JPS604236A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable reduction of a bird's beak in size and to facilitate minituarization of the MOS semiconductor device by forming a substance consisting of Si oxide mainly only in a region except element forming regions. CONSTITUTION:A masking substance 22 is formed on a first conductive type Si substrate 21 followed by photo-etching to selectively leave the masking substance 22 only in element forming regions 22a-22c. After the element isolation regions 23a and 23b are etched to the predetermined depth to remove the masking substances 22a-22c, solution consisting of Si compound mainly is spread followed by heat treatment. Consequently, the solution consisting of Si compound mainly changes into substances 24c and 24d consisting of Si oxide mainly to become a stable solid substances. After that, a gate electrode 27 and source and drain regions 28a and 28b are formed. Thus, accuracy in formation of the element isolation region is almost determined by accuracy in etching of the Si substrate 21. If etching of high anisotropy is used, formation in the region to be determined based on the masking substance becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and particularly enables high-density integration. 11.1 is a method for manufacturing a semiconductor device that facilitates manufacturing an MO8 type semiconductor device with a small gate width with good stacking capacity.

As the MO8O8 type semiconductor device becomes more popular, the manufacturing constraints are such that it has to be made with high accuracy within a predetermined dimension.

make it difficult to manufacture. The reason is shown in Figures 1 and 2.
This will be explained using figures. FIG. 1 shows a planar structure of an N1O8 type semiconductor device. This figure shows a source region 1 in the active region of a silicon substrate 6. It is shown that a drain region 2° is provided and a gate is provided through a gate insulating film.The width of the gate electrode is shown as 5, and the gate length is shown as 4.

FIGS. 2(a) to 2(g) are cross-sectional views of a method for manufacturing the MO8 type semiconductor device shown in FIG. 1, showing the steps in the order of steps based on the conventional method.

Figure 2 (f) shows the structure of the 11 Noah plane shown at A-A' in Figure 1, and Figure 2 (g) shows the structure of the cross section shown at B-B' in Figure 1. show.

As shown in FIG. 2(a), a silicon oxide film 15 is formed on the main surface of an i-type single crystal silicon substrate 11 (hereinafter abbreviated as silicon substrate 11), and then, for example, For high temperature thermal oxidation of silicon substrates such as silicon nitride, 711 oxidizing material *16 is deposited. Furthermore, a photoresist 12 is then formed.

Then %E'! As shown in FIG. 42 (bl), using a known photoetching technique, the photoresist 12 is left only at a predetermined location of the silicon nitride film 16 on the silicon oxide film 15 on the silicon substrate 11, and the other parts are etched. Remove the photoresist in place 12 each
a, 12b, and 12c.

Next, as shown in FIG. 2C, using the photoresists 12a, 12b, and 12c as masks, a known etching method is performed to leave the bIJ silicon nitride film 16 only at predetermined locations, and etching the silicon nitride film 16a, 16b, and 16c, respectively. and remove the others.

After that, the photoresist 12a, 12b.

After removing the silicon nitride films 16a, 16b, the entire device is exposed to a high temperature oxidizing atmosphere.
The silicon substrate 11 except for the area covered by 16c
The front surface 1 is covered with a thick [3] silicon film. When expressed in Hzl, it becomes as shown in 5ts2 figure (d), where 143 and 14b correspond to the thick silicon oxide substrate, respectively.

Furthermore, as shown in FIG. 2(e), the silicon nitride films 16a, 16b, and 16c are removed. That is, the regions 13a and 13b where the thick 1β silicon films 14a and 14b shown in FIG. The area sandwiched between these two areas is the element area.

Next, as shown in Figure 2), a gate electrode 17 is formed at a predetermined location on the top of the element by using a known photoetching technique.

Then, for example, using ion implantation method or thermal diffusion method, 1
Surface of the silicon substrate 11 ``top j'') [An impurity diffusion layer that will become a source train region at a predetermined location.

Form 18a and 18b in FIG.
Obtain the basic structure of an OS type semiconductor device.

After that, lead electrodes are formed from the source/drain regions and the gate electrode, respectively.

An MO8 type semiconductor device is obtained.

The method of manufacturing an MO8 type semiconductor device as described above encounters a serious limit when attempting to miniaturize the device, that is, to manufacture a device with a small gate length and gate width. It is the silicon nitride j shown in Fig. 2 td).
Using 16a, 16b, and 16c as masks, one-liquid silicon IJf with separation between eggplants is placed around the element formation area.
When forming i14a and 14b, the silicon oxide film forms the silicon nitride film 1 for the mask, which is called a bird's beak.
A kind of digging phenomenon occurs from the periphery of 6a, 16b, and 16C toward the inside of the element formation area, and the element formation area becomes smaller than a predetermined thickness.

In FIG. 3 ta+, 31 indicates the designed size of the element formation region on the photomask, and 11 is the designed value. At that time, if the size of the element formation region after forming the silicon oxide film 34 using the silicon nitride film 32 as a mask is t2, then the size of the bird's beak is △
If t, Δt is given by the following formula.

Δt is −(jt/−2)/2. Specifically, the size of Δt is approximately Δt˜0.8 μm when the silicon oxide film 34 is 1 μm and 8 degrees. When t□ is sufficiently large, △t is not a problem, but when tl becomes about 1 to 2 μm, the size of △t occupies a relatively large proportion, and there is almost no area for forming the element. The present invention aims to prevent such bird's beak △
It is possible to make t very small, thereby reducing M.O.
The present invention provides a manufacturing method that facilitates miniaturization of an 8-type semiconductor device.

