JPH03257850A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make it possible to form an applied glass film, in which there are no crack and the small difference between the etching speed in a surface layer and the one in a deep layer, by repeating predetermined times the process, in which after forming the applied glass film on the substrate of a semiconductor integrated circuit, the film is preheated and after thinning the film through etching, the film is cured through annealing, and by forming a thick glass film. CONSTITUTION:A substrate wafer of a semiconductor integrated circuit, on whose surface there are formed wirings, is mounted on a spin coater. While making the spin coater rotate at a rotational frequency of 1000-5000rpm, an inorganic SOG is applied to the substrate wafer of the integrated circuit. The substrate wafer of the integrated circuit is preheated on a hot plate at 250 deg.C and in two minutes. The thickness of the SOG film in this stage is about 300Angstrom . By etching the SOG film for about 30 seconds using hydrofluoric acid, its thickness is made to be about 100Angstrom . By annealing the SOG film using a lamp at 700-900 deg.C and for about one minute, it is cured.

Description

[Detailed Description of the Invention] [Summary] The purpose of the present invention is to provide a method for forming a coated glass film that is free from cracks and has a small difference in etching rate between the surface layer and the deep layer with respect to a method for flattening an insulating film between the eyebrows. The invention involves a process of applying coated glass to a semiconductor integrated circuit board on which wiring has been formed to form a coated glass film, and then preheating the coated glass film, and etching the coated glass film to make it thin, and then annealing the coated glass film. The process of curing is repeated a predetermined number of times to form a thick coated glass film.

The second invention includes a step of applying coated glass on a semiconductor integrated circuit board on which wiring is formed to form a coated glass film, and then preheating the coated glass film, and then etching the coated glass film to thin it and then annealing it. After a step of curing the coated glass film, a series of steps consisting of coating the coated glass, preheating, and annealing is repeated one or more times to form a thick coated glass film.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and particularly to a method for planarizing an insulating film between the eyebrows.

In recent years, with the improvement in the degree of integration of semiconductor integrated circuits.

Wiring is becoming more multi-layered. In such a multilayer wiring structure, the unevenness of the lower layer wiring makes it difficult to form the upper layer wiring. Therefore, in order to facilitate the formation of the upper layer wiring, there is a need for a technique for flattening the glabella insulating film for mutually insulating the lower layer wiring and the upper layer wiring.

[Conventional technology]

As a method for flattening the glabella insulating film, there is a method using coated glass (SOG; 5 pin on glass). A conventional method for forming an SOG film will be described below.

fa) First method (2) A semiconductor integrated circuit substrate wafer with wiring formed on its surface is placed on a spin coater.

■ While rotating the spin coater, SOG is coated by dropping the stock solution of SOG onto the integrated circuit substrate wafer.
Form an OG film.

■ Breheat the SOG film.

■ Anneal and cure the SOG film.

(b) Second method The first method is a method of forming a thick SOG film with one coating, but this method is a method of forming a thin SOG film of multiple layers by repeating the steps This is a method of forming a thick 5OGWA as a layered structure of films.

(Problems to be Solved by the Invention) The first conventional method forms a thick SOG film by 51 coatings.

■Easy to insert the crank.

(2) Since the etching speed is different between the surface layer and the deep layer of the SOG film, when patterning is performed in a subsequent process, the deep layer is etched to a greater extent, resulting in a problem of deformation of the pattern shape.

There are two primary methods for forming a thin SOG film in the conventional second method.

■ A method of reducing the solid content of the SOG stock solution and increasing the proportion of solvent.

■ How to increase the rotation speed of the spin coater when applying SOG.

However, method
Non-uniformity of the stock solution occurs, resulting in portions on the wafer where the SOG film is not formed. There was a problem. In addition, method (1) has the problem that the SOG liquid accumulates in the fine grooves due to capillary phenomenon, making it impossible to thin the SOG film in the grooves.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a semiconductor device that solves these problems, particularly a method for forming a coated glass film that does not have a crank and has a small difference in etching speed between the surface layer and the deep layer.

