JPH07221079A - Plasma apparatus and dry etching method using it - Google Patents

Abstract

PURPOSE:To obtain a plasma apparatus in which a high-accuracy minute working operation can be performed by a method wherein at least a part of the inner wall of a high-vacuum container which generates a high-density plasma at a specific ion density inside the container is constituted of an Al-based member and the Al-based member can be heated. CONSTITUTION:At least one plasma generation means which generates a high- density plasma at an ion density of 10<11>/cm<3> or higher inside a high-vacuum container 7 is provided. The high-density plasma which is generated is at least one out of a helicon wave plasma and an inductive-coupling plasma. Then, for example, the ceiling plate 6 of the process chamber 7 for a helicon wave plasma apparatus is constituted of an Al plate, and the Al plate can be heated. The ceiling plate 6 comes into contact with the helicon wave plasma PH which has been extracted into the process chamber 7, and it is used as the supply source of Al. A heater 4 promotes the progress of a chemical reaction on the surface of the ceiling plate 6 in a dry-etching process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma apparatus applied to the manufacture of semiconductor devices and a dry etching method using the same, and particularly to an aluminum (Al) -based material film containing copper (Cu) with an ion density of 10 ¹¹ / cm ³
The present invention relates to an apparatus and a method capable of preventing the generation of etching residues due to Cu when etching is performed using so-called high-density plasma.

[0002]

2. Description of the Related Art As a wiring material film for a semiconductor device, Al is used.
The base material film is most widely used. This Al-based material film is required to achieve more excellent electromigration (EM) resistance and stress migration (SM) resistance than ever with the adoption of a multilayer wiring structure in a commercial chip. Against this background,
It is becoming essential to add Cu to the Al-based material film. The addition of Cu was initially 0.
It was done at a small level like adding 5%,
In recent years, with respect to the wiring film used on the upper layer side of the wiring film for substrate contact, Al-2% Cu or Al-
It is also considered to be added in a larger amount level such as 4% Cu.

Dry etching of Al-based wiring films is generally performed using chlorine-based gas. For example, BCl ₃ / Cl disclosed in JP-B-59-22374.
_A mixed gas of ₂ is a typical example of such a chlorine-based gas. The chemical species that contributes as the main etching species in the etching of the Al-based wiring layer is Cl ^* , which promotes a spontaneous and extremely rapid etching reaction. However, since the etching proceeds isotropically only with Cl ^* , the ion assist mechanism is usually activated under the condition that the incident ion energy is supplied to some extent, and high anisotropy is achieved.

With respect to this dry etching, the requirements for low gas pressure, high plasma density, low magnetic field in the vicinity of the substrate, etc. have been raised to a higher level than in the past with the advancement of finer design rules of semiconductor devices. It is required to be satisfied. Under such circumstances, several kinds of new high-density plasma devices have been proposed one after another in recent years. JP-A-3-
The helicon wave plasma device described in Japanese Patent No. 68773 is one of the most promising devices among such devices. The plasma generation mechanism applies a magnetic field to a cylindrical chamber and further applies a high frequency to a loop antenna wound around the chamber to generate a helicon wave in the chamber, and the helicon wave is used to reduce the Landau attenuation. By transporting energy through the process, electrons are accelerated and the accelerated electrons collide with gas molecules. For helicon wave plasma, approximately 10 ¹¹ to 10 ¹³
High ion densities of / cm ³ can be achieved.

Monthly Semiconductor World 19
October 1993 p. 68 to 75 in the (press journal published by), inductively coupled plasma (ICP: I nducti
vely C oupled P lasma) I was using the
A CP etching device is described. This is because a high frequency power is supplied to a non-resonant multi-turn antenna wound around a quartz cylinder, which is a plasma generation chamber, and electrons are rotated according to a magnetic field formed inside the antenna. And a gas molecule with a high probability of collision. According to ICP, an ion density of approximately 10 ¹¹ to 10 ¹² / cm ³ can be achieved.

[0006]

By the way, in dry etching of an Al-based wiring film, the generation of a large amount of residue has become a serious problem as the amount of Cu added increases. This problem will be described with reference to FIGS. 2 and 10. As an etching sample, as shown in FIG. 2, an Al-based wiring film 37 is formed on the SiO ₂ interlayer insulating film 31, and a resist mask 38 patterned into a predetermined shape is further formed thereon. Consider a wafer.
Here, the Al-based wiring film 37 goes from the lower layer side to the upper layer side, and the barrier metal 34 composed of the Ti film 32 and the TiN film 33, the Al-4% Cu film 35, the TiON antireflection film 36.
Are sequentially laminated.

