Reaction chamber for enhancing chemical vapor deposition and plasma homogenization method

Abstract

The invention relates to the technical field of vapor deposition, and discloses a reaction cavity for enhancing chemical vapor deposition, which comprises a cavity main body, two ends of the cavity main body are respectively provided with a gas inlet and an extraction opening, the surface of the inner wall of the cavity main body is provided with an insulation shielding layer, and the inner wall of the cavity main body is provided with a magnetic field enhancing assembly in a surrounding manner. An objective table is arranged close to the bottom of the inner wall of the cavity main body, a sub-electrode is arranged close to the upper end of the inner wall of the cavity main body, the cavity main body comprises a cylindrical shape and a rectangular shape, a heating device is integrated in the objective table, and a magnetic field enhancing assembly restrains plasma through a radial magnetic field to reduce collision loss with the cavity wall. The plasma density of the marginal area is increased by 20-30%; the distributed radio frequency electrodes can realize partition power regulation and control, and the thickness uniformity error of the thin film on the surface of the silicon wafer is controlled within + / -2% in combination with dynamic compensation of real-time monitoring data.

Description

Technical Field

[0001] This invention relates to the field of vapor deposition technology, specifically to a reaction chamber and plasma homogenization method for enhancing chemical vapor deposition. Background Technology

[0002] In the production of photovoltaic crystalline silicon cells, silicon nitride thin films serve as both antireflection and passivation layers, and their deposition quality directly affects the cell's conversion efficiency. Plasma-enhanced chemical vapor deposition (PECVD) is the mainstream technology. Its principle is to generate plasma by exciting reactive gases (such as SiH4 and NH3) with a radio frequency electric field, causing the gas molecules to dissociate and undergo a chemical reaction on the silicon wafer surface to form a thin film.

[0003] In existing technologies, the plasma distribution in the PECVD reaction chamber is susceptible to edge effects: plasma near the chamber wall loses energy due to collisions with the wall, resulting in an uneven distribution with "high density at the center and low density at the edges." This leads to a 5%-10% deviation in film thickness on the silicon wafer surface and a reduction in deposition efficiency of over 15%. To address this issue, existing solutions often involve optimizing the gas guide plate or adjusting the power of a single radio frequency unit, but these methods fail to fundamentally improve the problem of insufficient plasma confinement, especially in the deposition of large-area silicon wafers (such as 182mm and 210mm wafers), where uniformity control is even more challenging.

[0004] To this end, we propose a reaction chamber and plasma homogenization method for enhancing chemical vapor deposition. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a reaction chamber and plasma homogenization method for enhancing chemical vapor deposition, thereby solving the aforementioned problems.

[0006] The present invention provides the following technical solution: a reaction chamber for enhancing chemical vapor deposition, comprising a chamber body, with a gas inlet and a gas extraction port respectively provided at both ends of the chamber body, an insulating shielding layer provided on the inner wall surface of the chamber body, a magnetic field enhancement component surrounding the inner wall of the chamber body, a stage provided near the bottom of the inner wall of the chamber body, and a sub-electrode provided near the upper end of the inner wall of the chamber body. The chamber body includes cylindrical and rectangular shapes, and a heating device is integrated inside the stage.

[0007] Preferably, the number of magnetic field enhancement components is not less than two, and they are axially spaced in the cavity to form a radially constrained magnetic field. The magnetic field enhancement components include permanent magnets and electromagnetic coils.

[0008] Preferably, the number of sub-electrodes is not less than four, and they are arranged in an array. Each sub-electrode is connected to the radio frequency power supply through a matching network, and its output power can be adjusted independently.

[0009] Preferably, the material of the insulating shielding layer includes aluminum oxide and aluminum chloride, and the thickness of the insulating shielding layer is 0.5-2 mm.

[0010] Preferably, the magnetic poles of adjacent magnetic field enhancement components are arranged in opposite directions, and the magnetic field strength can be adjusted within the range of 50-500 Gauss.

[0011] Preferably, the sub-electrodes are arranged in concentric rings or in a matrix, and the power adjustment accuracy of a single sub-electrode is ±0.1W, with a radio frequency of 13.56MHz or 27.12MHz.

