Cover part, process gas diffusing and supplying unit, and substrate processing apparatus

A showerhead, provided in a plasma processing apparatus for plasma etching a substrate, for supplying a processing gas to a processing chamber comprising:

• a main body;
• an opening configured to introduce the processing gas into the internal space;
• a plate supported by the main body, an internal space formed between a supporting portion of the main body and the plate, the plate including gas supply holes through which the processing gas is supplied into the processing chamber,
• wherein the internal space communicates with the opening and directly communicates with the gas supply holes, and a height of the internal space is equal to or greater than 8 mm so that the processing gas discharged from the opening is diffused to the internal space and is uniformly supplied through the gas supply holes, and
• wherein the internal space is in the shape of a rectangular parallelopipedon, the height of the rectangular parallelopipedon is ε, a width of the rectangular parallelopipedon is ω, a length of a space defined by a plane (i) and a plane (i−1) in the rectangular parallelopipedon is L, where the plane (i) and the plane (i−1) are perpendicular to a length direction of the rectangular parallelopipedon, pressures exerted on the plane (i) and the plane (i−1) are Psi and Ps(i−1), respectively, a viscosity coefficient is μ, a conductance Csi with regard to a gas flow direction in the space defined by the plane (i) and the plane (i−1) is expressed by the following:
• Csi=ε3ω/12 μL·(Psi+Ps(i−1))/2, and
• a flow rate Qsi of the gas flowing through the space defined by the plane (i) and the plane (i−1) is expressed by the following:
• Qsi=Csi(Psi−Ps(i−1)).

A plasma processing apparatus for plasma etching a substrate comprising:

• a processing chamber configured to accommodate the substrate;
• a showerhead configured to supply a processing gas to the processing chamber;
• a susceptor serving as a lower electrode configured to mount the substrate;
• at least one processing gas introducing pipe configured to introduce the processing gas into the showerhead;
• and
• a gas exhaust pipe connected to a gas exhaust unit to perform vacuum exhaust of the processing chamber,
• wherein the showerhead includes:
• a main body;
• an opening configured to introduce the processing gas into the internal space;
• a plate supported by the main body, an internal space formed between a supporting portion of the main body and the plate, the plate including gas supply holes through which the processing gas is supplied into the processing chamber;
• and
• a shielding portion which is disposed within the internal space and has a surface facing the opening,
• wherein the internal space communicates with the opening and directly communicates with the gas supply holes, and at least a portion of the gas supply holes is located right below the shielding portion and a height of the internal space is equal to or greater than 8 mm so that the processing gas discharged from the opening is diffused to the internal space and is uniformly supplied through the gas supply holes, and
• wherein the internal space is in the shape of a rectangular parallelopipedon, the height of the rectangular parallelepipedon is ε, a width of the rectangular parallelopipedon is ω, a length of a space defined by a plane (i) and a plane (i−1) in the rectangular parallelopipedon is L, where the plane (i) and the plane (i−1) are perpendicular to a length direction of the rectangular parallelopipedon, pressures exerted on the plane (i) and the plane (i−1) are Psi and Ps(i−1), respectively, a viscosity coefficient is μ, a conductance Csi with regard to a gas flow direction in the space defined by the plane (i) and the plane (i−1) is expressed by the following:
• Csi=ε3ω/12 μL·(Psi+Ps(i−1))/2, and
• a flow rate Qsi of the gas flowing through the space defined by the plane (i) and the plane (i−1) is expressed by the following:
• Qsi=Csi(Psi−Ps(i−1)).