JPS60152049A - Capacitor - Google Patents

Abstract

PURPOSE:To form a large capacity for a capacitor in a smaller area by a methed a high-melting point metal film is formed on the surface of the Si substrate of the contact hole part; insulating films having a large specific inductive capacity, a second electrode, etc., are laminated thereon; the patterns are formed at one time; and a thermal treatment is performed in an oxygen atmosphere. CONSTITUTION:Interelement isolation insulating films 2, a W electrode 3 of a film thickness of about 1,000Angstrom , a Ta2O3 film 4 of a film thickness of about 300Angstrom , a W electrode 5 of a film thickness of 1,000Angstrom , an Al electrode 6 and tungsten oxide films 7 are formed on an Si substrate 1. In the manufacturing process of this capacitor, after the W film 3, the Ta2O3 film 4, the W film 5 and the Al film 6 were laminated, each film of Al/W/Ta2O3/W is performed a working for being formed into an electrode by performing a dry etching using the same photo mask. After that, a thermal treatment is performed in an oxygen atmosphere of 450 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to large-scale integrated circuits, and more particularly to small-area, large-capacity capacitors necessary for realizing large-scale integrated circuits.

[Background of the invention]

In manufacturing a conventional capacitor in which a first electrode, an insulating film, a second electrode, and an arbitrary substrate are laminated, such as a laminated capacitor cell (8TC), photo-etching is performed at the time the second electrode is laminated. , perform the second
After forming an electrode pattern, an insulating film and a first electrode pattern are formed.
At least two electrodes were stacked and photoetched again to form a capacitor.
There is a drawback that the number of manufacturing steps is large and complicated, requiring photo-etching to be performed more than once.

For example, if shown using the cross-sectional view of a capacitor in FIG.
1 is 81 substrate, 2 is element isolation insulating film, -3 is 1000
4 is a Ta205 film with a thickness of that of a human being, 5 is a W electrode, and 6 is an A4 film. In this manufacturing process,
Since there is a lower W electrode and an upper At/W electrode, the photoetching process is required at least twice, and there are drawbacks such as a reduction in the area of the capacitor due to misalignment of the photomask.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to reduce the number of manufacturing steps and to obtain good dielectric strength, particularly for small-area, large-capacity capacitors that are necessary for realizing highly integrated LSIs.

[Summary of the invention]

In the present invention, in order to reduce the photo-etching process of the electrode, high-melting point metals W, MO, etc. are formed on the Si surface of the contact hole.
Alternatively, W silicide, MO silicide, etc. are used, an insulating film Ta2051 with a high dielectric constant is formed thereon, and W is again used as the second electrode.

Sequential product of 40 silicides to MO or W silicide;
- A pattern was formed by one-time photo-etching.

However, in the capacitor, surface leakage occurs at the side surfaces of the upper and lower electrodes, and especially when the surface of the substrate is contaminated, the leakage current is large and the reliability is reduced. Therefore, the side surfaces of the electrodes were oxidized by heat treating the substrate in an oxygen atmosphere. As a result, surface leakage was eliminated, a good dielectric strength voltage was obtained, and a highly reliable capacitor with a small manufacturing process and a large capacity could be produced in cross section.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail by way of example.

In the capacitor manufacturing process, processing the upper and lower electrodes and the insulating film using the same mask is advantageous because the process can be shortened.

FIG. 2 shows a cross-sectional view of a capacitor according to the present invention. 1 is a Si substrate, 2 is an inter-element isolation insulating film, and 3 is about 1
W electrode with a film thickness of 000, 4 is Ta205 with a thickness of about 300
5 is a 1000 W electrode, 6 is an At electrode, and 7 is a tungsten oxide film. In this capacitor manufacturing process, after the W film 3, Ta20s PA 4 +WWS2 and At film 6 are laminated, electrodes are processed by etching the At/W/Ta2U3/W films using the same photomask.

Thereafter, heat treatment was performed in an oxygen atmosphere at 450 degrees Celsius.

At that time, the upper and lower W not covered by the A4 electrode
The side surfaces of the electrodes were oxidized to form tungsten oxide 7, eliminating surface leakage, providing good dielectric strength and improving reliability. At this time, the At electrode 7 was slightly oxidized. The number of manufacturing processes was significantly reduced.

In this embodiment, W was used as the canopy electrode, but the inventors were able to obtain similar effects by using at least MO, W silicide, and MO silicide in addition to W. Furthermore, a similar effect occurs when the electrode material of the capacitor oxidizes and becomes an insulator with good dielectric strength.
, Nb, LLf.

It was also obtained from Ti etc.

Furthermore, in addition to tantalum oxide, niobium oxide, nitrogen oxide, titanium oxide, aluminum oxide, silicon nitride, or the like may be used as the insulating film.

Then, a chloride gas was used for At dry etching. In addition, sufficient etching rates for W and Ta205 were obtained using SFg gas. Other fluoride gases may be used for dry etching of W and Ta205.

In the present invention, since the first electrode/insulating film/second electrode are etched using the same photomask, the number of manufacturing steps can be significantly reduced. In addition, since the base electrode can be formed on the top of the element isolation insulating film around the contact hole, it is easy to create a stacked capacitor cell (8TC) that does not increase the area of the capacitor even if there is an element isolation insulating film. can be formed into

Further, since the upper and lower electrodes of the capacitor are etched at the same time, there is an advantage that even if there is a misalignment of the mask, the area of the capacitor does not decrease.

In other words, in the conventional 8TC structure, the upper and lower electrodes of the capacitor had to be processed using different masks, so due to the f# degree problem of mask alignment, the area of the capacitor's electrode had to be designed to be large with some margin. If not, S
This was a major obstacle to the practical application of TC.

〔Effect of the invention〕

According to the present invention, the number of manufacturing steps of a stacked capacitor (STC) can be reduced and a good dielectric strength voltage can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional capacitor. FIG. 2 is a cross-sectional view of the capacitor of the present invention. 1... SL substrate, 2... Inter-element isolation insulating film, 3...
- Lower W electrode, 4... Ta2 os film, 5... Sobe W electrode, 6... AzllL7... tungsten oxide. Agent Patent Attorney Akio Takahashi

Claims (1)

[Claims] 1. A capacitor in which a first electrode/insulating film/second electrode/arbitrary substrate are laminated, wherein the side surfaces of the first and first electrodes are oxidized. A capacitor characterized by: 2. The capacitor according to claim 1, wherein the first electrode/insulating film/second electrode are etched using the same photomask. 3. The first and second electrodes are made of W, Mo, W silicide, Mo silicide, 'ra, Nb. 1. The capacitor according to claim 1, characterized in that the capacitor is constituted by: The capacitor according to claim 1, characterized in that it is made of silicon nitride. 5. The capacitor according to claim 2, characterized in that the etching method is dry etching and uses fluoride gas. 6. The capacitor according to claim 1, wherein the arbitrary substrate is -8i.