JPS5827341A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To improve the characteristics of a semiconductor device by removing an Si3N4 film on an interelement isolating zone region with a thermal H3PO4 without roughing the surface of a lower Si substrate. CONSTITUTION:A dioxidized silicon film 22, an antioxidative film 23 and a dioxidized silicon film 24 of the prescribed pattern are respectively laminated on an interelement isolating zone forming region C and an element forming region A on a semiconductor substrate 21. Then, a photoresist film 25 is formed, a window is opened at the film 25 on the region C, and with the film as a mask the film 24 on the region C is removed. Then, nitrided silicon films 23 on the regions C and A as masks the first field oxidation 26 is performed. Then, a photoresist film 27 opened with a window only on the region C is formed, and with the film as a mask the film 23 on the region C is removed, and an isolating band forming impurity is introduced to the region C. Thereafter, the second field oxidized film 28 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor device, and particularly to an improvement in a method for manufacturing a Paibov semiconductor device O.

In order to reduce the base-collector junction capacitance of the Rupaipov transistor and improve the switching characteristics of the Totsun V-star, a semiconductor device having a mourning structure in which the base region Oa8 is surrounded by thick silicon dioxide (S:LOj) has been conventionally provided. There is.

Figure 1 shows a cross-sectional view of a semiconductor device with such a structure.
In the figure, l is a PWIO61 substrate, 2 is an N-type salt layer, 8 is a nine-layer separator layer into which P-type impurities are introduced, 4 is an N-type 81-layer pitaxeum layer, 6 is an expanded feed μ-doped oxide film, 6 is the base area of Pg, 7 is N! The emitter region of l is shown.

Conventionally, this kind of semiconductor device is I! The steps shown in Figure 1g2 and up to JI811il are taken.

That is, first, as shown in Figure j1g2, a vapor phase growth method (CVD method) is applied to the 81 substrate 1 on which the buried layer 2 described above is formed.
Or thermal oxidation method 5iOsllllll to 1000A
C) Thickness is formed, and then multi-windowed silicon is formed by CVD method (
Si3N4)llll12 is formed to a thickness of 1 sooAo. After that, using a photolithography method, the above-mentioned Sin, I
ll 11 and Si, at least S of the N4 film 12
i. The N4 film 12 is formed into a predetermined pattern.

70gIL As shown in Figure 8, Si, N4. Lufield oxidation 11418 by thermal oxidation method using $112 as a mask
is formed to a thickness of approximately 4oooAo.

The wk314 pattern as shown in the figure)
5i1N4 on the region where the isolation zone is to be formed using the 7 Otorerest film as a mask.
77412 @Remove by plasma etching method.

Thereafter, as shown in the 5th WA, using the photoresist group 14 as a mask, borium * (B") ions are applied to J15 KeV5X.
Ion implantation is performed under the condition of 10''C to form an isolation band region between elements.

Photoresist 11111 as shown in Figure 6
After removing 4, a field oxide film 15 of JI2 is formed thickly to a thickness of 700 OA on the violet isolation II region C. When formed, the thick shell is approximately 52oof thick.

Thereafter, the substrate is heat-treated to activate the ion-implanted regions and form isolation band regions 16 between elements.

Next, as shown in FIG. 7, the substrate was heated with hot phosphoric acid (Hgpo4
) to remove 51sN4Ill 2 A on the element formation region (on the base region) shown in Figure 116, and then form a 51o1 film 17 to a thickness of about 100OA on the exposed base region by thermal oxidation. .

1118, then:y#) and N7. )311
Using 18 as a mask, phosphorus atoms (B+) are ion-implanted, and then cis) 1118 is removed and heat treated to form the pace region 6 shown in FIG. 1, described above. I'll see you later (
A transistor was formed by ion-implanting OIJ type impurity atoms such as arsenic (A8) to form the emitter region 7 described above.

However, in this better method, the photoresist film 14 is opened as shown in the process of FIG.
When removing the layer 4, the underlying SiO and Jllll may be etched and the underlying 81-layer bitaxy μ layer 4 may be exposed. Once the S1 is exposed, the S1 is etched more rapidly than the 5-inch film or SilN4g, and the surface of the S1 becomes rough or grooves are formed. This causes defects such as unevenness in some parts.

On the other hand, in order to remove 811N41112 with heat a and po4 etching solution, it is necessary to remove the 5ilN4 film 12 in other areas.
There is a drawback that some kind of protective film is required to leave A, and the multiple steps are complicated.

The present invention eliminates the above-mentioned drawbacks, and provides thermal aapo4 to connect the 5j-IN4 Ill 2 on the inter-separation zone area to the lower S
The purpose is to obtain a semiconductor device with good characteristics by removing it without disturbing the surface of the substrate. A method for manufacturing a semiconductor device to achieve this purpose is to form an isolation zone between elements on a semiconductor substrate. A step of laminating a silicon dioxide film, an oxidation-resistant film, and a silicon dioxide group in a predetermined pattern on the planned area and the area where the element is to be formed, and after forming a photoresist on the substrate, on the area where the isolation zone between the elements is to be formed. A step of removing the silicon dioxide group on the region where the element amount j111 is to be formed using the nine photoresist groups as a mask. The step of performing field oxidation on the field oxidation shown in Fig. fs1 using the silicon nitride film on the S-band formation area of the ilI element as a mask and on the element formation area as a mask. ) A step of forming a film, using the photoresist group as a mask to form a Jll band between the elements yt! A step of removing the vulcanized V recon film on the area, a step of introducing an impurity for forming an isolation band into the area where the isolation band is to be formed, and then a second field oxidation is performed on the formed isolation band area. This method is characterized by including a step of forming a thick silicon dioxide film.

