JPS6279626A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make a surface flat without the rediffusion of an impurity by increasing the power of a CVD equipment together with forming an insulation film by CVD at a temperature of the extent that no impurity in a semiconductor substrate is rediffused. CONSTITUTION:A semiconductor substrate 1 which has a rugged pattern 2 on its surface is contained in a chamber for CVD and an insulation film 4 is formed by plasma CVD at a temperature of approx. 800 deg.C. In this case, if the power of a CVD equipment is increased, sputtering effect appears and reflowing can be achieved. By increasing the power of the plasma CVD in such a way, the reflowing of the insulation film can be done at a low temperature on the semiconductor substrate 1 which has a rough pattern simultaneously with the formation of the insulation film, so the surface can be made flat without the redistribution of an impurity introduced in the semiconductor substrate.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a method for manufacturing semiconductor devices, in which the surface of a concavo-convex pattern formed on a semiconductor substrate is flattened. FIG. 3 is a sectional view showing a state at a main stage. In FIG. 2, when the uneven pattern (2) is still formed on the semiconductor substrate (1), if aluminum (Al) wiring is formed directly on it, the edges of the unevenness will be steep, so the A6 wiring However, in order to avoid this problem, flattening of the surface has been conventionally performed. That is, first, Figure 2A
As shown in the figure, the uneven pattern (2) is formed, and
A semiconductor substrate (1) having an impurity introduced region (3) therein.
), which can be reflowed using the O'VD method [e.g., phosphorus glass (PSO), boron phosphorus glass (BPS)
After that, as shown in FIG. 2B, the insulating film (4) was reflowed by heat treatment to achieve surface planarization.

[Problem that the invention seeks to solve]

In the conventional method, in order to flatten the uneven surface of a semiconductor substrate (1) having an uneven pattern (2), a reflowable insulating film (4) is formed on the uneven surface and this is reflowed at a high temperature. At this time, the required treatment at a temperature close to 1,000°C causes re-diffusion of impurities in the impurity-introduced region (3), as shown in Figure 2B, which hinders the miniaturization of semiconductor devices. There was a problem.

This invention was made to solve the above-mentioned problems, and aims to provide a method that can flatten the surface without causing impurity re-diffusion.

[Means for solving problems]

In the method for manufacturing a semiconductor device according to the present invention, the insulating film is heated to a temperature that does not cause re-diffusion of impurities in the semiconductor substrate.
In addition to VD film formation, the power of the CVP equipment is increased to perform reflow of the insulating film at the same time.

[Effect]

In this invention, by increasing the power of cvp*t, reflow ζ can be performed at a low temperature simultaneously with the formation of an insulating film.

〔Example〕

FIG. 1 is a sectional view showing a semiconductor substrate whose surface has been planarized by a method according to an embodiment of the present invention, and the same reference numerals as in the conventional example indicate equivalent parts. A semiconductor substrate (1) having an uneven pattern (2) on its surface is housed in a CVD chamber (not shown), and an insulating film (4) is formed by plasma CVD at a temperature of about 800'C. When the power of this CVD apparatus is increased, a sputtering effect appears and reflow can be achieved as shown in the figure.

Although the above embodiment deals with flattening the base to prevent disconnection of metal wiring, it can also be applied to devices with large steps between wiring such as tertiary elements.0 [Effects of the Invention] As described above, this invention By increasing the power of plasma OVD, it is possible to form an insulating film on a semiconductor substrate having an uneven pattern and simultaneously reflow the insulating film at a low temperature. 0, which is suitable for the miniaturization process because it does not cause redistribution of impurities.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing a semiconductor substrate whose surface has been planarized by a method according to an embodiment of the present invention, and FIG. 2A. B is a cross-sectional view showing the main stages of a conventional surface flattening method. In the figure, (1) is a semiconductor substrate, (2) is an uneven pattern, (3) is an impurity introduced region, and (4) is an insulating film. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (2)

[Claims] (1) A semiconductor substrate having an uneven pattern on its surface is housed in a chamber of a plasma CVD apparatus, and an insulating film is formed at a low temperature on the uneven pattern at a low temperature, and the power of the plasma CVD apparatus is increased to A method for manufacturing a semiconductor device, comprising a step of simultaneously performing reflow of the insulating film in the state. (2) The semiconductor device according to claim 1, wherein the temperature at which the insulating film is formed and reflowed using a plasma CVD apparatus is lower than the temperature at which impurities introduced into the semiconductor substrate are redistributed. manufacturing method.