Abstract: An ammonium fluoride gas may be used to form a protection layer for one or more interlayer dielectric layers, one or more insulating caps, and/or one or more source/drain regions of a semiconductor device during a pre-clean etch process. The protection layer can be formed through an oversupply of nitrogen trifluoride during the pre-clean etch process. The oversupply of nitrogen trifluoride causes an increased formation of ammonium fluoride, which coats the interlayer dielectric layer(s), the insulating cap(s), and/or the source/drain region(s) with a thick protection layer. The protection layer protects the interlayer dielectric layer(s), the insulating cap(s), and/or the source/drain region(s) during the pre-clean process from being etched by fluorine ions formed during the pre-clean process.

Abstract: An ammonium fluoride gas may be used to form a protection layer for one or more interlayer dielectric layers, one or more insulating caps, and/or one or more source/drain regions of a semiconductor device during a pre-clean etch process. The protection layer can be formed through an oversupply of nitrogen trifluoride during the pre-clean etch process. The oversupply of nitrogen trifluoride causes an increased formation of ammonium fluoride, which coats the interlayer dielectric layer(s), the insulating cap(s), and/or the source/drain region(s) with a thick protection layer. The protection layer protects the interlayer dielectric layer(s), the insulating cap(s), and/or the source/drain region(s) during the pre-clean process from being etched by fluorine ions formed during the pre-clean process.

Abstract: A cascade refrigeration system includes first and second cooling devices. The first cooling device includes a first compressor, a condenser, an expansion device, an evaporator having first and second passages independent from and not communicating with each other, and a first conduit interconnecting the first compressor, the condenser, the expansion device and the first passage. The second cooling device includes a second compressor, a heat exchanger, and a second conduit interconnecting the second compressor, the second passage and the heat exchanger. A circulation switching device includes a switching mechanism connected to the first conduit downstream of the condenser and upstream of the expansion device.

Abstract: An evaporator includes a casing and a plurality of circulation units disposed on the casing. Each of the circulation units includes a flow path formed in the casing, an inlet formed in the casing for entry of one of refrigerants into the casing and fluidly communicating with the flow path, and an outlet formed in the casing spaced apart from the inlet for exit of the one of the refrigerants out the casing and fluidly communicating with the flow path. The circulation units are independent from each other and do not fluidly communicate with each other.

Abstract: A cascade refrigeration system includes first and second cooling devices. The first cooling device includes a first compressor, a condenser, an expansion device, an evaporator having first and second passages independent from and not communicating with each other, and a first conduit interconnecting the first compressor, the condenser, the expansion device and the first passage. The second cooling device includes a second compressor, a heat exchanger, and a second conduit interconnecting the second compressor, the second passage and the heat exchanger. A circulation switching device includes a switching mechanism connected to the first conduit downstream of the condenser and upstream of the expansion device.

Abstract: An evaporator includes a casing and a plurality of circulation units disposed on the casing. Each of the circulation units includes a flow path formed in the casing, an inlet formed in the casing for entry of one of refrigerants into the casing and fluidly communicating with the flow path, and an outlet formed in the casing spaced apart from the inlet for exit of the one of the refrigerants out the casing and fluidly communicating with the flow path. The circulation units are independent from each other and do not fluidly communicate with each other.