JPH01107552A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To form an element isolating region without considering a conversion difference and to highly integrate a semiconductor element by supplying oxygen ions to a section to be as the element isolating region of a single-crystal substrate for forming a semiconductor device. CONSTITUTION:Oxygen ions are supplied to a section 35a to be formed as the element isolating region of a single-crystal substrate 31 for forming a semiconductor device, thereby converting the region into polycrystalline and/or amorphous state. Then, an element forming region 45 (active region) and an element isolating region 43 are respectively fored by selective growth. A region 37 to be converted into polycrystalline or amorphous state can be accurately specified, for example, as the size of a resist pattern. Thus, the element isolating region and the active region are formed without conversion difference, thereby highly integrating a semiconductor element.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for manufacturing a semiconductor device characterized by a method for forming a region M corresponding to the amount of elements of the semiconductor device. It is something.

(Prior Art) In semiconductor devices such as ICs and LSIs, it is necessary to electrically isolate each element formed on a substrate from each other, and for this reason, element isolation technology is provided between each element on the substrate. There is. In order to improve the degree of integration of semiconductor devices,
In addition to reducing the size of the device, it is also important to reduce the area of the device isolation region.

One of the conventionally known element isolation technologies is Shi0(:
There is something called O3 (a technology from Philips).

This technique will be briefly explained below with reference to FIGS. 2(A) to 2(G). Note that FIGS. 2(A) to 2(G) are process diagrams for forming an O3 element in LO, and show the state of the semiconductor device at each main step in the process. This is a schematic diagram using a cross-sectional view focusing on one element portion.

First, a thermal oxide film 13 with a thickness of, for example, 360 mm is formed on a single crystal silicon substrate 11 by a conventional method (FIG. 2(A)).Next, on this thermal oxide film 13, A nitride film indicated by 15 is grown by low pressure CVD method (second
(B)), next, 17
A resist film is formed as shown in FIG. 2(C)), and then the resist film 17 is used as a mask and the exposed portions of the nitride film 15 and the thermal oxide film 13 are removed using an anisotropic plasma etching method. , a part of the substrate 11 is exposed (FIG. 2(D)).

Next, the resist film 17 is removed using a suitable chemical to expose the surface of the remaining portion 15a of the nitride film (see FIG.
).

Next, the remaining portion 15a of this nitride film @as a mask,
A thermal oxidation process is performed on the exposed portion of the substrate 11 to form a field oxide film 19. In this thermal oxidation process, a part of the field oxide film 19 enters from around the nitride film remaining part 15a to the lower side of the nitride film remaining part 15a, creating a so-called bird's beak (Bird's beak).
d's beak) is formed (FIG. 2(F)).

Next, during the formation of the field oxide film, the remaining portion 15 of the nitride film is
The thin oxide film indicated by +5b formed on the substrate a is removed using dilute hydrofluoric acid, and the remaining portion of the nitride film 15a is removed by placing it in phosphoric acid heated to a temperature of about 170°C. The substrate is immersed in dilute hydrofluoric acid for a time long enough to remove the oxide film under the remaining portion 15a of the nitride film, thereby exposing the region 21 of the substrate 11 corresponding to the active region. By such a method, the active region 21 is obtained, in other words, an element isolation region is formed around this active region.

(Problems to be Solved by the Invention) However, in the conventional manufacturing method described above, a portion of the field oxide film 19 enters from around the remaining portion 15a of the nitride film to the underside of the remaining portion 15a of the nitride film. However, there was a problem in that this portion narrowed the active region. That is, the width of the completed active region is somewhat narrower than the original width of the resist film 17. This narrowing dimension value is the sum of the intrusion of the nitride film under both sides of the remaining portion 15a (the portions marked b1 and b2 in Fig. 2 CG), and is generally about 0.7 um. be. Therefore, the difference between the resist pattern dimension and the completed dimension of the active region (or conversely, the element isolation region) (this will be referred to as a conversion difference) is approximately 0.7 um using the conventional method. .

Due to this difference in conversion, it is necessary to prepare the dimensions of the resist film with an allowance in advance for this difference in conversion, and the cell area on the resist pattern becomes large. This becomes a problem when converting.

This invention was made in view of these points,
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a semiconductor device, which enables the formation of element isolation regions without considering conversion differences, thereby achieving higher integration of semiconductor elements.