The state of the wafer after etching the Al-based wiring film 37 using a conventional general chlorine-based gas
As shown in FIG. In the figure, the anisotropically processed material film is represented by adding the subscript a to the original code. By this etching, a wiring pattern having an anisotropic shape is formed in the portion shielded by the resist mask 38, but a large amount of needle-like residue 40 is also generated in the portion not shielded. This is because Cu contained in the Al-4% Cu film 35 reacts with Cl ^{* in} plasma to generate copper chloride having a low vapor pressure, which functions as a fine etching mask called a micro mask 39. As a result, this micro
This is because the Al-4% Cu film 35 and the barrier metal 34 remain in the region shielded by the mask 39.

Therefore, in order to remove the residue 40, a method of increasing the incident ion energy during etching to enhance the ion sputtering effect is usually adopted. However, in the situation where the amount of the residue 40 generated increases with the increase of the amount of Cu added, the desired removal effect has not been achieved. This basically does not change even if a device such as a helicon wave plasma device or an ICP device that can obtain a high ion current density is used.

Alternatively, as a method for removing the residue 40, for example, the 37th Joint Lecture on Applied Physics (1
990 Spring Annual Meeting) Proceedings, p. 456, Lecture No. 28a-ZF-1 reports a method of chemically removing the residue. Specifically, overetching is performed under isotropic conditions in which radical reaction is the main component, so that the needle-like residue 40 is also eroded from the lateral direction and is removed. However, although this method is effective for removing the residue 40, the micro mask 3
Since 9 itself cannot be decomposed and removed, there is a great possibility that the micro mask 39 itself will become a particle contamination source.

Particularly, in the helicon wave plasma apparatus, there is a great possibility that it is difficult to perform overetching under such isotropic conditions. This is because in a low-pressure and high-density plasma such as helicon wave plasma, the electron temperature is extremely high and the dissociation of gas molecules proceeds too much.
This is because the ions are excessively generated, but the radical generation amount tends to be insufficient.

Also, the 1992 Dry Process Symposium Abstracts p. 59 to 63, a method for volatilizing and removing copper in the form of a chloroaluminum complex salt is described.
In this method, a secondary electrode coated with an alumina target is provided on the wall surface of a static magnetron triode RIE apparatus, and copper chloride generated in the process of etching an Al-Cu alloy film using a chlorine-based gas 12 with aluminum chloride supplied from the target
By reacting on a substrate heated to about 0 ° C,
It produces chloroaluminum copper.

However, since the above heating temperature is close to the upper limit of the heat resistant temperature of the resist mask which is usually used, it is desirable to avoid heating the substrate as much as possible. As described above, according to the conventional technique, it is difficult to suppress the generation of residues and particles due to Cu when dry-etching the Al-based wiring film containing Cu. Therefore, an object of the present invention is to solve these problems and to provide a plasma apparatus capable of performing highly precise microfabrication and a dry etching method using the same.

[0013]

The present invention is proposed to achieve the above objects. That is, the plasma apparatus according to the present invention comprises a high vacuum container for containing a substrate and at least one plasma generating means for generating high density plasma having an ion density of 10 ¹¹ / cm ³ or more in the high vacuum container. At least a part of an inner wall surface of the high vacuum container is made of an Al-based member, and
A heating means for heating the system member is provided.

The Al-based member can typically be made of pure Al or alumina (AlO _x ). In addition, as the form, any of thin films, thin plates, targets for sputtering, and the like can be used.

The high-density plasma generated in the present invention is at least one of helicon wave plasma and ICP. The helicon wave plasma generation has a plasma generation chamber that is circulated by the first high-frequency antenna and the magnetic field generation means and is connected to the high vacuum container, and supplies the helicon wave plasma to the high vacuum container. It can be generated using any means.

The ICP has a non-conductive member that constitutes a part of the high vacuum container in the axial direction, and a second high-frequency antenna wound around the outer peripheral side of the non-conductive member. It can be produced using an ICP producing means for producing ICP in a vacuum container.

