KR20040001867A - Method for fabricating sem1conductor device with improved protection of attack by plasma - Google Patents

Abstract

PURPOSE: A method for manufacturing a semiconductor device is provided to be capable of minimizing attacks of a conductive pattern in metal contact etching. CONSTITUTION: A conductive pattern(22) for forming a metal contact is selectively etched to form an opening part(25) by using plasma pulse. At this time, the plasma pulse has a desired duty rate for generating anion in order to neutralize attacks of cation. Preferably, a plate electrode of a capacitor is used as the conductive pattern(22). The duty rate is 60-70 percents. Also, the plasma etching gas contains CF4 and Ar.

Description

Method for manufacturing semiconductor device that can prevent plasma attack {METHOD FOR FABRICATING SEM1CONDUCTOR DEVICE WITH IMPROVED PROTECTION OF ATTACK BY PLASMA}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to manufacturing a semiconductor device suitable for preventing a lateral attack of a plate electrode occurring in a metal-1 contact (hereinafter referred to as M1C). It is about a method.

When M1C is etched at the same time with the bit line or the substrate for the metal contact of the plate electrode, the plate has a thickness of more than five times thinner than that of the bit line or the substrate. After etching, the metal contact is performed by filling the metal between the holes.

1 shows a schematic cross-sectional view of a metal contact etching process and a cleaning process immediately following the prior art.

Referring to FIG. 1, a first insulating layer 11 is formed on a substrate 10 having various elements for forming a semiconductor device, and a plate electrode 12 made of polysilicon or the like is formed thereon. The second insulating layer 13 and the photoresist pattern 14 are formed on the plate electrode 12.

The open portion 15 formed as the etch stops in the first insulating layer 11 is formed by penetrating the second insulating layer 13 and the plate electrode 12 using the photoresist pattern 14 as an etching mask by M1C etching. It is.

In the conventional M1C etching process, the mixed gas of C ₄ F ₈ / CO / Ar / O ₂ is used as the stock angle gas by using an MERIE (Magnetically Enhancement Reactive Ion Etching) etching apparatus.

On the other hand, here, due to the etching characteristics of the equipment itself, the cation causes a lateral attack on the side wall of the plate electrode 12, which shows the attack of the plate electrode 12, such as '16', which appears mainly after cleaning. Therefore, in order to reduce the attack of the plate electrode 12 by a large number of cations as described above in actual process applications, the process recipe (Recipe) has been modified in various forms, but in the current technical stage, such as the ratio of selectivity, the tactical One problem cannot be solved.

In addition, since the size and thickness of the pattern may be reduced as the degree of integration of the device may be improved, performance and reliability of the device may be degraded by physical and electrical damage due to ion bombardment when using continuous waves. In particular, the capacitor of the FeRAM device is easily deteriorated in dielectric properties even by small damage. Continuous wave, which is commonly used, has almost all cations, and the distribution of negative ions in the plasma is very small. Therefore, it is necessary to use a technique to prevent sidewall attack by the proper distribution of positive and negative ions. It is true.

The present invention has been proposed to solve the above problems of the prior art, and an object of the present invention is to provide a method of manufacturing a semiconductor device suitable for minimizing the attack of the conductive film pattern, such as plate electrodes during metal contact etching.

1 is a schematic process cross-sectional view immediately after the metal contact etching process and cleaning according to the prior art.

Figure 2 is a schematic process cross-sectional view immediately after the metal contact etching process and cleaning in accordance with the present invention.

Explanation of symbols on the main parts of the drawings

20 substrate 21 first insulating film

22 plate electrode 23 second insulating film

24 photoresist pattern 25 open part

In order to achieve the above object, the present invention, in the etching process for forming a metal contact penetrating through the conductive film pattern, anion for neutralizing the attack by the accumulated cations on the surface of the conductive film pattern etched by plasma generation A semiconductor device manufacturing method is characterized by etching using a plasma pulse to have a duty ratio for generating.

The present invention increases the anion distribution in the plasma by controlling the duty ratio, that is, the time for which the pulse is applied to the entire plasma generation time using the plasma pulse during etching for the metal contact, thereby increasing the lateral attack of the plate electrode or the like. To prevent plasma damage.

Hereinafter, the present invention will be described in detail with reference to FIG. 2 attached to the most preferred embodiment of the present invention in order that the present invention may be easily implemented by those skilled in the art.

