JPS6235567A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To form a transistor having a thick collector layer and a transistor having a thin collector layer on the same substrate, and to form a collector wall by shallow diffusion without surrounding a base layer by forming in advance a step on a portion formed with the thick collector layer and then forming a thin collector layer. CONSTITUTION:An oxide film 2 is patterned on a portion to form a thick collector layer on a substrate 1, and silicon-etched. Then, an N-type high density diffused layer 4 is formed on the surface, an oxide film is patterned on a portion to form a thin collector layer, a separating silicon portion is removed and oxidized thereafter similarly to the conventional manufacturing method, a polysilicon 6 is laminated in a V-shaped groove 3 removed with the silicon, the back surface is polished to form a silicon island of a transistor. Here, the collector wall of a transistor having a thin collector wall is formed only on one side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device having silicon island regions having different thicknesses on the same substrate and a method for manufacturing the same.

[Conventional technology]

As is well known, high voltage transistors require a thick collector layer. Figure 2 shows I with a thick collector layer.
- FIGS. 3A and 3B are cross-sectional views showing each state in the main steps of a conventional semiconductor device including a run disk and a method for manufacturing the same. To manufacture such a semiconductor device, first, the second
As shown in Figure +a+, after patterning an oxide film (2) on an n-type (100) substrate (1), this oxide film (2)
) was used as a mask to perform anisotropic etching with an alkaline etching solution to form a V-shaped groove (3) with (111) planes on the sides.
) to form. Subsequently, as shown in FIG. 2 (bl), an n-type high-intensity diffusion layer (4) is formed on the surface of the substrate (1), and an oxide film (5) is further formed.

Next, as shown in Figure 2 (C1), polysilicon (6) is laminated to a thickness of several hundred μm on the top of the 7-shaped groove (3), and the shop board (1
The back surface of 1 is polished to expose the oxide film (5). Here, the polished surface of the substrate (1) is defined as a new substrate surface. Subsequently, as shown in FIG. 2 (dl), a base (7) and an emitter (8) are formed on the surface of this new substrate, and the substrate (
After forming each contact core by oxidizing the surface of step 1), wiring is applied to complete the desired process.

In the method for manufacturing a semiconductor device shown in FIGS. 2[al to fdl, as is clear from FIG. 2Fdl, the collector wall (9) is formed surrounding the base (7). Therefore, we used the collector all (9) as the base (7
) is shown in Figure 3.
) to td) are conventionally known.

In this manufacturing method, first, as shown in FIG.
An n-type high concentration diffusion layer (4) is formed on the surface of the type (100) substrate (I).
) and pattern the oxide film (2). next,
As shown in FIG. 3 (bl), anisotropic etching is performed using the oxide film (2) as a mask to form a 7-shaped groove (3), and then an oxide film (5) is formed.Subsequently, as shown in FIG. As shown in (C), polysilicon (6) is laminated, and the back surface of the substrate (11) is polished to expose the oxide film (5).Next, as shown in Figure 3 (dl), the polished surface is As a new board surface,
A collector wall (9) is formed only on one side of the silicon island region, a base (7) and an emitter (8) are further formed, and after each contact window is formed, wiring is provided to complete the desired process.

In the manner described above, a semiconductor device including a high voltage transistor having a thick collector layer is obtained.

[Problem that the invention seeks to solve]

Conventional semiconductor devices are configured as described above, so
If a transistor with a thick collector layer and a transistor with a thin collector layer cannot be included together, and even a transistor that does not require a high withstand voltage is formed on the same substrate as a high withstand voltage transistor, the collector layer must be 1 yen. There was a problem in that it had no choice but to become

In addition, in conventional semiconductor device manufacturing methods, when a high-voltage transistor and a transistor that does not require a high breakdown voltage are formed on the same substrate, the thickness of the collector layer is increased even for the transistor that does not require a high breakdown voltage. The thickness must be increased to match the thickness of the collector layer of the breakdown voltage transistor, which poses a problem in that the degree of integration and frequency characteristics are not improved.

In addition, when forming a collector all in a high-voltage transistor, collector all (9) may be formed on both sides of the I transistor as shown in Fig. 2 +dl, or collector all (9) may be formed on both sides of the I transistor as shown in Fig. 3 +dl. There were problems such as the transistor size increasing due to the formation of the collector all (9), such as that (9) was also diffused in the lateral direction.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a semiconductor device having a thick silicon island region 9 and a thin silicon island region.

Another invention of the present invention is a semiconductor device in which transistors having collector layers of different thicknesses are formed on the same substrate with an increased degree of integration, and at the same time, a collector layer is formed by shallow diffusion without surrounding the base layer. The purpose is to provide a manufacturing method for.

[Failure to solve the problem]

A semiconductor device according to the present invention includes a two-tier thick silicon island area on an insulating substrate, and a thin silicon island area having a thickness comparable to that of the first layer of the thick silicon island area. This is how it was done.

