JPS63252425A - Manufacturing method of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application in the Cfrl Industry The present invention relates to a method for manufacturing a semiconductor device in which impurity diffusion layers of different conductivity types are formed on two different heads in the same semiconductor substrate.

[Summary of the invention]

The present invention is a method for manufacturing a semiconductor HFa, in which a silicon nitride film is formed on a semiconductor substrate, and impurities are implanted using the silicon nitride film buttered by photo-etching technology as a mask to improve the surface of the semiconductor substrate. By selectively oxidizing with a silicon nitride film and then implanting impurities using the oxide film as a mask, a semiconductor device is manufactured in which different impurity diffusion layers are formed in the semiconductor substrate.

[Conventional technology]

In the conventional manufacturing method of a semiconductor device, when forming different impurity diffusion layers such as a P well and an N well in a semiconductor substrate, as shown in FIG. 3, (a) an oxide film 301 is formed on the surface of a semiconductor substrate 302. , (b) After applying a photoresist 304 and removing part of the photoresist and part of the oxide film by a photoetching process, impurity ions are implanted. (c) Form an oxide film 306 again on the surface of the semiconductor substrate, (d) cover the photoresist 310, remove part of the photoresist and part of the oxide film, and then implant impurity ions. (e) Diffusion of the implanted impurity. A manufacturing method has been used in which different impurity diffusion layers are formed in a semiconductor substrate through the above steps.

[Problem that the invention seeks to solve]

However, the conventional manufacturing method described above requires two photoetching steps and an oxide film formation step to form different impurity diffusion layers, and the impurity is transferred to the semiconductor substrate using the photoresist and oxide film as a mask. was being injected.

That is, the problems with the conventional technique include, firstly, that it requires two photo-etching steps, so one
This requires a margin for alignment at every corner, which poses a problem in miniaturizing semiconductor devices.

Second, in order to form different impurity diffusion layers, two photo-etching steps and a step of forming an oxide film on the surface of the semiconductor substrate are required, which creates the problem that the process is complicated and the cost is high. was.

Therefore, in order to eliminate the above-mentioned drawbacks, the present invention has the following features:
By forming different impurity diffusion layers by utilizing the selective formation of an oxide film using a silicon nitride film,
Different impurity diffusion layers are formed in a self-aligned manner to miniaturize semiconductor devices.

Another purpose is to simplify the manufacturing process of a semiconductor device and reduce the cost of the semiconductor device.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes: a) forming a silicon nitride film on a semiconductor substrate or a semiconductor substrate on which a thin oxide film is formed;

b) A step of removing a portion of the silicon nitride film by photoetching and implanting impurities into the removed portion of the semiconductor substrate.

C) A step of selectively oxidizing the semiconductor substrate with the silicon nitride film and forming a thick oxide film on the portion where the silicon nitride film has been removed.

d) After removing the silicon nitride film, a step of implanting impurities into the semiconductor substrate in a portion where there is no thick oxide film.

e) Activating and diffusing the implanted impurity by heat treatment.

(Example〕 Examples of the present invention are described below.

As shown in (a) of FIG.
A silicon nitride film 101 is formed on the surface on which the silicon nitride film 03 is formed. A part of this silicon nitride film 101 is removed by photoetching technique, and as shown in FIG. 1(b), using the photoresist 104 and the silicon nitride film as a mask,
Impurity ions are implanted into the semiconductor substrate 102 . As shown in FIG. 1(C), when the photoresist is oxidized after removal, the parts of the substrate where there is no silicon nitride film 101 are selectively oxidized, and thick oxide lI2106 is formed on the parts where there is no silicon nitride film. It is formed. At this time, depending on the oxidation conditions,
The implanted impurity ions 105 are thermally diffused to form an impurity diffusion layer 107. After removing the silicon nitride film 101, impurity ions are implanted using a thick oxidized +1toe mask as shown in FIG. 1(d). Here, the impurity ions are implanted only in the thin part of the oxide film, that is, in the cylindrical part where the silicon nitride film was. As shown in FIG. 1(e), different impurity diffusion layers (107 and 1
09) is formed in a self-aligned manner.

As shown in the examples of the manufacturing method above, both the photoetching process and the thermal oxidation process are performed only once each, which is much simpler than the conventional manufacturing method, and different impurity diffusion methods are used. The accuracy of layer alignment is also improved compared to conventional technology, which requires two photo processes. Further, as shown in FIGS. 2(a) to 2(e), impurity implantation into the semiconductor substrate can be performed not only by ion implantation but also by thermal diffusion. As described above, by using the manufacturing technology of the present invention, different impurity diffusion layers can be formed in a self-aligned manner, and different ion species, different concentrations, and different diffusion depths can be formed at t! It was possible to form i diffusion layers in a simple process.