[Means to solve the problem]

In order to achieve the above object, a method for manufacturing a semiconductor device according to the present invention, particularly a method for planarizing an insulating film between the eyebrows, is configured as follows.

The first invention includes a step of applying coated glass to a semiconductor integrated circuit board on which wiring is formed to form a coated glass film, and then preheating the coated glass film, and then annealing the coated glass film after etching it to be thin. The process of curing the coated glass film is repeated a predetermined number of times to form a thick coated glass film.

The second invention includes a step of applying coated glass onto a semiconductor integrated circuit board on which wiring is formed to form a coated glass film, and then preheating the coated glass film, and then annealing the coated glass film after etching it to be thin. After the process of curing the coated glass film, a series of processes consisting of coating the coated glass, preheating, and annealing is repeated one or more times to form a thick coated glass film.

[For production]

Here are two reasons why cranks occur when forming a thick SOC film as a single layer in a single application and heating process, as in the conventional example.
The present inventor conjectures as follows.

That is, in the solidification process after coating and forming the SOC film,
Conventionally, for example, lamp annealing has been common. However, when this lamp annealing is used, if the SOC film is thick, the heat is uniformly transmitted between the inner surface and the vicinity of the surface. By the way, the process of solidifying the SOC film is as follows. S.O.C.
The solution is.

Silanol, which is the main component of glass, is mixed into a relatively large amount of solvent, and the solvent first vaporizes when heated. Next, the silanol molecules undergo a dehydration reaction between the hydroxyl group on one side and the hydrogen on the other side, and are bonded to each other. This dehydration reaction causes the SOC film to condense. However.

There is no condensation of the SOC film on the inside where heat has not yet sufficiently transferred. For this reason, strain occurs between the relatively inner layer in the SOC film and the layer near the surface.

This is thought to lead to cracks.

Or what is the mechanism by which cranking occurs?

You can also think of it as follows.

In other words, according to the observations of the present inventor, it has become clear that even if the surface of the SOC film is flat when it is coated, when it is heated and solidified, this surface becomes depressed in a parabolic shape. There is. In other words, the surface area of the SOC film increases by the amount of the depression as it solidifies. As mentioned earlier, S
When the OC film solidifies, it condenses. Nevertheless, since the surface area increases, it can be considered that strain may occur near the surface of the SOC film.

In addition, since the SOC film first begins to solidify from the surface, the SO
When the relatively inner part of the C membrane begins to harden.

The surface of the SOC film is solidified. However, even when the inside of the SOC film hardens, moisture is still formed due to the dehydration reaction between the silanols, and this moisture tries to push through the already hardened surface of the SOC film and scatter to the outside, causing distortion and causing a crank. It is possible that this is the case.

The inventors of the present invention obtained the following knowledge while conducting experiments using a spin cord on the uneven surface of coated glass (SOC).

Figure 4 is a diagram showing the relationship between the two, with the horizontal axis representing the thickness of the thin film formed from one coating to heating process, and the vertical axis representing the thickness of the layer formed by stacking. In a certain figure 0, O indicates that no crank was determined to have occurred as a result of microscopic confirmation, and × indicates that cracks were determined to have occurred.

It can be seen from FIG. 4 that by laminating thin SOC films, it is possible to form a thick SOC film without cracks.

The present invention was made based on nine or more findings,
By sequentially stacking thin single layers of solidified SOC films, even SOGg having a large cumulative film thickness can be formed without cracking.

〔Example〕

(Refer to the first embodiment, FIG. 1) (1) A semiconductor integrated circuit substrate wafer with wiring formed on its surface is placed on a spin coater.

■ While rotating the spin coater at a rotation speed of 1000 to 5000 rpm, inorganic SO is applied onto the integrated circuit substrate wafer.
Apply G. (FIG. 1(a)) ■ Preheat the integrated circuit substrate wafer at 250° C. for 2 minutes on a real plate. (Figure 1 et al.)) The thickness of the SOC film at this stage is about 300 layers.