In other words, the present invention is characterized by: - selectively forming a substance that can serve as a mask during etching of the silicon substrate only on regions where elements are to be formed on a conductive single crystal silicon substrate (hereinafter abbreviated as silicon substrate); The device is etched by etching a region on the silicon substrate excluding the region where the device is to be formed to a predetermined depth using a substance that can serve as a mask, and by applying and baking a solution containing a silicon compound as a main component. This method attempts to form an inter-element isolation insulating region by forming a substance containing silicon oxide as a main component only in regions other than the region to be formed.

Figures 4(a) to 4(f) are based on the present invention. An example will be shown in the order of its manufacturing steps.

As shown in FIG. 4(a), a front 812
A material 22 that can serve as a mask (hereinafter abbreviated as mask material) is formed when etching the silicon substrate 21. This masking material may be, for example, a material such as a photoresist in known photoetching techniques. Of course, materials other than photoresist may also be used as long as they have properties that are effective as a mask when etching the silicon substrate 21, as described above.

Next, by using a known photoetching technique, the mask material 22 is selectively left only in the region where the element is to be formed, and is removed from the other regions. FIG. 4 (bl indicates such a state; in FIG. 1, 22a, 22b, 22c indicate mask materials selectively left on the area where the element is to be formed; 23a;
, 23b6 indicate element isolation regions.

Next, as shown in FIG. 4 (C1), the mask material 22
Using a, 22 b, and 22 c as masks, the element amount h·1 on the surface of the silicon substrate 21 [area 23 a.

He has a talent for etching 23b to a predetermined depth.

Thereafter, using the mask objects J22a, 22b, and 22c as masks, impurities having the same conductivity as that of the substrate are implanted into the element isolation region 2, for example, by ion implantation.
3a and 23b to form a channel stopper region.

Thereafter, as shown in FIG. 4(d), the mask material 2 is
After removing 2 a, 22 b, and 22 c, we get 1.

Apply a solution based on silicone compounds, such as an ethanol bath of silanol. At that time, selective etching was performed as described above. Inter-element isolation region 23 a
, 23b, the solution containing the silicon compound as the main component remains. (shown in Figure 4 243.24b).

Thereafter, by performing a heat treatment step (especially called calcination), the solution containing the silicon compound as the main component is converted into substances 24c and 24dKi containing silicon oxide as the main component,
Turns into a stable solid substance.

- As shown in Figure 5 (ta) of the man's hand, as shown in Figure 4 (d), [)IJ element interval 1'f! L'jJt area 23
a, 23b as well as *l]iJ element region (5)
1A(a) 52a, 52b, 52c) may also be coated with a solution containing the silicon compound as a main component.

In that case, as shown in FIG. 5(b), after the subsequent heat treatment step, the element regions 52(a), 52(1)l,
The substance 55 whose main component is silicon oxide remaining on 52+C1 is in the 1'iK'pR region 53 a, 5 by the amount of the element.
3 b, 53 c and the element formation region 52 (a
), 52(bl, 52(C), so by utilizing the difference, for example, an anisotropic etching method is used to form the inter-element isolation regions 53(al, 53(C)).
The above-mentioned acid can be formed only in b) (Fig. 5(C)).

After that, as shown in Figure 4(f), the gate 11f is applied to the area where the element is to be formed.
(k27 and source/drain regions 28a, 28bf
: Formed to obtain a basic structure of MO8'B1 semiconductor device 11.

Thus, based on the method taught by the present invention.

As shown in FIG. 4(C), the accuracy of forming the element isolation region is mostly determined by the degree of etching coverage of the silicon substrate 21. !l) Etching (e.g.
When using the reactive ion etching method (reactive ion etching method), it is possible to form the separation region between the resistors in the region determined by the mask material, and the element formation region 17F can also be formed in accordance with the pre-designed pattern. can be manufactured in mind. In other words, the amount of elements, which was called a bird's beak in IFI, is 1.
There is no digging into the element formation area in one area.
It is possible to form a highly accurate element formation region suitable for high integration.

FIG. 1 is a plan view showing the planar structure of a typical MO8 type semiconductor device, FIG. )
, (b) are schematic diagrams showing the situation of bird's beak, and FIGS.
5 is a cross-sectional view showing the method for manufacturing a type semiconductor device in the order of steps.
Figures (a) to (C) are respectively process order 1 of other embodiments of the present invention.
This is an analytical surface diagram.

In addition, in Figure 1, 11, 21.35...
female single crystal silicon substrate, 12.22... photoresist, 16... oxidation-resistant film, 14 a,
14 b, 14 c, 14 d... Single liquefied silicon film for inter-element distribution, 24 c, 24 d, 55...
Substances mainly composed of silicon oxide, 13a, 13b, 2
3a, 23b=--element isolation region, 17.27...
...Gate electrode, 18a, 18b, 28a, 28b.
. . . Source/drain regions.

￥21￥Il 2nd time −□− " 1 police officer 4 pieces Jz2 What happened to Mine? ha otsu sy-a

Claims (1)

[Claims] A step of selectively forming a material that can serve as a mask during etching of the -6K type single crystal silicon substrate on a region where an element is to be formed on a single conductivity type single crystal silicon substrate, and using the material that can serve as a mask as a mask, A step of etching a region on a conductive single crystal silicon substrate excluding the region where the element is to be formed to a predetermined depth, and a step of etching a region W excluding the region where the element is to be formed by coating and baking a solution containing a silicon compound as a main component. 1. A method for manufacturing a semiconductor device, comprising: forming a substance containing silicon oxide as a main component.