[0012] A plasma-based homogenization method for enhancing the reaction chamber of chemical vapor deposition includes the following steps: The first step is to place the silicon wafer on the stage, close the cavity, and evacuate it to 1-10 Pa. The second step is to introduce a mixture of SiH4 and NH3 gas through the gas inlet at a flow ratio of 1:5 to 1:10, with a total flow rate of 2000-5000 sccm. The third step is to activate the magnetic field enhancement component and apply an initial magnetic field strength of 100-200 Gauss to constrain the plasma to diffuse toward the edge. The fourth step is to start the sub-electrodes, with the total power set to 500-1500W. The initial power of each sub-electrode is distributed according to the ratio of 60%-70% in the central area and 80%-90% in the edge area. The fifth step involves monitoring the plasma density in different regions of the silicon wafer surface in real time during the deposition process using optical emission spectroscopy (OES) (monitoring the N2 spectral line at a wavelength of 337 nm or the SiH spectral line at a wavelength of 413 nm). Step 6: Dynamically adjust based on monitoring data: If the plasma density in the edge region is more than 10% lower than that in the center region, increase the power of the corresponding sub-electrode by 5%-10% and increase the magnetic field strength by 50-100 Gauss. Step 7: After deposition is complete, turn off the RF power supply, magnetic field enhancement components and gas passage in sequence, and remove the silicon wafer.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. The magnetic field enhancement component confines the plasma through a radial magnetic field, reducing collision losses with the cavity wall and increasing the plasma density in the edge region by 20%-30%. 2. Distributed RF electrodes enable zoned power regulation, and combined with real-time monitoring data for dynamic compensation, the uniformity error of the thin film thickness on the silicon wafer surface is controlled within ±2%. 3. The insulating shielding layer reduces the adsorption of plasma on the cavity wall, increasing raw material utilization by 15% and deposition efficiency by more than 20%; 4. Suitable for high-speed deposition of large-size silicon wafers (≥182mm), reducing single-batch processing time by 10%-15%. Attached Figure Description

[0014] Figure 1 The left and right views are schematic diagrams of the external structure of the device of the present invention; Figure 2 This is a schematic diagram of the internal structure of the present invention; Figure 3 This is a cross-sectional view of the internal structure of the present invention.

[0015] In the diagram: 1. Main body of the cavity; 2. Gas inlet; 3. Exhaust port; 4. Stage; 5. Magnetic field enhancement component; 6. Sub-electrode; 7. Insulating shielding layer. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0017] The present invention provides the following technical solution: a reaction chamber for enhancing chemical vapor deposition, comprising a chamber body 1, wherein a gas inlet 2 and a gas extraction port 3 are respectively provided at both ends of the chamber body 1, an insulating shielding layer 7 is provided on the inner wall surface of the chamber body 1, a magnetic field enhancement component 5 is arranged around the inner wall of the chamber body 1, a stage 4 is arranged near the bottom of the inner wall of the chamber body 1, and a sub-electrode 6 is arranged near the upper end of the inner wall of the chamber body 1. The chamber body 1 includes cylindrical and rectangular shapes, and a heating device is integrated inside the stage 4.

[0018] The heating device includes electric heating elements, etc., and is powered by an external power source.

[0019] The number of magnetic field enhancement components 5 is not less than two, and they are axially spaced in the cavity to form a radially constrained magnetic field. The magnetic field enhancement components 5 include permanent magnets and electromagnetic coils.

[0020] The number of sub-electrodes 6 is no less than four, and they are arranged in an array. Each sub-electrode is connected to the radio frequency power supply through a matching network, and its output power can be adjusted independently.

[0021] The insulating shielding layer 7 is made of aluminum oxide and aluminum chloride, and the thickness of the insulating shielding layer 7 is 0.5-2 mm.

[0022] The magnetic poles of adjacent magnetic field enhancement components 5 are arranged in opposite directions, and the magnetic field strength can be adjusted within the range of 50-500 Gauss.

[0023] Preferably, the sub-electrodes 6 are arranged in a concentric ring or matrix, and the power adjustment accuracy of a single sub-electrode is ±0.1W, with a radio frequency of 13.56MHz or 27.12MHz.

[0024] A plasma-based homogenization method for enhancing the reaction chamber of chemical vapor deposition includes the following steps: The first step is to place the silicon wafer on stage 4, close the cavity and evacuate it to 1-10 Pa; The second step is to introduce a mixture of SiH4 and NH3 gas through gas inlet 2, with a flow ratio of 1:5 to 1:10 and a total flow rate of 2000-5000 sccm. The third step is to activate the magnetic field enhancement component 5 and apply an initial magnetic field strength of 100-200 Gauss to constrain the plasma to diffuse toward the edge. The fourth step is to start sub-electrode 6, with the total power set to 500-1500W. The initial power of each sub-electrode is distributed according to the ratio of 60%-70% in the central area and 80%-90% in the edge area. The fifth step involves monitoring the plasma density in different regions of the silicon wafer surface in real time during the deposition process using optical emission spectroscopy (OES) (monitoring the N2 spectral line at a wavelength of 337 nm or the SiH spectral line at a wavelength of 413 nm). Step 6: Dynamically adjust based on monitoring data: If the plasma density in the edge region is more than 10% lower than that in the center region, increase the power of the corresponding sub-electrode by 5%-10% and increase the magnetic field strength by 50-100 Gauss. Step 7: After deposition is complete, turn off the RF power supply, magnetic field enhancement components and gas passage in sequence, and remove the silicon wafer.