■ Hydrofluoric acid (for example, H, O: HF=99.5:
0°5) for about 30 seconds to a film thickness of about 100 mm. (Figure 1 (C)) ■
The socM is cured by annealing at 700-900°C for about 1 minute using a lamp. (FIG. 1(d)) The SOG film formed through the above steps had no crank, and no difference in etching rate was observed between the surface layer and the deep layer.

(Refer to the second embodiment, FIGS. 1 and 2) ① A semiconductor integrated circuit substrate wafer with wiring formed on its surface is placed on a spin coater.

■ While rotating the spin coater at a rotation speed of 1000 to 5000 rpm, inorganic SO is applied onto the integrated circuit substrate wafer.
Apply G. (Same as Figure 1(a)) ■ Place the integrated circuit board wafer on the hot plate for 25 minutes.
Preheat at 0''C for 2 minutes (same as in Figure 1 ℃) The thickness of the SOG film at this stage is about 300mm.

■ Fu #1 (for example, H, o: HF=99.5
:0°5) to etch the SOC film for about 30 seconds to a film thickness of about 100 mm. (Similar to FIG. 1(C)) (2) Cure the SOC film by annealing at 700 to 900° C. for about 1 minute using a lamp. (Same as Figure 1 (b)) ■ Repeat steps 5 to 5 to obtain a layered structure with a thickness of 50 mm.
A thick SOG film with a thickness of 0 is formed. (Figure 2) This thick 5oca had no cracks, and no difference in etching rate was observed between the surface layer and the deep layer.

(Third Example) (1) A semiconductor integrated circuit substrate wafer with wiring formed on its surface is placed on a spin coater.

■ While rotating the spin coater at a rotation speed of 1,000 to 5,000 rpm, coat the integrated circuit substrate wafer with m5O.
Apply c. (Same as Figure 1(a)) ■ Place the integrated circuit board wafer on the hot plate for 25 minutes.
Preheat at 0''C for 2 minutes (same as in FIG. 1(G)) The thickness of the SOG film at this stage is approximately 300 mm.

■ 77 acid (e.g. +1.0: HF=99.5
:0°5) to etch the SOG film for about 30 seconds to a film thickness of about 100 mm. (Similar to FIG. 1(C)) (2) Cure the SOC film by annealing at 700 to 900° C. for about 1 minute using a lamp. (Same as Fig. 1 (cl)) ■ While rotating the spin coater at a rotation speed of 1000 to 5000 rpm, coat the integrated circuit substrate wafer with 5ts.
Apply oc.

■ Place 25 integrated circuit board wafers on a hot plate.
Preheat at 0°C for 2 minutes.

(2) Cure the SOC film by annealing at 700-900''C for about 1 minute using a lamp.

■ Repeat the steps from ■ to ■ 5 times until the thickness of the laminated structure is 50 mm.
A thick SOG film with a thickness of 0 is formed. (FIG. 3) This thick SOC film had no cracks, and no difference in etching rate was observed between the surface layer and the deep layer.

〔Effect of the invention〕

According to the present invention, it is possible to form a coated glass film without a crank and with a small difference in etching rate between the three surface layers and the deep layer. Therefore, a glabellar insulating film with excellent flatness can be formed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the first embodiment. Figure 2 is a diagram showing the second embodiment. FIG. 3 is a diagram showing the third embodiment. Figure 4 is a diagram showing the relationship between the thickness of one coated film and the cumulative film thickness. It is.

Claims (2)

[Claims] (1) A process of applying coated glass onto a semiconductor integrated circuit board on which wiring has been formed to form a coated glass film, and then preheating the coated glass film, and then etching the coated glass film to make it thinner and then annealing it to form the coated glass film. 1. A method of manufacturing a semiconductor device, comprising: repeating a step of curing a predetermined number of times to form a thick coated glass film. (2) A process of applying coated glass on a semiconductor integrated circuit board on which wiring has been formed to form a coated glass film, and then preheating the coated glass film, and etching the coated glass film to make it thinner, and then annealing and forming the coated glass film. 1. A method for manufacturing a semiconductor device, characterized in that after a step of curing the coated glass, a series of steps consisting of coating the coated glass, preheating, and annealing is repeated one or more times to form a thick coated glass film.