JPS6273741A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To microminiaturize a contact or through hole by opening an insulating film by photolithography, then uniformly bonding the second insulating film having different etching rate on the entire substrate, and then removing by anisotropically etching only the flat portion of the second film. CONSTITUTION:An insulating film I103 is formed on a conductor wiring 102 on a silicon substrate 101, the surface is coated with a photoresist, and a hole is opened. Then, with the photoresist 104 as a mask the film I103 is opened by anisotropically etching without side etching. Then, after the photoresist 104 is removed, an insulating film II106 is accumulated in a uniform thickness by different etching rate from the film I103 on the entire substrate. Subsequently, only the portion adhered to the surface substantially parallel to the substrate 101 of the film II106 is removed by anisotropically etching. Thus, the insulator II106 remains on the side 105 of the hole of the insulator I103, and a fine through hole can be formed beyond the limit of the photolithography by ultraviolet ray exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing an integrated circuit device having a step of forming fine contacts and through holes.

[Conventional technology]

Conventionally, contacts in an insulating film on a semiconductor region of an integrated circuit device and through holes in an insulating film on wiring have been formed on a silicon substrate 301, for example, as shown in FIGS. Insulating film 3 on conductor wiring 302
In 03, photoresist 304 was completely coated by photolithography using ultraviolet exposure sound! +305 holes were drilled.

[Problem that the invention seeks to solve]

The method for forming contacts and through holes in integrated circuit devices described above uses current photolithography using ultraviolet light, so there is a limit to the dimensions that can be exposed depending on the wavelength of the light.
There was a drawback that it was impossible to form holes with a good overall yield (m0 or less). Therefore, there was a drawback that it was difficult to fabricate an integrated circuit device with a high degree of integration and high wiring density.2 The present invention eliminates the drawbacks of the above-mentioned conventional method, and uses photophosphorography using ultraviolet light exposure. It is an object of the present invention to provide a method for manufacturing a semiconductor device that can easily form fine contacts or through-holes that exceed the limits of semiconductor devices and with a high yield.

[Means for solving problems]

The method for manufacturing a semiconductor device of the present invention includes - a step of forming holes using photolithography in an insulating film on a different semiconductor region provided on one principal surface of a semiconductor substrate having a conductivity type or on an insulating film on a conductor wiring; and a step of uniformly forming a second insulating film having an etching rate different from the insulating film over the entire substrate including the opening, and removing only the flat part of the second insulating film by anisotropic etching. The process includes the steps of:

〔Example〕

Next, the present invention will be explained with reference to all the drawings.

Figures 1 (al to d) are cross-sectional views shown in the order of steps to explain the first embodiment of the present invention. In the first embodiment, fine through holes are formed in the insulating film on the wiring. An example applied to the method will be explained.

First, as shown in FIG. 1 (a+), the silicon substrate 101
An insulating film 1103t- is provided on the upper conductor wiring 102.

Next, photoresist '6 is applied to the surface and openings are formed.

Next, as shown in FIG. 1('b), the photoresist 1
04'1 is subjected to anisotropic etching using a mask, and the insulating film 11031CIJ hole is formed so as to avoid side etching. In such a case, the side surface 105 of the opening of the insulating film 103
is almost perpendicular to the silicon substrate 101.

Next, as shown in FIG. 1 (C1), a photoresist 10
After removing 4, low pressure CVD (LPCVD) is applied to the entire surface of the substrate.
), it is a film with very good coverage, and is an insulating film.
An insulating film n1Ofl having a different etching rate from 103.
Deposit with uniform thickness.

Next, as shown in FIG.
Of these, only the nine portions attached to the surface substantially parallel to the silicon substrate 101 are etched using reactive fist ions or etching (RI).
υ is removed by anisotropic etching such as E). A so-called etch pack method is used. As a result, insulator ■10
An insulator 106 remains on the side surface 105 of the opening 3, and thus a fine through hole can be created by pushing the limits of photolithography using ultraviolet light exposure.

Figure 2 fat~(el is a cross-sectional view shown in the order of steps to fully explain the second embodiment of the present invention.The second embodiment is applied to a method of forming tapered fine through-hole metal on wiring. An example will be explained below.

First, as shown in FIG.
An insulating film I 203 is formed on the upper conductor wiring 202, and an insulating film lI2 having an etching rate different from that of the insulating film I is formed thereon.
04e will be provided. Next, a photoresist 205 having an opening is formed in the insulating film (1) by photolithography.

Next, as shown in FIG. 2(b), only the insulating film 204 is etched by IJ lithography to form a hole.

At this time, etching money is applied so that the side surface 206 of the opening of the insulating film 204 is tapered.

Next, as shown in FIG. 2 (C1), holes are formed in the insulating film 1203 by anisotropic etching without side etching in the same manner as in the first embodiment. The side surface 207 of the opening is located on the silicon substrate 20.
It is almost perpendicular to 1.

Next, as shown in FIG. 2 Fdl, a photoresist 20
After removing 5, a film with very good coverage is formed on the substrate surface by a method such as LPGVD, and the insulating film I
An insulating film llI2 with a different etching rate from the insulating film ■
08f: Deposited with uniform thickness.

Next, as shown in FIG. 2 (61), only the portion of the insulating film 208 attached to the surface substantially parallel to the silicon substrate 201 is removed by anisotropic etching such as RIE. The insulating material 208 remains on the side surface 207 of the I2O3 opening, and it is possible to form a fine through-hole gold that is fine and tapered beyond the limits of photolithography using ultraviolet exposure.

Therefore, when the second conductor wiring or the like is placed over it, it can be expected that the breakage at the end of the through hole will be reduced.

〔Effect of the invention〕

As explained above, the present invention uniformly deposits an insulator using photolithography. Then, by etching back only the latter insulator using anisotropic etching, leaving the latter insulator only on the sides of the contact or through hole, we can create fine contacts that exceed the limits of photolithography using ultraviolet exposure. , or through-holes can be formed easily and with high yield.

[Brief explanation of drawings]

Figure 1 (al~(dl) is a sectional view shown in the order of steps to explain the first embodiment of the present invention, Figure 2 (tai~fel)
101, 201 are cross-sectional views shown in the order of steps to fully explain the second embodiment of the present invention, and FIGS. 3A and 3B are cross-sectional views shown in the order of steps to fully explain the conventional method. , 301... Silicon substrate, 102, 20 302... Conductor wiring, 103
, 203... Insulating film I, 303... Insulating film, 104, 205, 304... Photoresist, 106, 204... Insulating film processing, 105 ，
207...:... Side surface of the opening of the insulating film ■, 206...
. . . Side surface of opening of insulating film 1■, 305 . . . Opening, 208 . . . Insulating film L209 . Agent Patent Attorney Susumu Uchihara 1 Zo 2 So 1 2θ/Goto Kari Iki no T A… Norikao 7. Group

Claims (1)

[Claims] A first step of forming a hole by photolithography in an insulating film on a different semiconductor region or an insulating film on a conductor wiring provided on one main surface of a semiconductor substrate having one conductivity type;
a second step of forming a second insulating film having a different etching rate from the insulating film over the entire substrate including the opening;
and a third step of removing only the flat portion of the second insulating film by anisotropic etching.