JPS5848439A - Semiconductor integrated circuit device - Google Patents

Abstract

PURPOSE:To obtain the interlayer insulating film having excellent dampproof property, reliability and patterning property of aluminum wiring layer by a method wherein on a film such as a silica film, for example, a structure on which a silicon oxide film or a phosphosilicate glass film thicker than the above film is grown by performing a vapor-phase growing method or a plasma growing method. CONSTITUTION:The silicon oxide film 8 or a low density PSG film which is thicker than the silicon film is grown in approximately 1mum thickness by performing a vapor-phase growing method. The silicon oxide film formed by a vapor-phase growing method lacks uniformity in its film thickness due to the shape of the underlying layer and the more the stepping becomes larger, the more the nonuniformity of the film thickness is generated, but as a lessening (flattening of a step) of the stepping has been performed by a silica film, the silica oxide film 8 of uniform surface can be grown. As the silica oxide film formed by a vapor-phase growing method lacks density, a control hole is bored by performing a photoresist processing after a heat treatment, an aluminum vapor-deposition is then performed, and an element is formed by patterning the aluminum wiring 9 performing a photoresist processing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor integrated circuit device, and particularly to the structure of an interlayer insulating film thereof.

As the glabellar insulating film, a silicon oxide film formed by thermal oxidation, a silicon oxide film formed by vapor phase growth, or a phosphosilicate glass film formed by vapor phase growth are used, but as device dimensions become smaller, phosphosilicate glass Phosphorusilicate glass (hereinafter referred to as high-concentration PEG) with a high phosphorus concentration (the molar concentration of pzOs is 1Q mol- or more) is used to alleviate the level difference by taking advantage of the fact that it softens during heat treatment and has fluidity. It is often used. However, the structure in which aluminum wiring is formed on high concentration PSG has poor moisture resistance. This is because when moisture penetrates from the outside, phosphoric acid (H3PO3) is generated by the highly concentrated PSG and water, corroding the aluminum and causing wire breakage in the aluminum. Therefore, when this structure is used, high reliability cannot be guaranteed unless the element package is made of a material (for example, ceramic) that allows very little moisture to penetrate. Furthermore, in order to reduce manufacturing costs, it is desirable to use inexpensive plastic packages rather than expensive ceramic packages, but since moisture can penetrate into plastic packages, they cannot be used unless the device itself has high moisture resistance. do not have. Therefore, in order to improve the moisture resistance of the element itself, the structure in which aluminum wiring is formed on the high concentration psg4 should not be used.

, in order to measure the temperature at each point, it is necessary to apply a monoconcentration of PEG (the molar concentration of P2O5 is 4' to 5ThOJ%) or an oxide film by vapor phase growth on the high I11 degree P.
'The purpose can be achieved even if the structure is made up of layers of elementary films. However, the higher the phosphorus concentration, the higher the etch rate during buffering, so the 7. If buffered fusic acid is used in the steps before Lumini and Lamb evaporation, the side etch of the upper layer silicon oxide film and the lower layer of high concentration PEG will be large, resulting in overhang and breakage of the aluminum layer. This is not an appropriate way to wake up. In addition, if an insulating film is formed using only low concentration PSG, the low concentration PSG is less prone to softening during heat treatment than high concentration PSG, but high pressure oxidation is used to soften the low concentration PSG and alleviate the step difference. However, the softening of low-concentration PEG does not occur as much when all high-concentration PSG is used, but a sufficient effect of alleviating the level difference cannot be obtained. Moreover, in this case, other wiring layers formed of polysilicon or the like are also oxidized at the same time, resulting in rounding and an increase in layer resistance, which greatly affects other characteristics of the high-pressure acid method.

A silicon oxide film is prepared by dissolving a silicon compound in an organic solvent, which is applied by spin coating or dip coating, and then subjected to heat treatment to bake a silicon oxide film. Since it is a liquid, choosing a material with an appropriate viscosity can more effectively alleviate differences in level. It is also possible to form an interlayer insulating film by applying this silica film thickly, but if it is spread too thickly, cracks will easily occur during firing. It no longer functions as a membrane. Therefore, forming an interlayer insulating film using only a silica film is not preferable for stable manufacturing.

