KR970006929B1 - Preparation process of metal wiring of semiconductor devices - Google Patents

Abstract

A manufacturing method of metal wiring in semiconductor apparatus comprising the step forming photoresist patterns having wider width than portion determined to wiring on metal layer formed on prescribed substrate; and the step etching said metal layer by using said photoresist patterns as mask and simultaneously dry etching said photoresist patterns in horizontal directions is disclosed. Thereby, it is possible to form fine pattern less than 0.4um without separate process.

Description

Method for manufacturing metal wiring of semiconductor device

1 is a cross-sectional view of a semiconductor device metallization according to an embodiment of the prior art.

2 is a cross-sectional view of a semiconductor device metallization in accordance with another embodiment of the prior art.

3A and 3B are manufacturing process diagrams of metal wirings of a semiconductor device according to the present invention.

* Explanation of symbols for main parts of the drawings

10,20,30: semiconductor substrate 12,22,32: tungsten layer,

14,24,34: photoresist pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal wiring of a semiconductor device, and in particular, by using an etching selectivity difference in a dry etching process, the photoresist pattern may be etched simultaneously with the metal wiring to form a simple metal wiring. The present invention relates to a method for manufacturing metal wiring of a semiconductor device.

Generally, the metal wiring of a semiconductor device uses sputtering-A1 which is low in resistance and easy to form. However, as semiconductor devices become more integrated, the aspect ratio, which is the ratio of the height and diameter of the metal wiring contact hole, increases, and the size of the contact hole decreases, resulting in fine sputtering-A1, which has poor step coverage. Metal wiring is becoming increasingly difficult to form.

The methods that are being studied to solve these problems are as follows.

First, as a method of using tungsten (W) having excellent deposition selectivity for silicon and oxide films, selective deposition or surface deposition of a W layer formed by a low pressure CVD method using a mixed gas of WF ₆ and SiH ₄ . To fill the contact hole, and then form a metal wiring with sputtering-A1

Secondly, as the W deposition method, the metal wiring itself is replaced with W.

Third, there is a method of forming metal wiring using A1 formed by a metal organic CVD (metal organic CVD) method having excellent step coverage.

In addition, since Al, W, etc., which are used as metal wirings, have a large light reflectance, it is difficult to accurately form the photoresist pattern due to diffuse reflection during the exposure process for forming the photoresist pattern. Although a tri-layer resist method has been devised, there is a complicated process.

Recently, tungsten excellent in electron transfer (elotron miglation) characteristics and step coverage is used for highly integrated semiconductor devices, and a pattern of about 0.35 μm is limited by conventional methods such as i-ray steppe.

Therefore, a pattern having a size of about 0.35 to 0 30 µm is realized by the above-described three-layer photosensitive film method or a design method using a silicidation step of injecting silicon atoms into the upper surface of the photosensitive film. However, these methods have a problem in that the process is complicated, there is no process margin, and the productivity and yield are low, such as requiring a separate equipment.

In addition, in order to form a fine pattern having a size of 0.3 μm or less, an exposure mask is used as a phase reversal mask or an X-ray exposure method has been studied, but there are also problems in that mass productivity and yield are different.

FIG. 1 shows the formation of metal wirings in a semiconductor device according to the prior art, which is an example of tungsten wiring formation.

After the tungsten layer 12 and the photoresist pattern 14 are formed on the semiconductor substrate 10, the tungsten layer 12 isotropically etched by the photoresist pattern 14 to isotropically etch the tungsten layer 12 wiring. It is sectional drawing of the state formed. In the etching method, the photosensitive film pattern 14 is not etched, and the tungsten layer 12 is isotropically etched by a dry or wet etching method.

Tungsten wires formed by the isotropic etching as described above have a large difference in width between the lower and upper portions of the wires, thereby increasing the electrical resistance, and having poor electrical characteristics.

As a method for solving the above problems, as shown in FIG. 2, the tungsten layer 22 formed on the semiconductor substrate 20 may be a dry etching method using the photoresist pattern 24 as a mask. Anisotropic etching was performed to form the tungsten layer 22 wiring. In this case, the photoresist pattern 24 is also horizontally etched together during the anisotropic etching.

As described above, the tungsten wiring formed by anisotropically etching the tungsten layer together with the horizontal etching of the photosensitive film pattern has a wider bottom width, and the tungsten wiring is wider than the photosensitive film pattern, thus making it difficult to form a fine pattern.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to fabricate a semiconductor device capable of forming a finer tungsten wiring than the photosensitive film pattern by isotropically etching the tungsten layer and simultaneously etching the photosensitive film pattern. In providing.