Of course, if both the helicon wave plasma generating means and the ICP generating means are provided together, both plasmas can be generated. At this time, it is extremely effective that the second high frequency antenna for exciting the ICP is symmetrically wound around the axial direction of the magnetic field generated by the magnetic field generating means for generating the helicon wave. This is because the magnetic field generated by the magnetic field generation means and the axial direction of the magnetic field generated by the second high frequency antenna are made to coincide with each other, whereby plasma is efficiently transported in the high vacuum container, and the second magnetic field is generated. This is because the plasma confinement effect of the magnetic field generated by the high frequency antenna can suppress the consumption of chemical species by the inner wall surface of the high vacuum container.

A high frequency for plasma excitation is applied to both the first high frequency antenna and the second high frequency antenna, but interference is prevented when the frequencies applied to both antennas are the same. Therefore, it is particularly effective to perform control to shift the phases from each other. This control can be easily performed using the phase shifter circuit.

By the way, the Al-based member may constitute any region of the inner wall surface of the high-vacuum container as long as it can sufficiently contact the high-density plasma.
It is expedient to construct a region facing the substrate.
In particular, when a part of the high-vacuum container in the axial direction is made of a non-conductive member in order to generate the ICP, the Al-based member, which is highly practical, is disposed at a position substantially facing the substrate.
Further, even when the ICP generating means is not used, when it is necessary to secure a region functioning as a counter earth electrode for the substrate bias, the conductive Al-based member also has a function as the electrode. Therefore, it is necessary to provide it on the surface facing the substrate.

The above plasma apparatus is suitable for use in dry etching a Cu-containing Al-based material film on a substrate housed in the high vacuum container. Etching at this time
A conventionally known chlorine-based gas is used as the gas. Also,
As long as the Cu-containing Al-based material film is an Al-based material film to which Cu is added for the purpose of improving EM resistance or SM resistance, the Cu addition amount does not matter, and other addition such as Si It does not matter whether the element is present or not.

[0021]

The point of the present invention is that a heated Al-based member is provided on at least a part of the inner wall surface of the high vacuum container of the plasma device capable of generating at least one of helicon wave plasma and ICP. This Al-based member is sputtered by the ions abundantly contained in the high-density plasma as described above, and the Al-based chemical species can be efficiently supplied into the high vacuum container.

In particular, when helicon wave plasma and ICP are used together, the latter can compensate for the lack of radicals in the former, and thereby the ion / radical production ratio in the plasma can be controlled to provide an ion assist mechanism. You can work smoothly. This also improves the etching rate.

Further, by disposing the Al-based member in at least a region facing the substrate on the inner wall surface of the high vacuum container, the design and manufacturing of the plasma device can be simplified.
Further, in many cases, a substrate bias is also used during dry etching using such a plasma device, and therefore, by disposing an Al-based member on the substrate facing surface, this can be used as a large-area DC ground electrode for plasma. it can. As a result, it is possible to minimize spatter on the inner wall of the high vacuum container and to continue stable discharge over a wide area.

When the Cu-containing Al-based material film is etched using chlorine-based gas in the above high vacuum container, a large amount of aluminum chloride is produced on the surface of the Al-based member exposed to the high-density chlorine-based chemical species. . This aluminum chloride reacts with copper chloride released into the plasma as an etching reaction product under heating conditions to change to Al ₂ CuCl ₈ ,
It is volatilized and removed in the form of this complex salt. Therefore, there is no risk of residues being generated as in conventional etching. Moreover,
The present invention does not heat the wafer, unlike the prior art which also utilizes copper chloroaluminum, so there is no problem in using the resist mask.

[0025]

EXAMPLES Specific examples of the present invention will be described below.

Example 1 In this example, a helicon wave plasma to which the present invention is applied
A configuration example of the etching apparatus will be described. In Figure 1,
The conceptual structure of this etching apparatus is shown. This device
The top plate of the process chamber, which is the high vacuum container of the helicon wave plasma etching device, is made of an Al plate,
This is heated from the back side by a heater.

First of all, the helicon wave plasma generation unit has a bell jar 1 made of a non-conductive material for generating the helicon wave plasma P _H therein, and orbits the bell jar 1 2
A loop antenna 2 for coupling RF power to plasma, which is provided so as to circulate around the chamber 1, generates a magnetic field along the axial direction of the chamber 1, and mainly generates a helicon wave. The inner peripheral side solenoid coil 3a that contributes to the propagation and the outer peripheral side solenoid coil 3b that mainly contributes to the transport of the helicon wave plasma P _H are the main constituent elements.