Further, in a method for manufacturing a semiconductor device according to another aspect of the present invention, a step is formed in advance in a portion where a thick collector layer is to be formed, and then a thin collector layer is formed by a conventional method, thereby forming a thick collector layer. A transistor having a thin collector layer and a transistor having a thin collector layer are formed on the same substrate.

[Effect]

Since the semiconductor device according to the present invention can have both a thick silicon island region and a thin silicon island region, it is possible to increase the degree of integration of an integrated circuit including a high voltage transistor and to improve frequency characteristics.

Further, in a method for manufacturing a semiconductor device according to another aspect of the present invention, prior to forming a conventional V-shaped groove, a portion other than a portion where a thick collector layer is to be formed is removed by silicon etching,
Next, a second silicon etching process is performed using the oxide film as a mask to form shallow grooves, thereby simultaneously forming a transistor with a thick collector layer and a transistor with a thin collector layer.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
Figures (δ) to +fl are cross-sectional views showing each state in the main steps of a semiconductor device and a manufacturing method thereof according to an embodiment of the present invention. The manufacturing method of this embodiment differs from the conventional manufacturing method shown in FIGS. 2(a-1) to (di) as shown in FIG. The point is that the silicon substrate +1) is selectively etched leaving a portion corresponding to the thick collector layer.

First, as shown in FIG. 1 (ta+), an oxide film (2) is buttered and silicon etched on a portion of the substrate +1j where a thick collector layer is to be formed. Next, FIG. 1 [b
As shown in Fig. 1, an n-type high concentration diffusion layer (4) is formed on the surface, and an oxide film is buttered in the area where a thin collector layer is to be formed. Step 11 (see c+) to remove the silicon part, oxidize (see Figure 1 IDl), then stack polysilicon (6) in the V-shaped groove (3) from which the silicon was removed, and polish the back surface. (FIG. 1(e)), a silicon island of a transistor is formed. Here, the collector all of a transistor having a thin collector all is formed only on one side, as shown in FIG. 3ff).

By the above manufacturing method, two types of transistors, one having a thick collector layer and the other having a thin collector layer, can be formed on the same 4-54H. Further, the collector all of the thick collector layer is also formed by drag diffusion together with the collector all of the thin collector layer, and the collector all can be formed only on one side of the collector layer. In this way, since the collector all can be formed only on one side of the collector layer by shallow diffusion, there is less lateral diffusion and less margin for element isolation, which is useful for miniaturization of semiconductor devices including high voltage transistors. .

In the above embodiment, the V-shaped groove was formed by selective etching in order to easily control the depth of silicon etching, but the groove may also be formed by normal silicon etching. 00), and silicon substrates having other orientations may also be used. Moreover, it goes without saying that the first silicon etching may be performed selectively.

In addition, although polysilicon was used as the substrate support film, the substrate support film may also be an amorphous silicon film, and as long as it does not affect subsequent processes (for example, warping or cracking due to contamination or thermal distortion), an insulating film, It may be a metal film or even an organic material film.

〔Effect of the invention〕

As described above, according to the present invention, a semiconductor device is configured to include a thick silicon island region and a thin silicon island region, so that it is possible to increase the degree of integration and improve frequency characteristics while including a high voltage transistor. There is an effect that you get what you do.

According to another aspect of the present invention, the method for manufacturing a semiconductor device is configured to include the step of first removing silicon on the semiconductor substrate, leaving only a portion of the silicon on the semiconductor substrate. Since it can be formed together with a transistor having a collector layer, and furthermore, the collector layer can be formed by shallow diffusion, it is possible to manufacture a highly integrated semiconductor device including a high breakdown voltage transistor.

[Brief explanation of the drawing]

FIGS. 1(8) to (fl) are cross-sectional views showing each state in the main steps of a semiconductor device and its manufacturing method according to an embodiment of the present invention, and FIGS. 2(a) to (fd+) show an example of a conventional semiconductor device and its Cross-sectional views showing each state in the main steps of the manufacturing method, FIGS. is an n-type (100) M plate, (2) is a double oxide film, (3) is a V-shaped groove, (4) is an n-type high concentration diffusion layer, (5)
is an oxide film, (6) is polysilicon, (7) is a base, (
8) is Emi, Yu, (9) is Collector All, (1o)
(11) is a transistor with a thin collector layer, and (11) is a 1-transistor with a thick collector layer. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A semiconductor device comprising a thick silicon island region formed in two stages on an insulating substrate, and a thin silicon island region having a thickness comparable to that of the first stage of the thick silicon island region. (2) a step of removing silicon from a region other than a desired region on a semiconductor substrate of one conductivity type; a step of forming a diffusion region of a high concentration of one conductivity type on the surface of the semiconductor substrate; a step of removing silicon in the area;
a step of forming an insulating film on the surface of the semiconductor substrate; a step of laminating a substrate support film on the semiconductor substrate; a step of polishing the back surface of the semiconductor substrate to expose the insulating film; and a step of exposing the insulating film. A method for manufacturing a semiconductor device, comprising the step of forming a high concentration diffusion layer of one conductivity type from this surface in a desired region of a silicon island, using the surface thus obtained as a new surface of the semiconductor substrate.