[0025] Through the above structure and method, the present invention can achieve the following effects: The magnetic field enhancement component confines the plasma through a radial magnetic field, reducing collision losses with the cavity wall and increasing the plasma density in the edge region by 20%-30%; the distributed radio frequency electrodes can achieve zoned power regulation, and combined with real-time monitoring data for dynamic compensation, the uniformity error of the thin film thickness on the silicon wafer surface can be controlled within ±2%; the insulating shielding layer reduces the adsorption of plasma by the cavity wall, increasing the raw material utilization rate by 15% and the deposition efficiency by more than 20%; it is suitable for high-speed deposition of large-size silicon wafers (≥182mm), and the single batch processing time is shortened by 10%-15%.

[0026] It should be noted that the electrical components and equipment mentioned above all use external power sources. The circuits, electronic components, and modules involved in this invention are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The scope of protection of this invention does not involve improvements to the internal structure and methods. Furthermore, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A reaction chamber for enhancing chemical vapor deposition, characterized in that: The cavity includes a main body (1), with a gas inlet (2) and an exhaust port (3) at its two ends respectively. An insulating shielding layer (7) is provided on the inner wall surface of the main body (1). A magnetic field enhancement component (5) is arranged around the inner wall of the main body (1). A stage (4) is provided near the bottom of the inner wall of the main body (1). A sub-electrode (6) is provided near the upper end of the inner wall of the main body (1). The main body (1) includes cylindrical and rectangular shapes. A heating device is integrated inside the stage (4).

2. The reaction chamber for enhancing chemical vapor deposition according to claim 1, characterized in that: The number of magnetic field enhancement components (5) is not less than two, and they are distributed axially in the cavity to form a radially constrained magnetic field. The magnetic field enhancement components (5) include permanent magnets and electromagnetic coils.

3. The reaction chamber for enhancing chemical vapor deposition according to claim 1, characterized in that: The number of sub-electrodes (6) is no less than four, and they are arranged in an array. Each sub-electrode is connected to the radio frequency power supply through a matching network and its output power can be adjusted independently.

4. The reaction chamber for enhancing chemical vapor deposition according to claim 1, characterized in that: The insulating shielding layer (7) is made of aluminum oxide and aluminum chloride, and the insulating shielding layer (7) has a thickness of 0.5-2 mm.

5. The reaction chamber for enhancing chemical vapor deposition according to claim 2, characterized in that: The magnetic poles of adjacent magnetic field enhancement components (5) are arranged in opposite directions, and the magnetic field strength can be adjusted in the range of 50-500 Gauss.

6. The reaction chamber for enhancing chemical vapor deposition according to claim 1, characterized in that: The sub-electrodes (6) are arranged in concentric rings or in a matrix. The power adjustment accuracy of a single sub-electrode is ±0.1W, and the radio frequency is 13.56MHz or 27.12MHz.

7. A plasma-based homogenization method for enhancing a reaction chamber in chemical vapor deposition, characterized in that: Includes the following steps: First, place the silicon wafer on the stage (4), close the cavity and evacuate to 1-10 Pa; The second step is to introduce a mixture of SiH4 and NH3 gas through the gas inlet (2) with a flow ratio of 1:5-1:10 and a total flow rate of 2000-5000 sccm. The third step is to activate the magnetic field enhancement component (5) and apply an initial magnetic field strength of 100-200 Gauss to constrain the plasma to diffuse toward the edge. The fourth step is to start the sub-electrode (6), with the total power set to 500-1500W. The initial power of each sub-electrode is allocated according to the ratio of 60%-70% in the central area and 80%-90% in the edge area. The fifth step involves monitoring the plasma density in different regions of the silicon wafer surface in real time during the deposition process using optical emission spectroscopy (OES) (monitoring the N2 spectral line at a wavelength of 337 nm or the SiH spectral line at a wavelength of 413 nm). Step 6: Dynamically adjust based on monitoring data: If the plasma density in the edge region is more than 10% lower than that in the center region, increase the power of the corresponding sub-electrode by 5%-10% and increase the magnetic field strength by 50-100 Gauss. Step 7: After deposition is complete, turn off the RF power supply, magnetic field enhancement components and gas passage in sequence, and remove the silicon wafer.

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