Here, the constituent material of the bell jar 1 is quartz. RF power is applied to the loop antenna 2 from an RF power source 15 for plasma excitation through a first matching network (M / N) 14 for impedance matching, and currents in opposite rotating directions are applied to the upper and lower two loops. Flows. Here, the frequency of the plasma excitation RF power supply 15 is 13.56 MHz. The distance between both loops is optimized according to the desired wave number of the helicon wave.

The bell jar 1 is connected to the process chamber 7, and enters into the process chamber 7 along the divergent magnetic field formed by the inner solenoid coil 3a and the outer solenoid coil 3b. _H
Is designed to pull out. Process chamber 7
The side wall surface and the bottom surface of are made of a conductive material such as stainless steel. The interior thereof is evacuated to high vacuum in the direction of arrow A through an exhaust hole 8 by an exhaust system (not shown), and the gas required for dry etching is supplied in the direction of arrow B from a gas supply pipe 5 opened in the top plate 6. Further, it is connected to the load lock chamber (not shown) through the gate valve 23 on the side wall surface thereof.

Further, a conductive substrate stage 9 electrically insulated from the wall surface of the process chamber 7 is housed inside the process chamber 7, and a wafer W, for example, serving as a substrate to be processed is held on the conductive substrate stage 9. It is designed to perform etching. On the substrate stage 9 in order to maintain the wafer W in the process to a desired temperature, supplied with refrigerant from a not shown chiller, which arrows C _1, C ₂
A cooling pipe 10 for circulating in the direction is inserted.

The substrate stage 9 has a wafer W for controlling the energy of ions entering from the plasma.
RF power source 12 for applying a bias to the substrate
Are connected via a second matching network (M / N) 11. Here, RF for bias application
The frequency of the power supply 12 was 13.56 MHz. further,
A magnet 13 capable of generating a multi-cusp magnetic field as an auxiliary magnetic field generating means is arranged outside the process chamber 7 in order to converge the divergent magnetic field in the vicinity of the substrate stage 9.

The structure up to this point is similar to that of the conventional helicon wave plasma etching apparatus, but the feature of this dragee etching apparatus is the top plate 6 and the heater for heating it from the back side. It is 4. Above top plate 6
Acts as a supply source of Al by coming into contact with the helicon wave plasma P _H drawn into the process chamber 7. Further, since it is in a geometrically parallel positional relationship with the substrate stage 9 to which a substrate bias is applied, it also functions as a DC ground electrode for plasma, and the plasma chemical species generated by the inner wall surface of the process chamber 7 Consumption is suppressed and it contributes to continuous stable discharge. The heater 4 also contributes to promoting the progress of chemical reactions on the surface of the top plate 6 during the dry etching process.

Example 2 In this example, the etching apparatus described in Example 1 was used to etch an Al-based wiring film containing an Al-4% Cu film. This process will be described with reference to FIGS. FIG. 2 shows a cross section of the main part of a wafer used as an etching sample in this example. This wafer is S
An Al-based wiring film 37 is formed on the iO _x interlayer insulating film 31, and a resist mask 38 is further formed thereon in a predetermined pattern. Here, the Al
The system wiring film 37 is made of Ti-based barrier metal 34, Al-4.
% Cu film 35 and TiON antireflection film 36 are sequentially laminated, and the Ti-based barrier metal 3 is also used.
4 is, for example, a Ti film 32 and a TiN film 3 in order from the lower layer side.
3 and 3 are laminated.

The resist mask 38 is, for example, a KrF excimer film made of a chemically amplified resist material.
The pattern width is, for example, 0.25 μm through laser lithography.

