JP2016152343A - Semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a transformer built-in element which has a fine structure and stable characteristics.SOLUTION: In a semiconductor device, a silicon oxide film is formed on a silicon substrate and a plurality of coils are embedded in the silicon oxide film. Insulation between coils are performed by the silicon oxide film. Since this structure can be manufactured in a semiconductor process, in comparison with an element formed by MEMS in the past, a fine structure can be achieved. In addition by forming a thermal oxide film on the silicon substrate and forming the silicon oxide film made from TEOS on the thermal oxide film, a transformer built-in element which has less stress in the film and stable characteristics can be formed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a structure of a built-in transformer element that can realize a fine structure because it uses a semiconductor process and has stable characteristics.

In recent years, with the development of processing technology, gate drivers with built-in insulation transformers using MEMS technology have been developed.

JP 2008-61236 A

However, when a transformer built-in element is made by a processing technique such as MEMS, it is difficult to make the structure finer and to obtain stable characteristics, such as bonding a coil formed on a substrate to an insulating substrate for insulation.
The present invention relates to a structure for solving the above problems.

In order to solve the above-described problems, the present invention has the following configurations.
The semiconductor device of the present invention is formed on a silicon substrate, and a plurality of coils constituting the transformer are each embedded and insulated in a silicon oxide film formed on the silicon substrate.

The silicon oxide film in which the plurality of coils are embedded is preferably a silicon oxide film formed using TEOS (tetraethoxysilane) as a source gas. Further, it is desirable that the thickness of the silicon oxide film between the coils to be insulated is 0.5 μm to 30 μm, and the total thickness of the silicon oxide film is 100 μm or less.
A silicon oxide film using TEOS as a raw material is relatively flexible and has a feature that an embedded coil is hardly subjected to stress. In addition, by using the above film thickness, an element having good and stable characteristics between the coils can be produced.

The coil is formed from a wiring material such as aluminum, copper, or polysilicon. The thickness of the wiring is 0.5 μm to 5 μm, the wiring width is 10 μm or less, and the distance between the lateral metals is 5 μm or less.

According to the present invention, a transformer built-in element having a fine structure and obtaining good characteristics can be formed.

It is a top view of the transformer containing element concerning Example 1 of the present invention. 1 is a cross-sectional view of a transformer-containing element according to Example 1 of the present invention.

Hereinafter, the structure which becomes embodiment of this invention is demonstrated.

The transformer built-in element according to the first embodiment will be described. An upper coil and a lower coil constituting the transformer are embedded in a silicon oxide film and insulated.
The silicon oxide film is preferably a TEOS-based silicon oxide film having a relatively flexible film quality and capable of obtaining stable characteristics without applying stress to the coil. In addition, it is desirable that a thermal oxide film is present under the TEOS silicon oxide film, which can further alleviate stress on the TEOS silicon oxide film received from the silicon substrate. In order to alleviate the stress, it is desirable that the relation of b> a is satisfied, where b is the thickness of the silicon oxide film and a is the thickness of the thermal oxide film.

1, 4, 6 Silicon oxide film 2, upper coil 3, shield electrode 5, lower coil 7, silicon substrate 8, electrode pad.
9, wire 10, thermal oxide film

Claims (3)

A semiconductor device comprising a plurality of coils embedded in a silicon oxide film formed on a silicon substrate and insulated by the silicon oxide film.
The silicon oxide film is formed of a silicon oxide film using TEOS (tetraethoxysilane) as a raw material, and an oxide film thickness between a plurality of coils is 0.5 μm to 30 μm. Semiconductor device.
  The thermal oxide film exists between the silicon oxide film and the silicon substrate, wherein b> a where b is the thickness of the silicon oxide film and a is the thickness of the thermal oxide film. 2. The semiconductor device according to 2.

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