Even when a stiffener is omitted, the semiconductor device which can prevent the generation of twist and distortion of a wiring substrate is obtained. As for a semiconductor device which has a wiring substrate, a semiconductor chip by which the flip chip bond was made to the wiring substrate, and a heat spreader adhered to the back surface of the semiconductor chip, and which omitted the stiffener for reinforcing a wiring substrate and maintaining the surface smoothness of a heat spreader, a wiring substrate has a plurality of insulating substrates in which a through hole whose diameter differs, respectively was formed, and each insulating substrate contains a glass cloth.

A pressing group for a sintering press to carry out sintering of electronic components on a substrate has a multi-stem cylinder having a front head and a rear head together delimiting a compression chamber. In the front head pressing stems are slidingly supported, parallel and independent from each other, the rear ends of the pressing stems protruding into the compression chamber. In the compression chamber, an actuating flat gasket extends over the rear ends of the pressing stems. The actuating flat gasket is fixed to the front head by an anchoring frame engaging a peripheral portion of the actuating flat gasket, the anchoring frame being completely housed in the compression chamber so that the pressurized fluid also acts on the anchoring frame.

Even when a stiffener is omitted, the semiconductor device which can prevent the generation of twist and distortion of a wiring substrate is obtained. As for a semiconductor device which has a wiring substrate, a semiconductor chip by which the flip chip bond was made to the wiring substrate, and a heat spreader adhered to the back surface of the semiconductor chip, and which omitted the stiffener for reinforcing a wiring substrate and maintaining the surface smoothness of a heat spreader, a wiring substrate has a plurality of insulating substrates in which a through hole whose diameter differs, respectively was formed, and each insulating substrate contains a glass cloth.

The inventive concept relates to an apparatus for manufacturing a semiconductor package and a method of manufacturing a semiconductor package. According to embodiments, the method of manufacturing a semiconductor package may include preparing a substrate including upper conductive pads on an upper surface of the substrate, preparing a first semiconductor chip including first solder balls, wherein a first dielectric layer covering sidewalls of the first solder balls is on a lower surface of the first semiconductor chip, disposing the first semiconductor chip on the substrate such that the first solder balls are on the upper conductive pads, and bonding the first solder balls to the upper conductive pads by applying an alternating current electric field to the first dielectric layer.