Abstract: A plasma etching apparatus may include a first source electrode, a first bias electrode, and a second bias electrode configured to generate a plasma by supplying energy to a process gas injected into a chamber; and a controller. The controller may be configured to supply a first high-frequency RF power, a first low-frequency RF power, and a second low-frequency RF power to the chamber during a first period from a first time to a second time; ramp down and turn off the first high-frequency RF power to the chamber during a second period from the second time to a third time; and ramp down and turn off the first low-frequency RF power to the chamber during a third period from the second time to a fourth time different from the third time. The third period may be smaller than ½ of the first period and greater than the second period.

Abstract: A package and a package assembly for a power device having a high operation voltage and impulse voltage are provided. The package assembly for a power device comprises an assembly wherein the power device is encapsulated and electrically connected to a lead protruding outside the package, and an isolation spacer filling a clearance distance between the package and a heat sink attached to the package.

Abstract: A package and a package assembly for a power device having a high operation voltage and impulse voltage are provided. The package assembly for a power device comprises an assembly wherein the power device is encapsulated and electrically connected to a lead protruding outside the package, and an isolation spacer filling a clearance distance between the package and a heat sink attached to the package.

Abstract: An Fe-Mn vibration damping alloy steel having a mixture structure of .epsilon., .alpha.' and .gamma.. The alloy steel consists of iron, manganese from 10 to 24% by weight and limited amounts of impurities. The alloy steel is manufactured by preparing an ingot at a temperature of 1000.degree. C. to 1300.degree. C. for 12 to 40 hours to homogenize the ingot and hot-rolling the homogenized ingot to produce a rolled alloy bar or plate, performing solid solution treatment on the alloy steel at 900.degree. C. to 1100.degree. C. for 30 to 60 minutes, cooling the alloy steel by air or water, and cold rolling the alloy steel at a reduction rate of greater than 0% and below 30% at around room temperature.

Abstract: A vibration damping alloy has a mixed structure of martensite and austenite. The alloy steel is iron-based to which 14-22% by weight of manganese is added. The vibration damping alloy is manufactured by mixing electrolytic iron and manganese in a molten state. The molten mixture, containing 14-22% of manganese with the remainder of iron, is cast as an ingot. The ingot is homogenized at 1000.degree.-1300.degree. C. for 20-40 hours and then hot rolled at 900.degree.-1100.degree. C. for 20 minutes to 90 minutes. The ingot is cooled with air or water.