(Means for solving the problem) In order to achieve this object, according to the method for manufacturing a semiconductor device of the present invention, oxygen ions are supplied to a region where an element isolation region is to be formed in a single crystal substrate for forming a semiconductor device. and epitaxially growing a semiconductor layer on the single crystal substrate to which oxygen ions have been supplied.

In carrying out the present invention, it is preferable that the aforementioned oxygen ions be supplied by oxygen ion implantation or oxygen ion beam irradiation.

Further, in carrying out the present invention, it is preferable that the aforementioned single crystal substrate be a single crystal silicon substrate.

(Function) According to the method for manufacturing a semiconductor device of the present invention, by supplying oxygen ions to a portion of a single crystal substrate for forming a semiconductor device that is desired to be an element isolation region, this region becomes polycrystalline and/or amorphous. We aim to When a semiconductor layer is epitaxially grown on a single crystal substrate including such a polycrystalline or amorphous portion, the semiconductor layer will not grow on the polycrystalline or amorphous portion. Taking advantage of this fact that the active region is not formed, the device formation region (active region) and the device isolation region are separated.

(Embodiment) An embodiment of the method for manufacturing a semiconductor device of the present invention will be described below with reference to FIGS. 1(A) to 1(H). Furthermore, the first
Figures (A) to (H) are process diagrams for forming an element isolation region according to an example, and show how the element isolation region is formed in each main step in the process, focusing on one element part of a semiconductor device. This is shown using a cross-sectional view. However, it is understood that these drawings are only schematic representations to the extent that the present invention can be understood, and therefore, the dimensions, shapes, and arrangement relationships of each component are not limited to these drawings. Furthermore, it should be understood that the numerical conditions, chemicals used, equipment used, etc. in the following description are merely illustrative, and the present invention is not limited only to these conditions.

First, a single crystal substrate for forming a semiconductor device is prepared. In this embodiment, the single crystal substrate for forming a semiconductor device is a single crystal silicon substrate, which corresponds to the one indicated by 31 in FIG. Note that the silicon substrate in this case also includes a substrate on which a single crystal silicon layer is epitaxially grown.

On this silicon substrate 31, a thermal oxide film indicated by 33 is formed to a thickness of, for example, 250 to 600 layers (FIG. 1(A)).
.

Next, in order to form on the silicon substrate 31 an active region for forming semiconductor elements such as transistors and a region for electrically isolating these elements, the following steps are taken in this embodiment.

First, a resist pattern 35 is formed on the substrate 31 (FIG. 1(B)). In this example, a positive resist is used, and the film thickness is 8000 to 100.
00 people. Here, the resist film 35 of the substrate 31
The portion covered by the resist film 35 corresponds to the active region formation region, and the portion not covered with the resist film 35 corresponds to the region 35a in the element isolation region formation region (FIG. 1 CB).
It will be equivalent to .

Next, oxygen ions (indicated by P in FIG. 1C) are supplied to the region 35a where the element isolation region is to be formed.

In this embodiment, oxygen ion implantation is used.

The ion implantation conditions are an acceleration voltage of 30 KeV and an ion concentration of 3 x l Q I 3 ions/cm2.
Thermal oxide film 33I! Do it by typing through,
By this supply of oxygen ions, the portion of the substrate 31 in the intended element isolation region 35a is brought into a polycrystalline or amorphous state, that is, S
It will be as shown by iOx (area indicated by 37 in the figure)
. The resist film 35 is removed using a suitable chemical, such as a mixture of sulfuric acid and hydrogen peroxide (FIG. 1(D)).

Next, the thermal oxide film 33 is removed using dilute hydrofluoric acid to expose the surface of the substrate 31 including the portion to which oxygen ions have been supplied (FIG. 1(E)).

Next, a semiconductor layer that will become an active region, such as an N0-type silicon epitaxial layer, is epitaxially grown on the substrate 31 including the portion to which oxygen ions have been supplied.

Possible methods for this epitaxial growth include CVD, molecular beam epitaxy, or liquid phase epitaxial method, but in the case of this embodiment, for example, the literature (Monthly Semiconductor World).

December 1986 issue, PP, 62-67 r-optical CVO
The silicon layer is epitaxially grown using the method disclosed in ``Low Temperature Si Ehi'; Specifically, the raw material gas is 5i2He,
5jH2F2/H2, and the light source used is low pressure H9,
The semiconductor layer was grown under conditions where the main growth temperature was about 200°C.

