A power semiconductor device includes a power transistor including a plurality of transistor cells on a semiconductor die. At least some of the transistor cells are inhomogeneous by design so that the number of current filaments in the transistor cells with reduced local current density increases and fewer transient avalanche oscillations occur in the power transistor during operation.

There is provided a trench-gate type semiconductor device that can prevent breakdown of a gate insulating film caused by a displacement current flowing into a protective diffusion layer at a portion of a trench underlying a gate electrode at a turn-off time and simultaneously improves a current density by narrowing a cell pitch. The semiconductor device has a gate electrode 7 embedded into a trench 5 penetrating a base region 3. The gate electrode 7 is disposed into a lattice shape in a planar view, and a protective diffusion layer 13 is formed in a drift layer 2a at the portion underlying thereof. At least one of blocks divided by the gate electrode 7 is a protective contact region 20 on which the trench 5 is entirely formed. A protective contact 21 for connecting the protective diffusion layer 13 at a bottom portion of the trench 5 and a source electrode 9 is disposed on the protective contact region 20.

A switching loss is prevented from being deteriorated by suppressing increase in a gate capacitance due to a cell shrink of an IE type trench gate IGBT. A cell formation region is configured of a linear active cell region, a linear hole collector cell region, and a linear inactive cell region between them. Then, upper surfaces of the third and fourth linear trench gate electrodes which are formed so as to sandwich both sides of the linear hole collector cell region and electrically connected to an emitter electrode are positioned to be lower than upper surfaces of the first and second linear trench gate electrodes which are formed so as to sandwich both sides of the linear active cell region and electrically connected to a gate electrode.

A semiconductor device includes a plurality of trench gates provided abreast in a semiconductor substrate; an interlayer insulation film having opening from which a part of a front surface of the semiconductor substrate is exposed; and contact plugs provided in the openings. The interlayer insulation film comprises a plurality of first portions, each of which covers a corresponding one of the trench gates, and a plurality of second portions, each of which is provided between adjacent first portions and along a direction intersecting with the first portions. The openings are provided at an area surrounded by the first portions and the second portions, a length of the openings in a direction along the first portions is shorter than a length of the openings in a direction along the second portions intersecting with the first portions.

An embodiment of a semiconductor device comprises a first load terminal contact area at a first side of a semiconductor body. A second load terminal contact area is at a second side of the semiconductor body opposite to the first side. A control terminal contact area is at the second side of the semiconductor body. An isolation structure extends through the semiconductor body between the first and second sides. The isolation structure electrically isolates a first part of the semiconductor body from a second part of the semiconductor body. A first thickness of the first part of the semiconductor body is smaller than a second thickness of the second part of the semiconductor body.

In an IGBT portion, a first gate electrode is provided in a first trench via a first gate insulating film. A thickness of a first gate insulating film lower portion is thicker than a thickness of a first gate insulating film upper portion, whereby a width of a mesa portion between adjacent first trenches is narrower at a portion of a collector side than at an emitter side. In a diode portion, a second gate electrode is provided inside a second trench via second gate insulating film. A width of the second trench is uniform along a depth direction or narrows from the emitter side toward the collector side. Widths of the second trench are narrower than a sum of a width of the first trench lower portion and the thickness of the first gate insulating film lower portion of both side walls of the first trench lower portion.

Properties of a semiconductor device are improved. A semiconductor device is configured so as to have a protective film provided over an interconnection and having an opening, and a plating film provided in the opening. A slit is provided in a side face of the opening, and the plating film is also disposed in the slit. Thus, the slit is provided in the side face of the opening, and the plating film is also grown in the slit. This results in a long penetration path of a plating solution during subsequent formation of the plating film. Hence, a corroded portion is less likely to be formed in the interconnection (pad region). Even if the corroded portion is formed, a portion of the slit is corroded prior to the interconnection (pad region) at a sacrifice, making it possible to suppress expansion of the corroded portion into the interconnection (pad region).

A performance of a semiconductor device is improved. A semiconductor device includes two element portions and an interposition portion interposed between the two element portions. The interposition portion includes a p-type body region formed in a part of a semiconductor layer, the part being located between two trenches, and two p-type floating regions formed in two respective parts of the semiconductor layer, the two respective portions being located on both sides of the p-type body region via the two respective trenches. A lower end of the p-type floating region is arranged on a lower side with reference to a lower end of the p-type body region.

A method of manufacturing an insulated gate type switching device includes forming a gate trench that has a first portion with a first width in a first direction and a second portion with a second width in the first direction, the second width being wider than the first width. In an oblique implantation, second conductivity type impurities are irradiated at an irradiation angle inclined around an axis orthogonal to the first direction. The first width, the second width, and the irradiation angle are set such that the second conductivity type impurities are suppressed, at a first side surface of the first portion, from being. implanted into a part below a lower end of a second semiconductor region, and at a second side surface of the second portion, the impurities are implanted into the part below the lower end of the second semiconductor region.

An IGBT manufacturing method is provided. The IGBT has an n-type emitter region, a p-type top body region, an n-type intermediate region, a p-type bottom body region, an n-type drift region, a p-type collector region, trenches penetrating the emitter region, the top body region, the intermediate region and the bottom body region from an upper surface of a semiconductor substrate and reaching the drift region, and gate electrodes formed in the trenches. The method includes forming the trenches on the upper surface of the semiconductor substrate, forming the insulating film in the trenches, forming an electrode layer on the semiconductor substrate and in the trenches after forming the insulating film, planarizing an upper surface of the electrode layer, and implanting n-type impurities to a depth of the intermediate region from the upper surface side of the semiconductor substrate after planarizing the upper surface of the electrode layer.