JPH0669361A - Semiconductor device and its manufacture - Google Patents

Abstract

PURPOSE:To prevent deposits such as phosphorus, etc., from occurring on the surface of an insulating film by providing an insulating moisture-absorption- resistant film on the interlayer insulating film doped in high concentration with hygroscopic impurities. CONSTITUTION:An applied film 3 is made as an interlayer insulating film so as to cover the first conductor pattern made on a semiconductor substrate 1. This applied film 3 can be gotten by rotationally applying spin-coat agent consisting of silanol. Moreover, this applied film 3 is doped with phosphorus about 5mol% or more in terms of, for example, P205, for prevention of cracking. Moreover, a nitride layer 4, 10-100Angstrom thick is made on this surface exposing the surface of this applied film 3 to nitrogen plasma. Deposits such as phosphoric acid, etc., can be prevented on the surface of a film by preventing the moisture absorption of the applied film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a semiconductor device having a multilayer wiring structure and a method of manufacturing the same.

[0002]

2. Description of the Related Art In order to realize a multi-layer wiring structure, it is necessary to electrically insulate between an upper layer wiring and a lower layer wiring, and to flatten the surface to prevent unevenness due to the lower layer wiring. As an example thereof, there is a method of improving the flatness by spin-coating a spin-coating agent made of silanol and curing it by heat treatment at 150 ° to 450 ° C. to form a coating film.

FIG. 2 is a sectional view of a device for explaining a conventional method of forming an interlayer insulating film. First, Figure 2
As shown in (a), a first conductor pattern 2 is formed on a silicon substrate 1 on which elements (not shown) are formed, and a first conductor pattern 2 is formed on the substrate 1 so as to cover the first conductor pattern 2. A spin coating film 3 made of silanol is formed as an interlayer insulating film. Then, as shown in FIG. 2 (b), on the coating film 3,
The second conductor pattern 5 is formed.

The flattening method using the coating film 3 has the characteristic that the convex portions of the base are thin and the concave portions are thick, and this is used for flattening the interlayer insulating film, but it is thickened. If it is too large, cracks tend to occur during the subsequent heat treatment. Therefore, a method of doping phosphorus is widely used to suppress cracks. That is, by doping phosphorus, the stress at the time of forming SiO2 is relieved, and cracks are less likely to occur even in a thick portion.

[0005]

The conventional semiconductor device and the manufacturing method thereof are configured as described above, and the occurrence of cracks is suppressed by doping the coating film with phosphorus. A thicker coating film can be formed proportionately, and the flatness can be further improved. However, if the phosphorus concentration is about 4 mol% or more in terms of P2O5, the surface of the insulating film will absorb moisture after forming the film. Precipitate such as phosphoric acid is generated on the surface, which becomes particles and causes poor patterning of the upper wiring layer, erosion of wiring, and other reliability problems. Therefore, 4 mol% or more cannot be added. There was a problem that there was a limit.

The present invention has been made in order to solve the above-mentioned problems, and prevents the coating film from absorbing moisture to prevent the generation of precipitates such as phosphoric acid on the film surface. It is an object of the present invention to obtain a semiconductor device capable of performing the above-mentioned process, and further to provide a manufacturing method suitable for this device.

[0007]

A semiconductor device according to the present invention is provided with an insulating moisture-absorption-resistant film such as a thin nitride layer on the surface of an interlayer insulating film doped with a hygroscopic impurity at a high concentration. is there.

In the method of manufacturing a semiconductor device according to the present invention, the interlayer insulating film doped with a high concentration of impurities such as phosphorus is processed in a nitriding atmosphere to form a thin nitride layer of about 10 to 100 angstrom on the surface thereof. It is something that is done.

[0009]

In the present invention, since an insulating film such as a nitride layer is formed on the surface of the interlayer insulating film, it has excellent moisture absorption resistance. Therefore, an insulating film doped with 4 mol% or more of phosphorus is used. Even if used, particles due to precipitates such as phosphoric acid do not occur on the surface.

[0010]

EXAMPLES Example 1. 1 (a) to 1 (c) are schematic device sectional views for explaining an embodiment of the present invention, in which the same reference numerals as those in FIG. It is a nitride layer formed in.

Next, the manufacturing method will be described. First, as shown in FIG. 1 (a), a first substrate formed on a semiconductor substrate 1
A coating film 3 is formed as an interlayer insulating film so as to cover the conductor pattern 2 of. The coating film 3 is obtained by spin coating a spin coating agent made of silanol.
The coating film 3 is doped with phosphorus in an amount of, for example, about 4 mol% or more in terms of P2 O5 in order to suppress cracks.

