JPS61125049A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To prevent the thinning of wirings and wire breakdown at the stepped part on the surface and to make it possible to form the device by a simple processes, by applying an insulating organic film so that the stepped part on the surface of a substrate and a field plate in a semiconductor integrated circuit device having a high withstanding voltage elements are embedded and the surface becomes flat. CONSTITUTION:A field plate 2 is provided in a single crystal silicon island 1, which is supported by a polycrystalline silicon supporting layer 7 and isolated by a dielectric body. In this high withstanding voltage element, an insulating film 5, which is formed beneath the field plate in order to obtain sufficient field plate effect, is made thin. Meanwhile, a thick insulating film 5' is required so that local deterioration of the withstanding voltage is not yielded beneath a metal wiring layer 3. A stepped part formed by the thick insulating film 5' and the thin insulating film 5 and the field plate 2 are embedded by an insulating organic film 4. The surface is made flat. Then, a through hole reaching the field plate is formed in the insulating organic film 4. The metal wiring layer 3 is formed on the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of practical application] The present invention relates to a semiconductor integrated circuit device, and more particularly to the structure of a surface protective film of a semiconductor integrated circuit device having a high breakdown voltage element.

[Conventional technology]

Conventionally, in this type of semiconductor integrated circuit device, wiring sections connecting elements formed on dielectrically isolated Crycon single-crystal islands are composed of floating insulating films, and are also equipped with field plates to improve the breakdown voltage characteristics of the elements. A device is formed. However, it is necessary to form a thin insulating film under the field plate.

[Problem that the invention seeks to solve]

The surface of the element of the semiconductor integrated circuit device having the above-mentioned structure inevitably has a high level difference, and the wiring formed thereon is often disadvantageous in that it becomes thin due to the level difference and breaks.

Therefore, in order to prevent this, it is necessary to add special processes such as removing the corners of the stepped portion or applying a different material to smooth out the steps, which complicates the process, lowers the yield, and reduces manufacturing efficiency. This had the disadvantage that it was an expensive Gyuji body device.

It is an object of the present invention to eliminate the above-mentioned drawbacks, eliminate thinning and disconnection of wiring at surface step portions, and provide a high-voltage semiconductor integrated circuit using a dielectric separation method that can be formed by a simple process and has a high yield and high quality. shall be.

In a semiconductor integrated circuit device configured by forming a high-voltage element with a field plate on a single-crystal island, an insulating organic film is applied to embed the stepped portion of the substrate surface and the field plate, and to make the surface flat. and,
It is constructed by having a through hole formed in the insulating organic film and reaching the field plate, and a metal wiring provided on the insulating organic film.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of an embodiment of the present invention.

As shown in FIG. 1, a high breakdown voltage element is formed on a dielectrically isolated silicon single crystal island 1 held by a polycrystalline silicon support layer 7, and an element junction 6 is formed by ordinary impurity diffusion.

Next, a thin oxide film 5 is formed, holes are opened for the device junctions, and then the field plate 2 is formed. In the case of semiconductor integrated circuit devices that require high withstand voltage characteristics, it is well known that the characteristics can be improved by installing a field plate 2. Made thin to obtain a plate effect.

On the other hand, a floating insulating film 5' is required under the metal wiring layer 3 which extends beyond the silicon single crystal island 1 and is connected to other elements to prevent local voltage deterioration. In the present invention, the step portion formed by the thick insulating film 5' and the thin insulating film 5 is filled with the low step part including the field plate 2 with an insulating organic film 4 formed by a coating method, and the coating conditions are Flatten the surface by selection.

In addition, if liquid polyimide or the like is used as the insulating organic film, it is recommended to appropriately select the viscosity of the material and the coating conditions to form a low step and a field plate 2, as shown in Figure 2. It becomes possible to achieve a controlled embedding state due to the surface tension effect of the stepped portion while embedding, and it is possible to facilitate the formation of through holes in the next step.

Next, as shown in FIG. 1, in the insulating organic film thus applied, through holes are formed for connection to a field plate having a wide area installed on the high voltage element.

Next, a metal wiring layer 3 is formed by attaching a metal wiring material to the surface and patterning it. With the above steps, this embodiment is completed.

As explained above, in this embodiment, through holes can be easily created on the field plate in the formed insulating organic film, and devices can be connected by reducing the effect of steps caused by the insulating organic film. The metal wiring layer 3 should be connected to other elements through high step portions without local voltage deterioration, and the field plate embedded in the insulating organic film should be fully effective through the thin insulating film. Can be done.

〔Effect of the invention〕

As explained above, according to the present invention, thinning and disconnection of wiring at surface step portions can be eliminated, a semiconductor integrated circuit can be formed by a simple process, has a high yield, and has a high breakdown voltage using a high-quality dielectric separation method. You can get the equipment.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view of a part of the manufacturing process of the embodiment shown in FIG. 1, showing the coating state of an insulating organic film. 1...Silicon single crystal island, 2...Field plate, 3...Metal wiring layer, 4...
... Insulating organic film, 5 ... Thin insulating film, 5
/...Thick insulating film, 6...Element junction, 7...Polycrystalline silicon support layer. Agent Patent Attorney Susumu Uchihara, Nia , -, ＼
.

Claims (1)

[Claims] In a semiconductor integrated circuit device configured by forming a high breakdown voltage element with a field plate on a silicon single crystal island formed on a substrate by a dielectric separation method, the stepped portion of the substrate surface and the field plate are embedded and the surface is It is characterized by having an insulating organic film coated so as to be flat, a through hole formed in the insulating organic film and reaching the field plate, and a metal wiring provided on the insulating organic film. Semiconductor integrated circuit device.