Abstract: A semiconductor device including a substrate with a first trench, a first insulation liner on inner flanks of the first trench, and a second insulation liner on inner flanks of a first sub trench, the first insulation trench defined by the first insulation liner in the first trench, a top level of the second insulation liner that adjoins the inner flanks of the first sub trench in a direction perpendicular to a top surface of the substrate being different from the top surface of the substrate outside the first trench, may be provided.

Abstract: Disclosed is a clothes dryer comprising a drum rotatably disposed in a body; and a roller disposed below the drum, and configured to support the drum. The roller is mounted to a roller shaft by a ball bearing, and a contact portion of an outer circumferential surface of the roller contacting the drum is formed to be flat.

Abstract: A dryer control method includes: a first dry step of drying a dry item with strong hot wind while tumbling a drum in which the dry item is placed; and a second dry step of drying the dry item with mild hot wind while tumbling the drum. Because the dry process is repeatedly performed on the dry item according to a proposed dry algorithm, the dry item made of wool fiber can be prevented from being shrunken or creased in the dry process.

Abstract: A dryer control method includes: a hot wind supply step in which hot wind is supplied to the dry items accommodated within the drum; an intermediate dry step in which the dry items are cooled and a hot wind supply to the cooled dry items is resumed; and a cooling step in which the hot wind supply is stopped and the dry items are cooled. Because the dry step is repeatedly performed on a dry item made of polyester fiber at short time intervals according to a proposed algorithm, a shrinkage of the dry item made of polyester fiber that may be otherwise generated in a general dry step can be prevented.

Abstract: Disclosed is a clothes dryer comprising a drum rotatably disposed in a body; and a roller disposed below the drum, and configured to support the drum. The roller is mounted to a roller shaft by a ball bearing, and a contact portion of an outer circumferential surface of the roller contacting the drum is formed to be flat.

Abstract: A dryer control method includes: a first dry step of drying a dry item with strong hot wind while tumbling a drum in which the dry item is placed; and a second dry step of drying the dry item with mild hot wind while tumbling the drum. Because the dry process is repeatedly performed on the dry item according to a proposed dry algorithm, the dry item made of wool fiber can be prevented from being shrunken or creased in the dry process.