JPS63224231A - Etching device - Google Patents

Abstract

PURPOSE:To make possible a uniform etching by arranging magnets outward of a chamber. CONSTITUTION:16 10-mm diameter and 25-mm long samarium-cobalt magnets 21 are arranged in 3 stages at a place near a cathode 13 in the air on the outside of a chamber 11 and they are formed into a three-stage constitution to generate a magnetic flux density. Ar gas is introduced, an RF power source 15 is turned-ON to generate plasma in the chamber 11 and when alumina covering a first layer wiring on a wafer 4 is etched with Ar ions, an etching rate of 150-250 Angstrom /min is obtained when expressed in terms of SiO2 equivalent and an etching rate, which is at least 3 times higher compared to the conventional example wherein there is no magnet, is obtained. According to that, the amount of power consumption of the power source 15 is decreased and the temperature rise of the wafer is also reduced. Moreover, the strength and position of the magnets 21 are controlled. Thereby, the distribution of a uniform etching rate can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In a high-frequency etching apparatus, magnets having a strength of at least a predetermined value are arranged around a chamber to improve the etching rate and distribution, and the position of the magnet is made variable.

[Industrial Field of Application] The present invention relates to semiconductor manufacturing equipment, and more particularly to an improvement in a high frequency discharge etching equipment in which a magnet with a large magnetic force is fixedly or movably arranged to improve the etching rate and etching distribution.

[Conventional technology]

In circuits of semiconductor integrated circuit devices, there has been a recent trend toward manufacturing multilayer semiconductor devices in order to achieve higher circuit integration. For example, a first layer wiring is formed of aluminum (AN) on a semiconductor substrate, a glabella insulating film is formed on the first layer wiring, and a contact hole is formed at a predetermined position of the glabella insulating film. Techniques have been developed in which a window is opened, and then, when the second layer wiring is formed, the contact hole is filled with a wiring material such as 8β to make contact between the first layer and the second H wiring.

[Problem that the invention seeks to solve]

In forming the multilayer wiring described above, the surface of the first layer i wiring is oxidized and covered with a thin film of alumina. This alumina causes poor contact and increased resistance, so we etched it away and made it pure A7! Then, a second layer wiring is formed to make contact between the i wiring in the first layer and the second layer to prevent connection failure and increase in resistance at the contact portion.

Such etching is referred to as multilayer pretreatment etching.

The multilayer pretreatment etching described above is carried out using the apparatus shown in FIG. 4, in which 11 is a chamber, 12 is
is an anode, 13 is a cathode, 14 is a sample (for example, a wafer), 15 is a high frequency (R1 power supply), 16 is a shield, and the first eyebrow A/wiring described above is formed on the sea urchin fly 4, and A multilayer pre-etching process is performed using argon (Ar) in the chamber II.
) A gas is introduced into the chamber, a plasma is generated in the chamber using a power supply 15, and a first layer i is formed on the wafer 14 using meter ions.
Etch the surface of the wiring.

In conventional etching using such equipment, the etching rate is extremely slow. Since it is difficult to directly measure the etching rate of alumina itself, the etching rate of alumina is usually expressed in terms of the etching rate of silicon dioxide (5iO2). /min. To remove alumina on the β wiring to the first layer in the multilayer wiring formation process, 150 to 20
I have to etch 0 people. In that case, 1
It takes about 4 minutes to process one wafer, resulting in poor throughput, a heavy load on the RF power source, and an increase in wafer temperature. In particular, when the temperature of the wafer increases, the impurity diffusion region already formed within the wafer expands, which poses a problem.

The present invention was created in view of the above points, and an object of the present invention is to provide an etching apparatus capable of solving the above-mentioned conventional problems. The apparatus of the present invention is not an etching apparatus for pattern formation, but relates to the above-mentioned etching apparatus for multilayer pretreatment.

[Means for solving problems]

FIG. 1 is a diagram of an embodiment of the present invention, and in the figure, 21 is a magnet.

In the present invention, the magnet 2 is placed outside the chamber 11.
Place 1. The magnetic force of the magnet 21 is 300 Gauss at a distance of 30 mm 1 il from the magnet, and 100 Gauss at the center of the chamber 11.
300-500 Gauss O on the surface of the anode 12
) so that the magnetic flux density can be obtained. The magnet 21 is fixed at the position shown in the figure, or is constantly reciprocated within the range indicated by the arrow in the figure.

