JPS58134466A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To alleviate the concentration of an electric field in a semiconductor device by plasma treating with 0 an oxidized film as being hydrophilic at the peripheral edge during the formation of a P type layer surrounding at an interval the element part of an N type semiconductor substrate, forming an oblique at the peripheral edge of a window at the time of opening the window at the oxidized film, and forming electrodes. CONSTITUTION:When a P type layer 2 is formed to surround the element of an N type substrate 1, an oxidized film is formed. The surface of the layer 1 and its peripheral edge are plasma treated with 0, thereby forming the oxidized film in a hydrophilic state. A resist mask is covered on the oxidized film 3, and an etching is performed. In this manner, since the photoresist is hydrophobic and does not have adhesive to the hydrophilic oxidized film, an etchant is impregnated to underneath the mask, with the result that the film 3 is inclined at the peripheral edge of the window. When an electrode 4 is attached onto the film, a depletion layer 6 becomes extremely smooth on the part A, thereby eliminating the concentration of an electric field and improving the withstand voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a high voltage semiconductor device.

Conventionally, in order to increase the breakdown voltage of a semiconductor device, a so-called guard ring, which is provided on a semiconductor substrate and surrounds a nine-element section, has been used.

FIG. 1 is a sectional view of an example of a conventional semiconductor device.

A P-type region 2t surrounding an element part (not shown) of an N-type semiconductor substrate 1 is provided, an oxide film 3 formed on the surface of the semiconductor substrate is selectively etched to open a contact window t, and an electrode is formed using aluminum or polysilicon.゛4t-form.

Now, when a reverse bias is applied between the semiconductor substrate l and the electrode 4, the depletion layer 6 expands as shown by the broken line 5. depletion layer 6
spreads uniformly under the surface of the semiconductor substrate below the electrode 4. Therefore, there is a drawback that the electric field is concentrated at the part A in the figure and the withstand voltage is not sufficiently large.

FIG. 2 is a sectional view of another example of a conventional semiconductor device.

After forming the IKP type region 2t on the semiconductor substrate, a nitride film is provided at the contact window and thermal oxidation is performed. As shown in FIG. QB, an oxide film 3 having a slope at the periphery of the contact window is obtained. Thereafter, the nitride film is removed and an electrode 4 is provided.

With such a structure, the depletion layer 6 becomes rounded and smooth in the portion A, making it difficult for electric field concentration to occur, contributing to an improvement in breakdown voltage. However, in order to realize this structure, the manufacturing process is long, including growing a nitride film after forming an oxide film, buttering the nitride film, thermal oxidation using the nitride film as a mask, and removing the nitride film. However, it not only requires an expensive process such as growing a nitride film, but also has the drawback that the electric field concentration in the A part cannot be sufficiently alleviated because the B part of the oxide film 3 is rounded.

The present invention provides a method for manufacturing a semiconductor device that eliminates the above-mentioned drawbacks, uses an easily implemented process, and improves breakdown voltage characteristics even when semiconductor substrates having the same resistivity are used.

This is what we provide.

The first step in the method for manufacturing a semiconductor device of the present invention is the front 1e of the first conductive conductor substrate on which the semiconductor element portion is formed.
A step of forming a second conductive cut region surrounding the hP conductor element portion at intervals, and an oxide film formed on the second conductive eL micro region and its periphery during the step of forming the second conductive region. a step of performing oxygen plasma treatment to make the surface hydrophilic; forming a photoresist mask on the surface of the oxide film on the semiconductor substrate and selectively etching the oxide film on the second conductivity type region; a step of simultaneously opening a contact window and slanting an oxide film around the contact window; a step of forming an electrode and an interconnection layer connected to the second conductivity type region through the contact window; The composition is confusing.

A second method of manufacturing a semiconductor device according to the present invention includes forming a second conductivity type region that surrounds the front d-pi semiconductor element portion of the first conductivity type conductor substrate, on which the semiconductor element portion is formed, at intervals; forming a second conductive guard ring that surrounds the second conductive type region at intervals; A step of performing oxygen plasma treatment to make the surface of the oxide film on the periphery hydrophilic, forming a photoresist mask on the surface of the oxide film on the semiconductor substrate, selectively etching the oxide film, and etching the surface of the oxide film on the guard ring. Consisting of the steps of: opening a contact window in the oxide film and simultaneously attaching an inclined tube to the oxide film around the cough contact window; and forming electrodes and wiring connected to the guard ring via the contact window. be done.

