JPS609166A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To recover defective insulation by thickening a gate oxide film after forming a gate electrode, and to improve yield by thermally treating the whole in an H2 carrier gas containing H2O of 10ppm-10% within a temperature range of 500-1,200 deg.C. CONSTITUTION:A partially thick field oxide film 2 is formed on an Si substrate 1 through a well known LOCOS method. A gate oxide film 3 in 5-100nm thickness is shaped through a thermal oxidation method, and a W electrode 4 is applied selectively. Especially when there is a defect in the gate oxide film 3 and an insulation withstanding voltage defective section 5 is generated at that time, the defective section can be discriminated when currents between the W electrode 4 and the Si substrate are measured. When the presence of the insulation withstanding voltage defective section 5 is made sure after applying the W electrode 4, thermally treating the whole Si wafer, from which an integrated circuit is manufactured, in H2 containing 5% H2O under conditions such as 950 deg.C and 30min thickens the thickness of the gate oxide film 3 under a section such as the gate electrode 4 up to 20nm when the thickness of the oxide film 3 is 10nm. Accordingly, the insulation withstanding voltage defective section 5 also disappear, and excellent insulating properties are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a semiconductor device, and particularly to a novel semiconductor manufacturing method effective for improving gate electrode dielectric strength voltage.

[Background of the invention]

Generally, an extremely thin 5i02 gate insulating film with a thickness of 5 to 100 nm is used in Si integrated circuits, particularly in MO8 type integrated circuits. Because the manufacturing process for this 8i02 film is not perfect, if it is particularly thin, there may be areas with low dielectric strength between it and the KSi substrate, or in extreme cases, electrical short circuits may occur [Purpose of the Invention] ] An object of the present invention is to provide a novel method for restoring an integrated circuit whose electrical withstand voltage has become low due to a defect in the gate oxide film through subsequent processing.

[Summary of the invention]

f3i, W or MO are each oxidized when heated in an oxygen-containing atmosphere. In particular, W and MO have slower oxidation rates than Si. On the other hand, these oxides are reduced by high heat treatment in H2.

Therefore, when H2 and H2O are mixed in an appropriate ratio, there is a range of temperature and mixing ratio of H2 and H2O in which Si is oxidized and W and MO are reduced when Sl and W or MO coexist. The present invention takes advantage of this phenomenon to generate 8i02 under W+MO.
This increases the film thickness and improves electrical insulation breakdown voltage.

[Embodiments of the invention]

Embodiments of the present invention are shown in FIGS. T-2 below. As shown in FIG. 1, a partially thick field oxide film 2 is formed on a Si substrate 1 by the well-known LOCO8 (local oxidation method) method. Thereafter, a gate oxide film 3 having a thickness of 5 to 1100 nm is formed by a thermal oxidation method. Thereafter, W electrodes 4 are selectively deposited.

In this case, it is assumed that there is a defect in the gate oxide film 3, and a breakdown voltage defective portion 5 occurs. This is W electrode 4 and Si substrate 1
This can be determined by measuring the current between the two.

If the presence of the insulation breakdown voltage failure part 5 is found after the W goo 1-1 pole 4 is deposited, the entire Si wafer for making an integrated circuit is
When heat treated in H2 containing 5% H2O at 50C for 30 minutes, for example, when the gate oxide film 3 under the gate electrode 4 was 10 m thick, it became 20 m thick, as shown in Figure 2. . As a result, the defective dielectric strength portion 5 also disappeared, and good insulation was obtained.

Therefore, integrated circuits that should originally have been considered defective and rejected have been turned into good products, which has a significant effect on improving the yield of non-defective products.

In the embodiment of the present invention, the H2+H♀0 heat treatment was performed after the W gate electrode was patterned, but it can also be performed before patterning, that is, with the W gate 'ft electrode coated on the entire surface.

Furthermore, in the above embodiments of the present invention, n+ and p+
Although the case where there is no diffusion layer has been described, the above-mentioned H2+H20 heat treatment can also be performed after forming these high concentration layers.

Further, in the above embodiments of the present invention, the entire surface was exposed to the H2+H20 heat treatment, but the thicker and harmful gate insulating film was exposed to a sufficiently thick ICV D − that substantially prevents H2O from passing through.
It can also be covered with an S i 02 film or an S js N4 film.

〔Effect of the invention〕

As described above, according to the present invention, if an electrical insulation defect is discovered, the gate oxide film is thickened after the gate electrode is formed to recover from the insulation defect and produce a non-defective product, which has a significant effect on improving the yield.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views for explaining one embodiment of the present invention. 1... st substrate, 2... field oxide film, 3...
・K-) No VJ+ (2) Edai 2 (2)

Claims (1)

[Claims] 1. In a semiconductor device having an electrode made of a refractory metal or its silicide deposited on a Si substrate via a 5jO2 film, H
By heat treatment in H2 carrier gas containing 10P-10 of 2O, 5i02 between the electrode and the Si substrate is
A method for manufacturing a semiconductor device that increases the thickness of a film.