Next, the surface of the coating film 3 is exposed to nitrogen plasma to form a nitride layer having a thickness of 10 to 100 angstroms on the surface (FIG. 1 (b)).
). To expose to nitrogen plasma, for example, using a vacuum chamber in which parallel plate type electrodes are provided inside, a nitriding gas having a gas pressure of 0.3 Torr at a temperature of 300 ° C. and a flow rate of 1000 SCCM is used, and a high frequency power source is used. A voltage of 400 KHz and an output of 400 W are applied between the electrodes. As a result, nitrogen plasma is generated in the vacuum chamber. Then, the substrate 1 shown in FIG. 1A is placed in this nitrogen plasma atmosphere for 10 minutes. On the inter-layer insulation film 3 thus formed, a second conductor pattern 5 is formed as shown in FIG. 1 (c).

As described above, according to this embodiment, since the nitride layer 4 having excellent moisture absorption resistance is formed on the surface of the coating film 3, even if the coating film is doped with 4 mol% or more of phosphorus, the coating is performed. No phosphorus deposit is generated on the surface of the film 3. Therefore, the coating film 3 can be formed thicker without the occurrence of cracks, and the flatness can be further improved.

Example 2. In the first embodiment described above, the coating film is used as the interlayer insulating film, but in this embodiment, the interlayer insulating film is formed by using the CVD method. The BPSG film is made of Si doped with boron and phosphorus.
It is formed by depositing an O2 film by the CVD method (Chemical Vapor Deposition). After that, the film obtained by the CVD method is annealed at a high temperature to change it into a liquid state, and this is made to flow on the surface of the substrate to smooth the unevenness.

In the BPSG film, phosphorus and boron have a function of causing strain in the silica network and lowering the glass transition temperature of the SiO2 film. In this case as well, BP is used.
When the phosphorus concentration of the SG film becomes 9 mol% or more, phosphorus is eluted and the film becomes highly hygroscopic and unstable. So BPS
After the G film is annealed at a high temperature, the surface is exposed to a plasma of nitrogen to form a nitride layer having excellent moisture absorption resistance of 10 to 100 angstrom on the surface of the BPSG film to prevent the elution of phosphorus. The same effect as can be obtained.

In the above embodiment, phosphorus and boron are described as an example of the hygroscopic impurities to be doped into the interlayer insulating film, but an interlayer insulating film doped with other hygroscopic impurities is also used. Even in such a case, the same effect can be obtained.

[0017]

As described above, according to the present invention, since the nitride layer having good moisture absorption resistance is formed on the surface of the interlayer insulating film,
For example, even if an interlayer insulating film having a high hygroscopic property doped with 4 mol% or more of phosphorus is used, phosphorus deposits are not generated on the film surface, and a highly reliable semiconductor device can be obtained.

[Brief description of drawings]

FIG. 1 is a device sectional view showing a manufacturing process of a semiconductor device according to an embodiment of the invention.

FIG. 2 is a cross-sectional view showing a manufacturing process of a conventional semiconductor device.

[Explanation of symbols]

 1 Silicon Substrate 2 First Conductor Pattern 3 Coating Film 4 Nitride Layer 5 Second Conductor Pattern

Claims (3)

[Claims] 1. A semiconductor device comprising a lower wiring layer arranged on a substrate and an upper wiring layer arranged on the lower wiring layer via an interlayer insulating film, wherein a high hygroscopic impurity is contained in the semiconductor device. A semiconductor device, wherein an insulating moisture-absorption-resistant film is provided on the interlayer insulating film doped with. 2. A method of manufacturing a semiconductor device, comprising the step of forming an upper layer wiring layer after forming an interlayer insulating film on a lower layer wiring layer arranged on a substrate, wherein a lower layer wiring layer formed on the substrate is formed. A method of manufacturing a semiconductor device, comprising: a step of forming an interlayer insulating film that is highly doped with an impurity having a hygroscopic property; and a step of forming an insulating hygroscopic resistant film on the surface of the interlayer insulating film. 3. The method for manufacturing a semiconductor device according to claim 2, wherein in the step of forming the insulating moisture-absorption-resistant film, the surface of the interlayer insulating film is formed into a nitride layer by exposing the interlayer insulating film to a nitriding atmosphere. A method of manufacturing a semiconductor device, comprising: