DE-102024133196-A1 - Plasma electrode that can be moved within a process chamber of a CVD reactor

DE102024133196A1DE 102024133196 A1DE102024133196 A1DE 102024133196A1DE-102024133196-A1

Abstract

The invention relates to a device for depositing a layer on a substrate (1) in a process chamber (4) arranged in a housing of a CVD reactor (3), with a gas inlet element (5) for introducing gases into the process chamber (4), with a gas outlet surface (8) having a plurality of gas outlet openings (6, 7) through which the gases can flow into the process chamber (4), with at least one plasma electrode (10) that can be supplied with an electrical voltage by a plasma generator (9) and is configured to supply energy to a gaseous starting material in order to generate a plasma, wherein the plasma electrode (10) is arranged to be displaceable in the process chamber (4).

Inventors

Kenneth Boh Khin Teo
Matthew William Mason
Richard John Walker
Ben Richard Conran

Assignees

AIXTRON Ltd.

Dates

Publication Date: 20260513
Application Date: 20241113

Claims (14)

Device for depositing a layer on a substrate (1) in a process chamber (4) arranged in a housing (2) of a CVD reactor (3), with a gas inlet element (5) for introducing gases into the process chamber (4), with a gas outlet surface (8) having a plurality of gas outlet openings (6, 7) through which the gases can flow into the process chamber (4), with at least one plasma electrode (10) that can be supplied with an electrical voltage by a plasma generator (9) and which is configured to supply energy to a gaseous starting material in order to generate a plasma, characterized in that the plasma electrode (10) is arranged to be displaceable in the process chamber (4).
Device according to Claim 1 , characterized in that the plasma electrode (10) is a plate arranged between the gas outlet surface (8) of the gas inlet organ (5) or a process chamber ceiling (30) and a susceptor (11) which limits the process chamber (4) downwards.
Device according to one of the preceding claims, characterized in that a wall (12) surrounding the process chamber (4) and/or a susceptor (11) limiting the process chamber (4) downwards and/or the gas inlet element (5) and/or the process chamber ceiling (30) forms a grounded counter electrode.
Device according to one of the preceding claims, characterized in that the plasma electrode (10) is height-adjustable by means of lifting elements (17).
Device according to one of the preceding claims, characterized in that the plasma electrode (10) has a plurality of gas outlet openings (7).
Device according to one of the preceding claims, characterized in that the plasma electrode (10) can be moved from a contact position in which the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) of the gas inlet element (5) or with the process chamber ceiling (30) or is arranged at a distance (H1) to the gas outlet surface (8) or the process chamber ceiling (30), which is in particular less than 1 mm, into one or more distance positions to the gas outlet surface (8) of the gas inlet element (5) in which the distance (H1) of the plasma electrode (10) to the gas outlet surface (8) is in particular greater than 1 mm.
A method for cleaning surfaces in a process chamber (4) of a device according to one of the preceding claims, comprising the following steps: Positioning the plasma electrode (10) from a contact position in which the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) of the gas inlet element (5) or is arranged at a distance (H1) from the gas outlet surface (8) or the process chamber ceiling (30), which is in particular less than 1 mm, to a first distance position in which the distance (H1) of the plasma electrode (10) to the gas outlet surface (8) or the process chamber ceiling (30) is greater than in the contact position, in particular greater than 1 mm; Introducing a first cleaning gas into the process chamber (4); Plasma activation of the first cleaning gas by applying a voltage to the plasma electrode (10) so that radicals are formed; Removal of residues from the surfaces by reaction with the radicals, in particular from the gas outlet surface (8) of the gas inlet device (5) and/or the process chamber ceiling (30) and/or the plasma electrode (10) and/or the susceptor (11).
Procedure according to Claim 7 , characterized by the following further steps: positioning the plasma electrode (10) in a second spacing position or relocating the susceptor (11) which delimits the process chamber (4) downwards into a position in which the first plasma electrode (10) has a smaller distance (H3) to the susceptor (11) compared to the first spacing position; introducing the first or a second cleaning gas into the process chamber (4); activating the first or second cleaning gas by a plasma generated by the plasma electrode (10) so that radicals are formed; removing residues from the surfaces, in particular from the plasma electrode (10) and the susceptor (11).
Procedure according to Claim 7 , characterized in that the first cleaning gas and/or the second cleaning gas is a halogen gas or a reducing or oxidizing gas or a gas suitable for ion bombardment or mixtures or compounds thereof, which is optionally fed into the process chamber (4) together with a carrier gas.
Procedure according to Claim 8 or 9 , characterized in that in the first and/or second spacing position, the generated radicals leave residues on the surfaces of one or more objects located on the process chamber floor (11). Substrates (1) and/or any layers deposited on the substrates (1) are removed.
Procedure according to one of the Claims 8 , 9 or 10 , characterized in that after cleaning a coating process is carried out in the process chamber (4), wherein the plasma electrode (10) is moved into a position in which a top surface of the plasma electrode (10) is at least partially in contact with the gas outlet surface (8) or the process chamber ceiling (30) or is arranged at a distance (H1) of less than 1 mm from the gas outlet surface (8) or the process chamber ceiling (30), wherein one or more process gases are introduced into the process chamber (4), wherein decomposition products of the process gases are deposited as a layer on the substrates.
Method for depositing a layer on a substrate (1) in a process chamber (4) of a CVD reactor (3) according to one of the Claims 1 until 5 , wherein the process chamber (4) is bounded downwards by a process chamber floor (11) on which one or more substrates (1) are arranged, comprising the following steps: positioning the plasma electrode (10) bounding the process chamber (4) upwards in a spaced position in which the plasma electrode (10) is arranged at an electrically insulating distance to the gas outlet surface (8) or the process chamber ceiling (30); introducing one or more process gases into the process chamber (4), wherein the process gases are decomposed by a plasma generated by the plasma electrode (10), the decomposition products of the process gases growing on the surface of the substrates (1) to form a coating.
Procedure according to one of the Claims 8 until 12 , characterized in that the voltage or power acting on the plasma electrode (10) is increased in such a way that the plasma spreads both above and below the plasma electrode (10).
Device or method characterized by one or more of the characterizing features of one of the preceding claims.

