Patent ID: 8955579
Filing Date: 2015-02-17
Classification: F25B,F28F,H01J,H01L

Abstract:
1. A plasma processing apparatus which generates a plasma using a process gas introduced inside a vacuum processing chamber, and which processes a surface of a sample to be processed on a sample placement surface of a sample stage disposed inside the vacuum processing chamber, the apparatus comprising: a refrigerant channel circularly disposed in the sample stage under the sample placement surface, and a refrigerant supply port and a refrigerant outlet port which communicate with the refrigerant channel and are located in the sample stage, with the refrigerant flowing into the refrigerant channel through the refrigerant supply port and flowing out of the refrigerant channel through the refrigerant outlet port; a refrigeration cycle comprising the refrigerant channel in the sample stage, a compressor, a condenser and an expansion valve which are connected in this order, the refrigerant channel operating as an evaporator; a carburetor provided between the inlet of the compressor and the refrigerant outlet port on the refrigeration cycle which completely evaporates the refrigerant from the refrigerant outlet port which communicates with the refrigerant channel; and a controller which controls the operation of the refrigeration cycle, wherein the refrigerant channel has at least one of a portion in which the cross section area of the refrigerant channel is increasing, a portion in which the cross section area of the refrigerant channel is decreasing, and a portion in which the cross section area of the refrigerant channel is increasing and thereafter decreasing, and the refrigerant flows through said at least one of a portion in which the cross section area of the refrigerant channel is increasing, a portion in which the cross section area of the refrigerant channel is decreasing, and a portion in which the cross section area of the refrigerant channel is increasing and thereafter decreasing, with changing a rate of gas and liquid of the refrigerant; and wherein the controller adjusts the operation of the refrigeration cycle so that the refrigerant in the refrigerant channel is kept in a gas-liquid two-phase state of the refrigerant, and adjusts the dry degree of the refrigerant in the gas-liquid two-phase state inside the refrigerant channel by controlling an operation of the compressor, so that a heat transfer coefficient of the refrigerant is at its maximum at a position of the refrigerant channel where a cross section area of the refrigerant channel is at its maximum.