JPH01192134A - Manufacture of semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor device, and particularly to a technique for forming a taper into a fine contact.

(Prior Art) Currently, contact holes are formed in a multilayer interconnection process by patterning contacts as shown in FIG. The wiring in the first layer and the wiring in the second layer are electrically connected.

However, with this technique, if the contact hole becomes small, AQ may not be able to enter the contact and AQ may be cut off.

B For this reason, as shown in Figure 4, measures were taken to prevent the insulating film from being cut off at the taper angle and preventing Al1 from entering the bottom of the contact by etching the insulating film isotropically through the contact hole. ing. As a method for forming a taper angle in this contact hole, Vat etching or CDE (chemical dry etching) is used using a resist as a mask.

However, when the contacts become fine, a problem arises in that the VAT etching solution cannot penetrate sufficiently and the necessary taper angle cannot be obtained. One reason for this is that the resist is hydrophobic to the etching solution. For this reason,
For patterns such as contact holes, this problem is exacerbated by the high resist coverage. Furthermore, as the contact dimensions become smaller, resist scum during resist patterning tends to remain at the bottom of the contact, making this problem more pronounced.

(Problems to be Solved by the Invention) An object of the present invention is to provide a method for manufacturing a semiconductor device that can form a taper angle necessary for a fine contact hole.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides unevenness by sputter etching an insulating film to be a contact hole using a Freon-based or argon-based gas, and then makes the insulating film isotropic by Vat etching. This method of manufacturing a semiconductor device is characterized by comprising a step of etching the insulating film anisotropically using a resist as a mask.

(Function) According to the present invention, the resist scum remaining at the bottom of the microcontact is etched by sputter etching of freon and argon radicals, and the insulating film also has unevenness, which improves the wettability of the etching solution. Wet etching solution can penetrate sufficiently.

(Embodiment) An embodiment of the present invention will be explained using FIGS. 1 to 4.

First, a Si substrate (for example, a P-type substrate with a surface orientation of 10o) is prepared, and after depositing, for example, 800 Al parts of the rear cylinder 1 on which a thermal oxide film (2) has been formed, the first Af
The first A is patterned by 0-order RIE for patterning
selectively etching t■, removing the resist, depositing t) on the insulating film, performing a planarization process on the insulating film), patterning the contact, and selectively leaving the resist 1.0 Next, for example, freon-based The resist scum (2) remaining at the bottom of the contact can be removed by sputter etching using the gas. In addition, the exposed insulating film has an uneven surface shape of 0. If the insulating film is etched with a primary Vat etching solution using the resist (■) as a mask, the insulating film is etched isotropically and the taper angle is At this time, the area to be etched has an uneven shape, so that the etching liquid has good wettability, so that the etching liquid can sufficiently penetrate into the small contact hole.

Thereafter, by etching the insulating film anisotropically using, for example, reactive ion etching (RIE) using the resist (1) as a mask, a contact hole having a tapered angle as shown in FIG. 2 is formed.

Next, by sputtering the second Affi*, patterning it by a photo engraving process, and etching it, a shape as shown in FIG. 3 can be obtained.

〔Effect of the invention〕

According to the present invention, since the insulating film to be etched before the 1let etching for forming a taper angle in the contact hole has an uneven surface, the wettability of the etching solution is improved and the etching solution can easily enter the etching layer, making it easy to etch the insulating film. be done. Therefore, it is suitable for high integration because it can sufficiently handle fine contacts.

[Brief explanation of the drawing]

It is a sectional view showing a conventional example. In the figure, 1...Si substrate 2...Thermal oxide film 3...
・First AM wiring 4...Insulating film 5...Resist ゛6...Insulating film surface with unevenness 7...Second l wiring ℃ 勺

Claims (3)

[Claims] (1) A step of forming a first layer of wiring on a semiconductor substrate, a step of depositing and planarizing an insulating film on the first layer of wiring, and a step of coating a photosensitive material on the insulating film. , a step of patterning a contact hole by a photo engraving process, and a step of isotropically etching a part of the insulating film with a wet solution after surface-treating the insulating film exposed by the photosensitive material as a mask. and forming a contact hole by reactive ion etching using the photosensitive material as a mask;
A method for manufacturing a semiconductor device, comprising the step of forming a second layer of wiring. (2) The method of manufacturing a semiconductor device according to claim 1, wherein the contact hole is a contact hole of 2.0 μm or less. (3) The method of manufacturing a semiconductor device according to claim 1, characterized in that when surface-treating the insulating film using the photosensitive material as a mask, sputter etching is performed using a Freon-based gas and an Argon-based gas.