Next, one example of the present invention will be explained with reference to the drawings.

In the description of the actual 1tA example, the first conductivity type is ff1tN type and the second conductivity type is tF.

FIG. 3 is a sectional view for explaining the first embodiment FIJt of the present invention.

A P-type region 2t (not shown) of the N-type conductor substrate l (not shown) is provided on the P-type region 2. An oxide film is also generated on the P-type region 2 when the P-type region 2 is formed. and its periphery [
Oxygen plasma treatment is performed to make the oxide film surface hydrophilic. This can be achieved by performing oxygen plasma treatment at several hundred watts for several tens of seconds. Next, a photoresist is provided on the surface of the oxide film 30,
(Then, the oxide film 3 is etched to open a contact window. Since the photoresist is hydrophobic, it has poor adhesion to the plasma-treated hydrophilic oxide film. In this state, the oxide film When the etching is completed, the etching solution seeps under the photoresist and the etching progresses, resulting in oxidation [3] having a slope at the periphery of the contact window.An electrode 47 is then formed.

According to the above manufacturing method, since the oxide film 3 has an unrounded slope, the depletion layer 6 is very gently rounded at the portion A, the electric field strength is weakened, and the withstand voltage is extremely high.

Figure 4 shows #! of the present invention. FIG. 2 is a sectional view for explaining the actual M and Ut of FIG.

An element portion (not shown) of an N-type semiconductor substrate 1 is provided with a P-type region 2t surrounded by a spacing t and a P-type guard t surrounded by a further spacing. And the first real N for guard ring 7? ! Applying the same manufacturing method as I, forming an inclined surface on the oxide 3 around the contact window of the guard ring 7,
Electrode 4 is formed. The depletion layer 6 is A as in the first embodiment.
The parts are rounded and high pressure resistance is achieved.

As described in detail above, according to the present invention, a method for manufacturing a conductor Hk that achieves high voltage resistance by a method that can be easily carried out can be obtained, so that the effect is large.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an example of a conventional cattle conductor device, Fig. 2 is a sectional view of another conventional cattle conductor device, and Fig. 3 is a friend explaining the first fruit of the present invention. cross-sectional view, 4th
The figure is a sectional view for explaining the second embodiment J1gAUt of the present invention. l...N-type medium conductor substrate, 2...P-type region, 3...oxide film, 4...electrode, 6...
... Depletion layer, 7... Guard ring. Niji A Ya1 Figure 1 1 Koshirae 2 Figure 1 Figure 3 A 15 Figure 4

Claims (2)

[Claims] (1) A step of forming a second conductivity type region surrounding the semiconductor element portion at intervals, and a step of forming the second conductivity type region during the step of forming the second conductivity type region. A step of performing oxygen plasma treatment to make the surface of the oxide film formed on the 8I2 conductivity type region and its periphery water-soluble, and forming a photoresist mask on the surface of the oxide film on the semiconductor substrate to select the oxide film. etching to open a contact window T- in the oxide film on the second conductivity type region, and at the same time slope the oxide film at the periphery of the contact window; A method for manufacturing a semiconductor device, comprising the steps of forming subsequent electrodes and wiring. (2) A second conductivity type region that surrounds the semiconductor element part of the first conductivity type conductor substrate on which the semiconductor element part is formed at a distance, and a second conductivity type region that surrounds the scissors second conductivity region at a distance. Oxygen that makes the surface of the oxide film on the guard ring and its M4 edge hydrophilic among the oxide films formed during the step of forming the molded gum dog and the second conductive region and the guard ring forming step. A step of performing plasma treatment and forming a photoresist mask on the surface i1 of the oxide film on the semiconductor substrate, )! A step of selectively etching the trie oxide film to form a contact window in the oxide film on the guard ring and at the same time attaching the oxide film at the periphery of the contact window upwardly;
i! A method of manufacturing a semiconductor device, comprising the step of forming subsequent electrodes and wiring.