〔Effect of the invention〕

As described above, the advantage of the present invention is that when different impurity diffusion layers are formed, there is no need for an alignment margin in the photo-edding process 11 for forming the diffusion layers, unlike the prior art. Further, the process is simplified to one in the present invention, whereas the conventional photoetching process is carried out twice.

In this way, the manufacturing method of the present invention enables miniaturization of semiconductor devices,
We will emphasize the effects of reducing the manufacturing process to r5dlN, that is, reducing the cost of semiconductor devices and shortening delivery times.

[Brief explanation of drawings]

FIGS. 1A to 1C are diagrams showing step-by-step the method of manufacturing a semiconductor device of the present invention, taking as an example a case where an impurity diffusion layer is formed using ion implantation. FIGS. 2(a) to 2(e) show the method of manufacturing a semiconductor device of the present invention, taking as an example the case where an impurity diffusion layer is formed with different diffusion depths by ion implantation and thermal diffusion. Diagram showing the process step by step. FIGS. 3(a) to 3(e) show the process of forming different impurity diffusion layers using the conventional semiconductor device manufacturing method.
Figure shown. 101...Silicon nitride film 102...Semiconductor substrate 103...Thin silicon oxide film 104...Photoresist 105...Implanted impurity ions/110G...Thick silicon oxide film 107...Diffusion Impurity layer 1 108...Injected impurity ions/2100...Diffused impurity layer 2 201...Silicon nitride film 202...Semiconductor substrate 204...Photoresist 205...Injected impurity Ions 206... Thick silicon oxide film 207... Diffused impurity layer 1 209... Impurity layer implanted by thermal diffusion 2301... Thick silicon oxide 1) 1 302... Semiconductor substrate 304... Photoresist 1 305... Injected impurity ions 1306... Thick silicon oxide film 307... Diffused impurity layer 1 308... Injected impurity ions 2309... Diffused impurity layer 2 310... Photo Resist 2 Applicant: Seiko Epson Co., Ltd. 1121 2M Regular 3 Figure Procedure Amendment Teeth (Voluntary) May 1988 78 1. Indication of the Case Patent Application 2 filed on April 9, 1988. Title of the invention. Semiconductor device manufacturing method 3, relationship with the amended person case Applicant: 2-4-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo (236) Representative Director of Seiko Epson Corporation Hattori - Department 4, Agent: 104 Chuo, Tokyo Mogami Patent Office, Hattori Seiko Co., Ltd., 2-6-21, Kyobashi-ku (4654)
Patent Attorney Mogami! contact address
563-2111 extension 631-640 tn”h
'-u-'5, Symmetrical details of correction l! (Detailed Description of the Claim 1 Invention) Procedure Amendment 1: The Claims are amended as shown in the attached sheet. 2. 2nd line from the bottom of page 2 of the specification and 1st line of page 4 rLO
cO5J is corrected to "rLOcO5 (selective oxidation method)". 3. Insert the following sentence between the lines of the second page of the specification WS page 6. "Furthermore, the present invention is characterized by forming a field oxide film by LOGO3 (selective oxidation method) and utilizing the four parts formed between this field oxide film and the gate electrode. In other words, the substrate is selectively oxidized. By forming a field oxide film protruding above the substrate and forming a gate electrode with approximately the same height as the field oxide film, the insulating film formed on top of the gate electrode becomes a source/drain diffusion layer. By embedding a resist in the four parts and then removing the insulating film under the resist by reverse etching using the resist as a mask, the source and drain diffusions can be formed. The contact hole in which the lead wiring for establishing conduction with the layer is provided is reliably formed in a self-aligned manner.''

Claims (1)

[Claims] a) A step of forming a silicon nitride film on a semiconductor substrate or a semiconductor substrate on which a thin oxide film has been formed. b) A step of injecting impurities into the semiconductor substrate at a portion where a portion of the silicon nitride film has been removed by photo-etching. c) A step of selectively oxidizing the semiconductor substrate using the silicon nitride film and forming a thick oxide film on the portion where the silicon nitride film has been removed. d) After removing the silicon nitride film, a step of implanting impurities into the semiconductor substrate in a portion where there is no thick oxide film. A method for manufacturing a semiconductor device, comprising the steps of: e) activating and diffusing the implanted impurity by heat treatment.