Description

field of technology The invention relates to a device for depositing a layer on a substrate in a process chamber arranged in a housing of a CVD reactor, with a gas inlet device for introducing gases into the process chamber, with a gas outlet surface having a plurality of gas outlet openings through which the gases can flow into the process chamber, with at least one plasma electrode that can be supplied with an electrical voltage by a plasma generator and which is configured to supply energy to a gaseous starting material in order to generate a plasma. State of the art During the deposition of layers onto substrates in a process chamber of a CVD reactor, process gases introduced into the chamber via a gas inlet are decomposed pyrolytically or catalytically. The resulting decomposition products crystallize not only on the substrates but also on other surfaces within the process chamber exposed to the process gases. This undesirable parasitic growth generates impurities that contaminate substrates stored in the process chamber during subsequent processes. This reduces the efficiency and reproducibility of these subsequent processes and impairs the growth behavior of the layer being deposited on the substrates. To remove such parasitic deposits from the surfaces of the process chamber, cleaning processes are typically carried out within the chamber. These processes involve introducing cleaning gases such as Cl₂ , HCl, NH₃ , H₂ , or O₂ . For these gases to form the radicals necessary for surface cleaning, comparatively high cleaning temperatures of several hundred degrees Celsius are required within the process chamber for an extended period. Particularly in a CVD reactor, where the walls or ceiling of the process chamber are directly cooled, a high heat output is required to raise the surface temperature of the process chamber, heated by the susceptor through thermal radiation, to the desired cleaning temperature. This results in high energy consumption for the heating equipment required to heat the susceptor. On the other hand, long cleaning processes in practice lead to considerable downtimes during which the CVD reactor is unproductive, meaning no growth processes can be carried out in the process chamber, thus significantly reducing the overall productivity of the CVD reactor. The EP 2 876 083 B1 The disclosure relates to a device with a gas inlet element through which various gases can be fed into a process chamber. A plasma electrode, which can be subjected to an electrical voltage, is arranged in the gas inlet element and can be used to ignite a plasma in order to associate or dissociate gaseous starting materials. These gaseous starting materials can be precursor organases used in growth processes or cleaning gases used for cleaning a process chamber. The cleaning gases can be converted into cleaning radicals by means of the plasma to remove deposits from surfaces within the process chamber. The plasma electrode can be a plate forming a plurality of openings, arranged within the gas inlet element between two grounded shield electrodes, which are also plates. The US 2002/012976 A1 This describes a CVD reactor with a showerhead gas inlet through which various process gases are fed into a process chamber. To convert the process gases into radicals, a plate-shaped plasma electrode is located within the gas inlet above the gas outlet plate, through which the gases flow into the process chamber. To ignite a plasma within the gas inlet, the plate is energized by a voltage source located outside the reactor housing. The plate is contacted by an RF rod passing through the housing roof. The gas outlet plate is grounded by contact with the housing roof and acts as the counter electrode. The US 2010/0072054 A1 Disclosing a CVD reactor with a showerhead-type gas inlet, through which various gases can be introduced into a process chamber of the CVD reactor. The gas inlet has a gas outlet plate facing the process chamber, which has a multitude of gas outlet openings through which the gases can flow into the process chamber. The gas outlet plate acts as a plasma electrode, which can be energized by a voltage source located outside the process chamber. A grounded plate located below the gas outlet plate acts as a counter electrode. The plasma is thus generated between the gas outlet plate and the counter electrode. To prevent the release of any gases, the gas outlet plate is designed to act as a counter electrode. To allow ions and electrons to enter the process chamber, several vertically stacked shielding plates are arranged between the counter electrode and the susceptor, each of which also has a multitude of gas outlet openings. The shielding plates adsorb the ions and reflect the electrons. From the DE 10 2011 056 589 A1 A CVD reactor is known with a gas inlet device designed as a showerhead, through which various gases can be fed into a process chamber bounded at the bottom by a heated susceptor. A thermally dec