[Effect]

The reason why the etching rate is slow in conventional equipment is thought to be that in the absence of a magnet, electrons are floating irregularly, and fewer ions collide with the wafer. In the above-mentioned apparatus, electrons in the chamber are confined within the magnetic lines of force formed by the magnet 21, increasing the ionization efficiency of Ar, thereby increasing the number of ions that collide with the wafer and contribute to etching, thereby reducing the etching rate. It is understood that it will be faster.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the apparatus of FIG. 1, in the atmosphere outside chamber 11, close to cathode 13, a diameter of 10 mm is placed.

Sixteen samarium cobalt (SmCo) magnets each having a length of 25 mm were arranged in three stages to form a three-stage configuration to generate the magnetic flux density described above.

Introduce the meter gas, turn on the RF power supply 15, and turn on the chamber 1.
When plasma was generated in the etching chamber 1 and alumina covering the first layer wiring (not shown) on the wafer 14 was etched with Ar ions, an etching rate of 150 to 250 people/min was obtained in terms of 5i02, compared to the conventional example without a magnet. An etching rate that is at least three times higher than that obtained was obtained, and the power consumption of the weighing source 15 was correspondingly reduced, and the temperature rise of the wafer was also reduced.

The strength of the magnet 21 is 30m from one magnet.
It is assumed that a magnetic flux density of about 300 Gauss can be obtained at a distance of m, and in one embodiment, 16 of the above-mentioned
SmCo magnets 21 are arranged at equal intervals around the chamber 11 as shown in FIG. 2, and are arranged in three stages, with a total of 48 magnets, and the magnets are located 251 points away from the wafer surface. , 15 per minute
We were able to secure an etching rate of 0 ± 5%. Note that FIG. 2 is a view of the chamber 11 from the cathode side, and only the chamber and magnet are shown for the sake of simplicity.

An experiment on the distribution of the etching rate revealed that when the magnet 21 is close to the cathode 13, the etching rate on the wafer becomes higher at the periphery than at the center of the wafer, as shown in Figure 3 (al). On the other hand, when the magnet 21 is close to the anode 12 side, the etching rate is high at the center of the wafer (lower at the periphery and convex upward), as shown in FIG. In FIGS. 3A and 3B, the horizontal axis represents the position on the wafer, and the vertical axis represents the etching rate.

Therefore, in another embodiment of the present invention, the magnet 21 is constantly reciprocated within the 50 mm range surrounded by the arrow in FIG. I made it.

〔Effect of the invention〕

As described above, in the etching apparatus using the magnet of the present invention, the etching rate is improved by at least three times that of the conventional example, and by moving the magnet, a uniform etching rate distribution can be obtained.
We were able to improve the throughput of forming a multilayer wiring structure, reduce the power consumption of the power supply, and reduce the temperature rise of the wafer. It should be noted that, although the above-mentioned multilayer wiring is formed by etching alumina on the A1 surface, the scope of the present invention is not limited to that case.

[Brief explanation of the drawing]

Figure 1 is a diagram of an embodiment of the present invention, Figure 2 is a diagram showing the arrangement of magnets, Figure 3 fa) and (bl are diagrams showing the distribution of etching rates, and Figure 4 is a diagram of a conventional example. In Figures 1 and 3, 11 is a chamber, 12 is an anode, 13 is a cathode, 14 is a wafer, 15 is an RF power source, 16 is a shield, and 21 is a magnet. Agent: Patent attorney Akifuku Kukimoto Person Patent Attorney Yoshiyoshi Osuga 19th January # Directions B4 Figure 1 Mafukizuto 4 t1 Figure 2 Goshi γ U' Shift Rehieteke 7' Rate 1 Egg t Newa 1 Figure 3 Condition 7fi11 old figure 4

Claims (2)

[Claims] (1) A chamber (11) in which a sample (14) is placed.
), an anode (12) connected to a high frequency power source (15)
In a high-frequency discharge device consisting of a cathode placed opposite to an anode, a magnet (21) is placed on the cathode (13) side in the atmosphere outside the chamber (11) to increase plasma efficiency within the chamber. A semiconductor manufacturing device characterized by: (2) The device according to claim 1, wherein the magnet (21) is configured to be capable of reciprocating movement toward and away from the cathode within a predetermined range.