JPS6214444A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To increase resistance to moisture and to improve flatness by a method wherein a coating of boron-phosphorus silicate glass (BPSG) or of the same including some germanium is formed on an insulating film and the coating is caused to melt for the production of a flattened surface. CONSTITUTION:On a polycrystalline silicon wiring 2 provided on a semiconductor substrate 1, a coating is provided by CVD of a 5,000Angstrom -thick PSG film 3. A BPSG film 5 approximately of the same thickness is laid on the PSG film 3. The BPSG film 5 is heated to melt for the flattening of the surface. Annealing in a high-humidity oxygen atmosphere by means of a carbon dioxide gas laser or a lamp suits the purpose. By using this method, the BPSG film 5 may be caused to melt with the PSG film 3 remaining not melted, which contributes to the flattening of the surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of forming an insulating film.

Semiconductor devices such as ICs are highly integrated, such as LSI and VLSI, because the smaller and more highly integrated they are, the more they have the advantage of improving performance such as high-speed operation.

On the other hand, if ICs become WXm and highly integrated, the wiring to connect minute elements on the top surface becomes complicated, resulting in two-layer, three-layer
Wiring has come to be formed in multiple layers.

Such multilayer wiring is formed through an insulating film between the eyebrows, but since the wiring is formed on a surface with severe steps,
Wiring becomes easily disconnected or short-circuited. Therefore, it is desired to make the surface of the glabellar insulating film as flat as possible.

[Prior art and problems to be solved by the invention] Conventionally, various methods have been used to flatten the surface.
They have drawbacks such as complicated processes, and
In many cases, the surface is not sufficiently flattened. Among these, the planarization method that is considered to be the simplest and easiest to form is a method of applying a solution to the surface and baking it to fix it. FIG. 2 shows a structural cross-sectional view of an example of this method.

In FIG. 2, 1 is a semiconductor substrate, 2 is a wiring made of polycrystalline silicon, 3 is a phosphorous silicate glass (PSG) film,
4 is a spin-on glass crotch.

The outline of this formation method is that chemical vapor deposition (C
A PSG film is deposited by VD) method, and a spin-on glass solution is applied thereon. Then, the surface becomes flat, and then heat treatment is performed at a temperature of about 400° C. to fix the solution.

This spin on glass
is a silicon compound melted in an organic solvent, which is treated at low temperatures to evaporate the solvent and form silicon oxide (Si02).
N! Let i remain. This remaining film has good insulation properties, so
It can serve as a flattening insulating film between the eyebrows.

In addition to spin-on glass, there is also something called PLO3, which is also based on organic resin and has similar properties, so it is used for flattening between wiring layers like spin-on glass.

As described above, the method of applying a solution is easy to form and has excellent flatness. However, it has been found that the insulating film does not have sufficient moisture resistance because the organic resin remains in the film, and also contains other impurities, which may have an adverse effect on the IC.

The present invention proposes a forming method that is free from such concerns, is easy to form, and has excellent flatness.

[Means for solving the problem] The problem is that boron phosphorus silicate glass (BP) is used on the insulating film.
SG) or boron phosphorus silicate glass containing germanium (GeB PSG),
Alternatively, the problem can be solved by a semiconductor device manufacturing method that includes a step of melting GeBPSG to flatten the surface.

[Operation] That is, in the present invention, BPSG or GeBPSG, which has a lower melting point than the PSG film, is grown in a vapor phase on the psc film, and is melted and planarized.

Then, a flat surface is formed with these insulating films having good moisture resistance.

[Example] Hereinafter, embodiments will be described in detail with reference to the drawings.

FIGS. 1(a) to 1(C) show sequential cross-sectional views of the formation process according to the present invention. First, as shown in FIG. In, CVD
Deposit SGIJi3 to a film thickness of approximately 5,000 or more using a method. Next, as shown in FIG. 2B, a BPSG film 5 of approximately the same thickness is deposited thereon. PSG film 3. Bp
Since both sclff5 are deposited by CVD method, the same -CV
Can continue to grow in the D apparatus.

Next, as shown in FIG. 1 (TC), a BPSG film 5 is added. ! Melt and flatten the surface. For this purpose, carbon dioxide laser annealing or lamp annealing in high humidity oxygen is suitable. This allows the BPSGIll 15 to be melted and the surface to be flattened without melting the PSG film 3.

Note that the BPSG film contains phosphorus (P) in 5i02.

It is a material containing about 4% by weight of boron (B), and the melting point of PSGll is about 1050 ° C.
The melting point of the BPSG film is about 950°C. Therefore, in the above example, only the BPSG film can be melted.

Also, B P S G11l! Instead of GeBPS
A G film may be grown and similarly melted to flatten the surface.

The GeBPSG film is a material obtained by adding several weight percent of germanium (Ge) to the BPSG film described above, and its melting point can be lowered to about 800° C., making heat treatment easier.

As in the above embodiments, the formation method of the present invention is easy to form, the flattening film has good moisture resistance, contains few impurities, and, of course, does not contain organic substances. Furthermore, since the flatness is as excellent as that of the solution coating method, it is the best flattening method.

[Effects of the Invention] As is clear from the above description, according to the present invention, an insulating film with good moisture resistance and excellent flatness can be easily formed. Therefore, it is significantly useful for improving the reliability and quality of ICs.

[Brief explanation of drawings]

FIGS. 1(a) to (C1 are cross-sectional views in order of the formation process according to the present invention, and FIG. 2 is a cross-sectional view of a conventional structure. In the figures, 1 is a semiconductor substrate, 2 is a polycrystalline silicon wiring, and 3 is a PSGI !!, 4 is spin-on glass film, 5 is BPSG film @ 1 Fig. 2

Claims (1)

[Claims] A boron phosphorus silicate glass having a higher melting point or a boron phosphorus silicate glass containing germanium is deposited on the insulating film, and the boron phosphorus silicate glass or boron phosphorus silicate glass containing germanium is melted to form a surface. 1. A method for manufacturing a semiconductor device, comprising the step of planarizing the semiconductor device.