In the epitaxial growth process, the region into which oxygen ions are implanted, that is, the region intended for element isolation region, has lost its single crystal state, and recrystallization in this region does not occur due to low-temperature growth, so the semiconductor The layer does not grow on this area, but only on the area that will become the active area. Taking advantage of this property, a silicone epitaxial layer 39 doped with phosphine, for example, is grown to a thickness of, for example, about 3 μm only in the region that will become the active region of the substrate 31 (FIG. 1(F)).

Next, using, for example, a low pressure CVD method, 41
An insulating layer shown by, for example, a SiO□ film is grown to a thickness of 5 to 6 um (FIG. 1(G)').

Next, by anisotropic plasma etching using, for example, a fluorocarbon gas, SiO□1141! While planarizing, the silicon epitaxial layer 39 is removed until it is exposed.

According to the method described above, the element isolation region indicated by 43;
5 can be formed together with the active region without any difference in conversion (FIG. 1(H)').

In the above-described embodiment, oxygen ions are supplied to the region where the element jIl region of the single crystal substrate for forming a semiconductor device is to be formed, using an ion implantation technique. This is to utilize the ion implantation equipment used in semiconductor device manufacturing lines; however, the method of supplying oxygen ions is not limited to this, and other methods may of course be used. Another possible method is, for example, a method using oxygen ion beam irradiation. Note that in the case of the method using oxygen ion beam irradiation, if the beam is controlled with high precision, it is not necessary to use resist Si.

Furthermore, in the above embodiments, the single crystal substrate is a silicon single crystal substrate, but the single crystal substrate is for forming a semiconductor device and is made polycrystalline or amorphous by oxygen ions. It is clear that the present invention can be applied to the formation of element isolation regions in the manufacturing process of semiconductor devices using single crystal substrates.

(Effects of the Invention) As is clear from the above description, according to the method for manufacturing a semiconductor device of the present invention, by supplying oxygen ions to a portion of a single crystal substrate for forming a semiconductor device that is desired to be an element isolation region, This region is made polycrystalline and/or amorphous, and then selectively grown to form an element forming region (active
(area) and an element isolation region are respectively formed. This region to be made polycrystalline and/or amorphous can be precisely defined according to the dimensions of the resist pattern, for example, so that element isolation regions and active regions can be formed without conversion differences. Ru.

Therefore, it is possible to provide a method for manufacturing a semiconductor device that allows highly integrated semiconductor elements.

[Brief explanation of the drawing]

FIGS. 1(A) to (H) are manufacturing process diagrams for explaining the method for manufacturing a semiconductor device according to an embodiment of the present invention, and FIGS. 2(A) to (G) are diagrams of a conventional manufacturing method for a semiconductor device. It is a manufacturing process diagram provided for explanation. 31...Single crystal substrate for semiconductor device formation 33...Thermal oxide film, 35-...Resist pattern 35a...
Element isolation region formation planned region 37... Polycrystalline and/or amorphous region 39... Semiconductor layer (epitaxial growth layer) 41... Insulating layer (SiO2 layer) 43... Element isolation region, 45 -...Active region. 31. Single crystal substrate 33 for forming a semiconductor device, thermal oxide film 35; resist pattern 35a/element valve MM region formation planned region 37: polycrystalline and/or amorphous region Diagram for explaining the manufacturing method of the present invention Figure 1 Provides an explanation of the manufacturing method of the present invention Factor 45: Active II region Figure 1 Provides an explanation of the manufacturing method of the present invention Figure 2, t5a /3 & 7/ Figure 2

Claims (4)

[Claims] (1) A method comprising the steps of supplying oxygen ions to a region where an element isolation region is to be formed in a single crystal substrate for forming a semiconductor device, and epitaxially growing a semiconductor layer on the single crystal substrate to which oxygen ions have been supplied. A method for manufacturing a semiconductor device. (2) The method for manufacturing a semiconductor device according to claim 1, wherein the oxygen ions are supplied by oxygen ion implantation. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the oxygen ions are supplied by oxygen ion beam irradiation. (4) The method of manufacturing a semiconductor device according to claim 1, wherein the single crystal substrate is a single crystal silicon substrate.