micron thick aluminum oxide film layer is formed on the surface of the chamber.

[0009] Compared with the prior art, the present invention has the following technical effects and advantages: Compared with stainless steel, aluminum alloy has lower hardness and is easier to cast the required chamber structure; The chamber obtained by the method is not easy to fall off, the service life of the chamber is greatly increased, and the material cost and labor cost are reduced; The quality of the film layer prepared in the chamber obtained by this method is greatly improved, and the particles in the deposited film layer are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 These are comparison images of scanning electron microscope (SEM) of 6061 aluminum alloy chambers, where: (a) is the SEM image of the chamber surface before sandblasting, which is relatively smooth; (b) is the SEM image of the chamber surface after sandblasting, which is relatively rough.

[0011] Figure 2 The SEM and X-ray energy dispersive spectrometer (EDS) images of the chamber surface after oxidation treatment show that an oxide layer with a thickness of about 34 μm is formed on the surface after oxidation. Figure 2 As shown in (a), the main elements of the surface oxide layer analyzed by X-ray energy dispersive spectrometer (EDS) are aluminum and oxygen, indicating that an aluminum oxide film layer has formed on the surface of the chamber. Figure 2 (b).

[0012] Figure 3 The figures are actual comparison pictures of different chamber accessories after a certain number of processes, wherein the accessories are part of the chamber, wherein: 3(a) is an actual picture of a 316 stainless steel chamber accessory without any treatment and after the process number (150 times) has been deposited with aluminum oxide, 3(b) is an actual picture of an accessory processed by the present invention and after the process number (150 times) has been deposited with aluminum oxide, it can be seen that the aluminum oxide film layer deposited in the treated chamber has better adhesion than the aluminum oxide film layer deposited in the 316 stainless steel chamber and is not easy to fall off.

[0013] Figure 4 .Comparison of the particles of the deposited aluminum oxide film prepared in different chambers, where: (a) is the particle size of the deposited aluminum oxide film obtained in the 316 stainless steel chamber without any treatment; (b) is the particle size of the deposited aluminum oxide film obtained in the chamber treated by the present method. It is obvious that the aluminum oxide film prepared by the present invention has much fewer particles. DETAILED DESCRIPTION

[0014] Embodiment 1: A method for reducing particles in an atomic deposition chamber, using 6061 aluminum alloy material to cast a required chamber using a casting process, the shape and structure of the chamber can be specifically designed according to the type of accessories prepared, and the specific implementation steps include: 1) Sandblasting: The sandblasting process uses compressed air as a power source to form a high-speed jet beam to spray the material onto the surface of the chamber. The material is quartz sand, and the sandblasting specification is 150 mesh. Figure 1 shown.

[0015] 2) Perform ultrasonic cleaning after sandblasting to remove surface stains and residual sandblasting particles.

[0016] 3) Place the chamber in an electrolyte consisting of 7 g / L K 2 SiO 3 , 5g / L Na 2 O 2、 0.6 g / L NaF and 2.6 g / L CH 3COONa solution, the pH of the electrolyte was 12, the temperature was set at 50 °C for electrolysis, the anode voltage was quickly increased to 300 V and maintained for 10 s, then the anode voltage was increased to 450 V and maintained for 2 minutes, and a layer of aluminum oxide film with a thickness of 34 μm was formed on the surface of the chamber. Figure 2 shown.

[0017] Comparative Example: Use 316 stainless steel material to cast the required chamber by casting process, place a single-polished silicon wafer in the chamber and deposit a film layer. After the film is formed, use a particle meter to test the particles. The number of particles in the film layer is significantly more than that of the film layer prepared by 6061 aluminum alloy. Figure 4 shown.

Claims

1. A method for reducing particles in an atomic deposition chamber, based on an existing atomic deposition chamber structure, characterized in that The chamber is made of 6061 aluminum alloy, and the specific operation steps are as follows: Sandblast the chamber; Ultrasonic cleaning of the chamber after sandblasting; The chamber is subjected to surface oxidation treatment to form an aluminum oxide film layer on the inner surface of the chamber.

2. A method for reducing particles in an atomic deposition chamber as claimed in claim 1, characterized in that In step 1), the sandblasting is performed using corundum with a sandblasting specification of 150 mesh.

3. A method for reducing particles in an atomic deposition chamber as claimed in claim 1, characterized in that The specific method of oxidation treatment in step 3) is: placing the chamber in an electrolyte, wherein the electrolyte is composed of 7g / L K2SiO3, 5g / L Na2O 2、 0.6 g / L NaF and 2.6 g / L CH3COONa solution were mixed, the pH of the electrolyte was 12, and the temperature was set to 50°C for electrolysis. The anode voltage was first rapidly increased to 300 V and maintained for 10 seconds, then the anode voltage was increased to 450 V and maintained for 2 minutes. A 34-micron thick aluminum oxide film layer was formed on the chamber surface.

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