The present invention is a source of etching equipment such as inductive coupled plasma (ICP), electrified cyclotron resonance (ECR), or transformer coupled plasma (TCP) during an etching process for a metal contact to construct a pulsed plasma matching network. A pulse controller of 10 Hz is attached to the power supply to perform etching using plasma pulses. In addition, the source and bias frequencies use 13.56 MHz.

Figure 2 shows a schematic cross-sectional view of the metal contact etching process and immediately after cleaning in accordance with the present invention.

Referring to FIG. 2, a first insulating film 21 is formed on a substrate 20 on which various elements for forming a semiconductor device are formed, and a plate electrode 22 made of polysilicon or the like is formed thereon. The second insulating layer 23 and the photoresist pattern 24 are formed on the plate electrode 22.

The open portion 25 formed as the etch stops in the first insulating layer 21 through the second insulating layer 23 and the plate electrode 22 through the photoresist pattern 24 as an etching mask by M1C etching is formed. It is.

In the illustrated M1C etching process of the present invention, the mixture gas of CF ₄ / Ar was used as the stock corner gas by using an ICP etching apparatus.

In the present invention, it has a duty ratio for generating anion that neutralizes the attack by the accumulated cations on the surface of the conductive film pattern, such as the plate electrode 22 etched by the plasma generation, that is, the surface exposed to the plasma.

In this case, the duty ratio is preferably about 70% as the pulse is applied to the entire plasma generation time, and is maintained in the range of about 60% to 70%, and the etching by the plasma is about 50% of the duty ratio. Shall be.

This is to improve anion generation and will be described in detail below.

In general, a plasma that does not use pulses is called a continuous wave mode, and in these plasmas, electrons are generally very active and have a small adhesion effect of neutral atoms, so that anion formation is not properly performed. This causes positive charges to accumulate on the sidewalls of the photoresist and the oxide film-based insulating film, and thus the accumulated charge causes an attack on the conductive film pattern of the plate electrode or the like.

To solve this problem, for example, when plasma pulse 10㎑ is applied to CF ₄ / Ar mixed gas with 70% duty ratio in ICP type etching equipment, anions such as F-, CF ₃ -and up to 10 ⁷ arb It is possible to prevent the attack of the plate electrode by neutralizing the cations accumulated on the sidewalls as described above up to .units, that is, from 10 ⁵ arb.units to 10 ⁷ arb.units.

Here, the density of negative ions increases and the decrease of positive ions is relatively high in the F or CF ₃ group as the high-energy electrons are cooled during the afterglow time during the plasma pulse formation having a cycle of several micrometers to several tens of micrometers. This is because an attachment reaction occurs and an anion is formed and the duty ratio of the highest density is about 70%.

Here, the source power and the bias power will vary depending on the characteristics and thickness of the material to be etched, and thus, the description of the source power and the bias power are not limited thereto. Various applications are possible for etching conductive film pads.

In the present invention described above, the plasma electrode is used in the etching process penetrating the plate electrode, and the duty ratio is maintained at about 70% to maximize the anion generation density, thereby neutralizing the accumulated cations on the sidewall to be etched. It was found through the examples that the lateral attack of the can be minimized.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

According to the present invention as described above, by minimizing the attack by the cation of the conductive film pattern according to the plasma etching, it can be expected that the excellent effect that can ultimately improve the characteristic yield of the semiconductor device.

Claims (9)

In the etching process for forming a metal contact penetrating the conductive film pattern, And etching by using a plasma pulse to have a duty ratio for generating anions that neutralize the attack by the accumulated cations on the surface of the conductive film pattern etched by plasma generation. The method of claim 1, The conductive film pattern is a semiconductor device manufacturing method, characterized in that consisting of polysilicon. The method of claim 2, The conductive film pattern is a semiconductor device manufacturing method, characterized in that the plate electrode of the capacitor. The method of claim 1, And the duty ratio is 60% to 70%. The method of claim 1, The gas at the time of plasma etching, the manufacturing method of a semiconductor device comprising CF ₄ / Ar. The method of claim 5, The anion is a semiconductor device manufacturing method characterized in that F- or CF _3- . The method of claim 6, The method of manufacturing a semiconductor device, characterized in that the density of the anion is 10 ⁵ arb to 10 ⁷ arb. The method of claim 1, Wherein the plasma pulse is 10 kHz and the frequency is 13.56 MHz. The method of claim 1, A method of fabricating a semiconductor device comprising using an inductive coupled plasma (ICP), an electro cyclotron resonance (ECR), or a transformer coupled plasma (TCP) etching equipment during the etching process.