The present invention provides a process for the
production of a semiconductor device comprising a semiconductor
element provided on a printed circuit board with a plurality of
connecting electrode portions provided interposed therebetween,
the gap between said printed circuit board and said
semiconductor element being sealed with an underfill resin
layer. In accordance with the present invention, (1) the
underfill resin layer is formed by melting a lamellar solid
resin provided interposed between said printed circuit board
and said semiconductor element, and (2) the lamellar solid
resin provided interposed between said printed circuit board
and said semiconductor element is heated for a predetermined
period of time until the temperature of the solid resin layer
reaches a predetermined range where the two components are
connected to each other under pressure under the following
conditions (X) and (Y):
 (X) Supposing that the initial residual heat of reaction of
the solid resin before heating is 100% as determined by a
differential scanning calorimeter (DSC), the residual heat of
reaction thereof is not more than 70% of the initial residual
heat of reaction; and (Y) The temperature of the semiconductor element is
predetermined higher than that of the printed circuit board,
and the difference in temperature between them is not less than
50°C. In this manner, a production process which facilitates the
resin sealing of the gap between the semiconductor element and
the board and thus can inhibit warpage of the entire
semiconductor device and a semiconductor device having an
excellent reliability can be provided. In the present
invention, the use of a sheet-like underfill material which
gives an underfill resin layer having an elastic modulus in
tension at 25°C of from 300 to 15,000 MPa when hardened can
provide a semiconductor device which exerts an excellent effect
of relaxing the stress on the semiconductor element, printed
circuit board and connecting electrode portions and thus
exhibits a high reliability.

Manufacture of semiconductor device

Light source apparatus for endoscope

PURPOSE:A sefmiconductor substrate provided with a nitrified film is put into a mixed solution of hydrogen peroxide and sulphuric acid, and chemically and physically treated after the nitrified film has been changed in quality in that solution. On doing this, it becomes possible to remove the nitrified film only, or control the thickness of the film. CONSTITUTION:A semiconductor substrate provided with a nitrified film is put into a mixed solution of hydrogen peroxide and sulphuric acid, and chemically and physically treated; e.g., etching and heating treatments, after the nitrified film has been changed in quality in the solution. For instance, after an oxidized field film 2 is formed on a silicon substrate 1 by the selective oxidizing method, using a silicon nitrified film the substrate is put into a mixed solution of hydrogen peroxide (concentration of 30%) and sulphuric acid (concentration of 96%) in the ratio of 1:1; heated for 30 minutes on a heated plate at 400 deg.C where the nitrified film used at the time of selective oxidization is changed in quality; then stripped of the nitride by etching the substrate with hydrofluoric water. Since the speed for etching the film changed in quality is greater than those for the silicon surface and the oxidized film, it is made possible to remove the nitrified film only or control the thickness of the film.

Process for manufacturing semiconductor substrate

PURPOSE:To shorten the time for forming a vapor deposited film and to prevent the generation of splashes by boiling and bumping by dividing the inside of a boat as an evaporating source by a partition plate having an aperture along the bottom plate surface thereof to a molten sample storing part and a molten sample evaporating part. CONSTITUTION:The central recess of a flat plate 1 is partitioned by the partition plate 4 to the molten sample storing part 2a and the molten sample evaporating part 2b. The bottom plate 5 is formed thin in the storing part 2a and thick in the evaporating part 2b and is so inclined as shown in the figure that the molten sample flows thereon. The partition plate 4 has the construction to allow the molten sample in the storing part 2a to flow along the bottom plate 5; for example, said plate is a mesh plate, etc. A material to be evaporated is filled into the storing part 2a and a voltage is impressed between flat plates 3 and 3', then the bottom plate 5 is so heated as to have the temp. gradient from the thick part to the thin part thereof. The temp. enough to allow the molten sample to complete the evaporation before arriving at the lowermost part of the evaporating part is attained in the evaporating part 2b when the bottom plate part of the storing part 2a is heated to the temp. enough to melt the sample. Since the molten sample is in the form of a liquid film, the sample is extremely liable to evaporate.

Evaporating device for vacuum deposition

Nonwoven fabric and molded body thereof

Piston for internal combustion engine

Internal combustion engine especially diesel engine

A piston for internal combustion engines, especially Diesel engines, which is equipped with a mantle connecting the piston head with the piston foot and which by means of this foot is pivotally connected to a gudgeon pin bearing of a connecting rod. Within the region of the gudgeon pin bearing there is provided at least one guiding surface for a coolant and/or lubricant sprayed from a crankcase chamber of the internal combustion engine against the piston. The coolant and/or lubricant are directed relative to the gudgeon pin bearing in such a way that the coolant and/or the lubricant carry out a flow around the gudgeon pin bearing while simultaneously flowing against the foot of the piston as well as against the gudgeon pin bearing.

Erusubetsuto Ruutobuitsuhi

Papers

Piston for internal combustion engine

Internal combustion engine especially diesel engine

Piston for internal combustion engine* especially for diesel engine

Cylinder block for reciprocating piston type internal combustion engine

Piston mechanism for reciprocal piston type internal combus-tion engine