The features of the present invention will be explained in detail below with reference to the drawings.

Figures 9 through 18 are cross-sectional views showing the steps of an embodiment of the method for manufacturing a semiconductor device of the present invention. First, as shown in Figure N9, an 81 substrate (V recon epitaxial μ layer) 21
A predetermined pattern of Sing II 22 is placed on the element formation area A and the element isolation zone formation area C.
oL sl, N4II! s t6ooJ, 5101 membrane 2
4 is laminated into a three-layer structure with a thickness of xooo, M. In this way Sj-0gm122, Si, N41112
g, 510zl1424 in a predetermined pattern in a three-layer structure, S10! Exhibition 22.511N
411128. After successive growth of 810 g film with 24 t CVDl, 7 photoresist films are brittle on the plate substrate.

After that, the photoresist film is formed into a predetermined pattern by the 7 otolithography method, and the lower SLOg is exposed using the patterned photoresist as a mask.
N4 film, SlogMf: Etched into a predetermined pattern by plasma etching method.

After that, as shown in the JIIO diagram, after spreading a resist film on the station board, the area C where the inter-chord isolation zone is to be formed is dulled, and the inter-element isolation zone is formed using hydrofluoric acid (HF) or the like. After etching and removing the uppermost 8102 film 24 in the formation area CJ:, the photoresist 1125 is also removed using a resist removal solution.

Thereafter, as shown in Fig. 1811, the three-layer structure of 810xlt22, Si, N4M2B formed on the area C where the isolation zone is to be formed, and the 510gN22.81slL4m2B and 8102 film 24 formed on the area A where the element formation is planned are masked. As a first layer, a field oxide film 26 is formed.

After that, the field oxide film 26 and device formation plan G4 Plant A
Sis N4I14 on the element amount*band formation area C using the heat EsPQ4 using the 510g layer 24 above as a mask.
After etching 2B, the underlying 510g11122 is also etched and removed using HB' to expose the surface of the S1 substrate.

In this way, the field oxidation 1126 and the 5inz film 24 on the area where the element is to be formed will act as a mask, and this part will not be attacked by the heat HaPO4, so only the Si and N4 films 28 on the area where the isolation zone will be formed will be in the designated area. It can be etched and removed with a width of .

After that, using HF etc., the 8inz film 22 under the 5iaN4 film is
Also etched. In this way, calculations can be made without damaging the surface of the 811 & plate surface in the region where the isolation band is to be formed.

Thereafter, as shown in FIG. 12, a photoresist 1127 is formed on the substrate using a photolithographic technique with a window opening only on the isolation zone area, and a mark (B+) is placed on the exposed area where the isolation zone is to be formed. 80 ions like the arrow
Ion implantation is carried out at a dose of KeV of 5×10"67 cm".

As shown in the Wk$18 figure, the second field oxidation
428 is formed to a thickness of about yooof on the ion-implanted region where the isolation band is to be formed and on the region subjected to the first field oxidation.

At this time, there is a second field oxidized area on the first field oxidized area.
This means that a field oxide film with a thickness of 82 GOA is formed, including the dimensions of the first field oxidation. ◎ Then, 5101M22.5j-s on the area where the element is to be formed.
N41128, Sing g also HF and heat H
, PO4 and then selectively implanting boron ions to form a space region in the element formation region as shown in FIG. 1.

As described above, according to the method of the present invention, the substrate surface of the inter-element isolation zone O81 is not etched abnormally, so there is no need to form grooves or steps in this area. This brings about the advantage that a highly reliable semiconductor device can be obtained at a high yield.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a Bybov type semiconductor device, FIGS. 2 to 8 are sectional views showing the steps of a conventional semiconductor device manufacturing method, and FIGS. FIG. 3 is a cross-sectional view of a process showing an example of a method for fabricating a device. In the figure, 1 is the S1 substrate, 2 is the digging layer, Li2゜29
4, 21 are N-type epitaxial μ layers,
5 is a field oxide film, and 6 is a base region. 7 is the emitter area, 11.17.22.24 is S10g
Membrane, 12.12A, 2B is Sj-sN4M, 18.26
is the first field isthmus film, 14.1&, 25.27 is the near t) L/N space, 15.28 is the second field isthmus film, A is the area where the element is to be formed, and C is the area between the elements. In the region where the separation zone is to be formed, B+ indicates boron ions. Figure 1 Figure 2 Figure 1 Li Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] a step of laminating a silicon dioxide film, an oxidation-resistant film, and a silicon dioxide group in a predetermined pattern on a region where an isolation band is to be formed and a region where an element is to be formed on a semiconductor substrate;
After forming the photoresist film on the substrate, opening the photoresist layer on the region where the isolation zone is to be formed;
1. Using the open photoresist group as a mask, removing the silicon dioxide group on the region where the isolation band is to be formed;
A step of performing 11111th feed μ oxidation using the electrified silicon group on the area where the isolation band is to be formed and the area where the element is to be formed as a mask, and forming a photoresist film only in the area where the isolation band is to be formed. a step of using the photoresist film as a mask to remove the electrified F silicon film on the region where the isolation zone between the elements is to be formed, a step of introducing a predetermined material for forming the separation zone into the region where the wrinkled element isolation zone is to be formed; Confectionery batch JI formed by ls2 feed μ oxidation
Manufacturing method 0 of a semiconductor device characterized by including a step of forming a thick silicon dioxide group on an IIF region