A semiconductor device according to the present invention for achieving the above object. A feature of the manufacturing method is a method of manufacturing a semiconductor device in which a metal wiring is formed by performing an etching process using a photosensitive film pattern as a mask, wherein the photosensitive film pattern protects a larger area than a portion intended for wiring on the metal layer formed on the substrate. Forming a metal wiring by isotropically etching the metal layer using the photosensitive film pattern as a mask and horizontally etching the photosensitive film pattern to form finer wiring than the photosensitive film pattern.

Hereinafter, a method of manufacturing a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B are process charts for manufacturing metal wirings of a semiconductor device according to the present invention, and are examples of tungsten wirings.

First, a tungsten layer 32 having a predetermined thickness is formed on the semiconductor substrate 30, and then a photosensitive film pattern 34 is formed on the turnsten layer 32 so that a portion scheduled as a wiring is protected. In this case, the photoresist pattern 34 is formed to have a size that protects a larger area than a predetermined portion of the tungsten layer 32 by wiring, for example, 0.6 μm, and the size thereof is formed in consideration of process conditions in a subsequent etching process. do. (See Figure 3 (A))

Next, the tungsten layer 32 exposed by the photosensitive film pattern 34 is isotropically etched under a predetermined dry etching condition to form a tungsten layer 32 wiring. At this time, the photoresist pattern 34 is also horizontally etched at the same time, thereby forming a tungsten layer 32 wire having a width smaller than a portion protected by the photoresist pattern 34, for example, about 0.3 to 0.4 μm. At this time, the photosensitive film pattern 34 has a width of about a predetermined partial immersion even after the tungsten layer 32 wiring is finally formed. This is because when the photoresist pattern 34 is removed by horizontal etching during the etching process, the upper width of the tungsten layer 32 wiring is formed so small that electrical characteristics are degraded. (Fig. 3 (B) Deduction)

Thereafter, the etched and etched photoresist pattern 34 is removed to complete the tungsten layer 34 wiring.

The dry etching method includes magnetically enhanced reactive ion etching (hereinafter referred to as MERIE), flat plasma etching, and the like. Seed. Various methods are used to horizontally etch the photoresist pattern, such as eggs (electon cycrotron resonance), and to isotropically etch the tungsten layer.

Let's look at the etching method in more detail with reference to the experimental results of the present inventors.

First, using a dry etching equipment of the MERIE method, etching with SF ₆ / C1 ₂ plasma, and a small amount of Ar, N ₂ or HBr participate in order to control the shape according to the etching degree of the tungsten layer wiring. The gas flow rate ratio of SF ₆ : C 1 is about 1.5 to 2.5: 1, the chamber internal pressure is 300 to 500 mTorr, the RF power is 300 to 450 watt, the magnetic field is maintained at 30 to 60 gauss, and the total gas flow rate is 120 to Dry etching is performed under the condition of 160 sccm, and when the Ar, N ₂ or HBr is added, the total flow rate is about 5 to 25 sccm. When the line width of the photoresist pattern is 0.6 µm, tungsten wiring having 0.2 to 0.3 µm line width Can be formed.

In addition, although the tungsten wiring is exemplified above, the idea of the present invention may be applied to the formation of metal layers other than tungsten, for example, aluminum, titanium, and gold.

As described above, in the method of manufacturing a semiconductor device according to the present invention, after forming a photoresist pattern having a width larger than that of the wiring to be formed in the metal wiring formation process, the metal wiring isotropically etched and the photoresist pattern is horizontally The etching was performed to form a fine metal wiring having a width smaller than that of the first photoresist pattern. Therefore, even with a conventional i-line stepper, a fine pattern of 0.4 μm or less can be easily formed without an additional process, and thus, the semiconductor device can be highly integrated.

Claims (4)

A method of manufacturing a semiconductor device in which a metal wiring is formed by performing an etching process using a photosensitive film pattern as a mask, the method comprising: forming a photosensitive film pattern having a wider width than a predetermined portion of the wiring on a metal layer formed on a predetermined substrate; And isotropically etching the metal layer using the photoresist pattern as a mask, and dry etching the photoresist pattern to form a metal wiring, thereby forming metal wirings. The method of claim 1, wherein the metal layer is formed of tungsten or aluminum. The method of claim 1, wherein the dry etching method comprises self-induced reactive ion etching, plate plasma etching, and the like. Seed. A method for manufacturing metal wiring in a semiconductor device, characterized in that the method is performed by one method arbitrarily selected from the group consisting of egg (electon cycrotron resonance) etching. The method of claim 1, wherein the dry etching method is etched using SF ₆ / C1 ₂ plasma, and a small amount of Ar, N2 or HBr is added to adjust the shape according to the etching degree of the metal wire. A metal wiring manufacturing method of a semiconductor device.