The present invention solves the above-mentioned drawbacks and provides a semiconductor integrated circuit device having an interlayer insulating film having a structure capable of achieving a sufficient level difference mitigation effect and also having good moisture resistance and high reliability. 2. The feature of the present invention is that it has two or more Q wiring layers. As an interlayer insulating film in conductor collections and integrated circuit devices! Cloth - A coating mainly composed of 2 carbon oxide formed by a baking method, for example, on a silica film by vapor phase growth or by a plasma growth method. Does it have an insulating film with a structure grown by thicker silicon oxide film or phosphorus silicate film? Semi-conductor integrated circuit black.

Hereinafter, the present invention will be explained with reference to Examples and 51 drawings. do. An example is an N-channel silicon or congate insulated gate field effect transistor.

Figure 1: 1st pictureless 1nH,il! N-type impurities (
For example, when forming a diffusion layer for arsenic*) t-implantation, 4
．． , q section C diagram. Ion implantation is usually done by implanting a thin oxide film (after it has grown) on the substrate.1.
The thickness of this oxide film must be sufficiently thin for the projected range (lip) of implanted atoms. If a rainbow silica film is coated on this thin oxidized film and fired, the impurities contained in the silica film may diffuse into the semiconductor single-piece substrate and deteriorate the device. In order to suppress the influence of impurity diffusion, oxidation is performed after ion implantation to grow an oxide film 6 of approximately 1000X on the substrate.
゛Figure 3: Next, apply the silica film 7 to 2,000 to 300
Spin coating is performed so that it lasts for 0 hours. 4. Due to its viscosity and surface tension, the filter is applied thickly at the bottom of the step and thinly at the top to soften the step. Next, the silica film is heat treated. However, in order to prevent cracks and sounds from occurring, it is necessary to perform the heat treatment in two stages.

The first stage is to volatilize the solvent and remove it.
Heat treatment is carried out for 3 q minutes or more in a nitrogen or odor atmosphere at 0°C to 200°C. The purpose of the second stage is acid, chloride, and baking of the silicon film, and heat treatment is carried out in a nitrogen atmosphere of 1000°C or more for 30 minutes or more. I do. As described above, it is possible to obtain an arsenic oxide film having two properties similar to those of silicon oxide and a wooden horse by O-energization treatment and a thermal oxidation method. , -1,, 1. Figure 4: Next, a silicon oxide film 8A is grown using a vapor phase growth method at a concentration of P8GI.
Grow the Il to a thickness of about 1 μm using the Rica film. Silicon oxide films grown using the vapor phase growth method vary in uniformity in the thickness of the grown film depending on the shape of the underlying layer, and the larger the step, the more likely it is that uneven film thickness will occur. ), it is possible to grow a uniform silicon oxide film 8 on the surface.

Figure 5: The silicon oxide film deposited by vapor phase growth lacks density up to i, so after applying heat treatment, contact holes are opened using a photoresist process, aluminum evaporation is performed, and the photoresist is Aluminum layout depending on the process! ! 9t-Patterning to form elements.

In addition, in order to prevent overhang from occurring due to the difference in etching rate due to buffered hydrofluoric acid when forming contact holes, a silica film that does not contain additives such as phosphorus is used, and vapor phase growth is performed on it. Low concentration of P
It is comparatively fruitful to grow 8G.

By the method described above, it is possible to obtain an interlayer insulating film that is excellent in moisture resistance, reliability, and patterning properties of aluminum wiring layers.

[Brief explanation of the drawing]

+ Figure 1 is a cross-sectional view of the device after forming the base diffusion layer 3 in the source/drain region, and Figure 2 is a cross-sectional view of the device after the oxide film 6 has been grown in the source/drain region by thermal oxidation. 3 is a cross-sectional view after a silica film 7 has been applied and heat treated, and FIG. 4 is a cross-sectional view after a silicon oxide film 8 has been grown on the silica film by vapor phase growth. The cross-sectional view, FIG. 5, is a cross-sectional view of the element after patterning of the aluminum wiring has been completed. In the figures, 1... silicon substrate, 2...
...+ Thermal oxide film by selective oxidation, 3...N diffusion layer, 4
...Polysilicon gate electrode, 5...
Thin silicon oxide film during ion implantation, 6... Silicon oxide film additionally formed by thermal oxidation method, 7... Silica film, 8... Formed by vapor phase growth method 9...aluminum wiring. $svJ

Claims (1)

[Claims] In semiconductor integrated circuit devices with two or more wiring layers,
As an interlayer insulating film, a silicon oxide film or (
A semiconductor integrated circuit device/equipment characterized by having an insulating film having a structure in which a silicon silicate glass film is grown.