This wafer was set on the substrate stage 9 of the above-mentioned etching apparatus. The top plate 6 was heated to about 250 ° C. using the heater 4. In this state, first TiO
The N antireflection film 36 and the Al-4% Cu film 35 were used as an example and etched under the following conditions. BCl ₃ flow rate 60 SCCM Cl ₂ flow rate 90 SCCM Gas pressure 0.13 Pa Source power (P _H excitation) 2000 W (13.5
6 MHz) RF bias power 150 W (13.5
6 MHz) Substrate stage temperature 20 ° C (water cooling)

In this process, the helicon wave plasma P _H is contacted with a large amount of chlorine-based species,
A large amount of AlCl _x was supplied from the heated top plate 6.
CuCl _x having a low vapor pressure generated by the etching of the Al-4% Cu film 35 reacted with this AlCl _x to be changed to chloroaluminum copper having a high vapor pressure, and was quickly removed. Therefore, by this etching, as shown in FIG. 3, the Al-based wiring pattern 37a having a good anisotropic shape could be obtained. Among the patterns of each material film obtained after etching, the anisotropic ( a ni
Those having a sotropic shape are represented by adding a subscript a to the reference numeral of the original material film (the same applies hereinafter). No needle-like residue or particle contamination in the process chamber 7 as in the conventional case occurred.

Embodiment 3 In this embodiment, an ICP generator is added to the helicon wave plasma etching apparatus described in Embodiment 1 so that a helicon wave plasma and an ICP can be simultaneously generated. The device will be described. FIG. 4 shows a conceptual configuration of this etching apparatus.
This apparatus is provided with a helicon wave plasma generation unit in the top region of a process chamber, which is a high-vacuum container, and an ICP generation unit in the region downstream of the process chamber. Has a configuration adapted to supply the source power via.

In the ICP generating section, a cylinder 16 made of a non-conductive material occupies a part of the conductive chamber wall of the process chamber 7 in the axial direction, that is, a part of a cylindrical side wall surface, and its outer periphery. A multi-turn antenna 17 wound on the side is included. Here, the cylinder 1
The constituent material of No. 6 was quartz. The multi-turn antenna 17 is connected to the plasma excitation RF power source 15 via a third matching network 18, a phase shifter 19, and a switch 21. The number of turns of the multi-turn antenna 17 is optimized according to conditions such as the diameter of the cylinder 16 and the applied RF frequency.

On the other hand, since the switch 21 is provided, the RF power source 15 for plasma excitation and the first matching
A switch 20 is also provided between the switch and the network 14 to control the high frequency application to the loop antenna 2 for exciting the helicon wave plasma P _H. The phase shifter 19 shifts the phases of the high frequencies applied to the loop antenna 2 and the multi-turn antenna 17 by ½ cycle to prevent the interference between the high frequencies and generate stable plasma discharge. It will be realized.

The bell jar 1, the cylinder 16, the multi-turn antenna 17 and the wafer W are all arranged coaxially with respect to the axis of the process chamber 7.
Therefore, the magnetic field generated by the multi-turn antenna 17 has an effect of efficiently drawing out and confining the helicon wave plasma P _H diffused from the bell jar 1, and suppresses the consumption of chemical species by the chamber wall. However, it is possible to perform uniform dry etching on the wafer W.

A magnet 22 is provided around the outer periphery of the process chamber 7 below the cylinder 16 to more strictly converge the divergent magnetic field in the vicinity of the wafer W. The arrangement position of the magnet 22 is not limited to the illustrated example, and may be another place such as around the support column of the substrate stage 9. Further alternatively, it may be replaced with a solenoid coil for forming a mirror magnetic field.

In such a device, the helicon wave plasma P
_In order to generate _H and inductively coupled plasma P _I at the same time, as shown in FIG. 4, both switches 20 and 21 are turned on.
Let N. At this time, the helicon wave plasma P diffused from the bell jar 1 is introduced into the process chamber 7.
_H and the gas introduced from the gas supply pipe 5 are newly dissociated by the inductively coupled discharge to generate inductively coupled plasma P _I
And coexist. At this time, the phases of the high frequencies applied to the loop antenna 2 and the multi-turn antenna 17 are shifted from each other by 1/2 cycle, so that stable discharge continues.

On the other hand, when it is desired to generate only the helicon wave plasma P _H , the switch 20 is used as shown in FIG.
Is turned on and the switch 21 is turned off. As a result, the plasma existing in the process chamber 7 is only the helicon wave plasma P _H diffused from the bell jar 1. Although not described with reference to the drawings, in the etching apparatus having the above configuration, the switch 20 is set to OF
Of course, it is also possible to generate only the inductively coupled plasma P _I by turning F and the switch 21 ON.

Example 4 In this example, the Al / W based laminated wiring film was etched using the hybrid type etching apparatus described in Example 3. This process will be described with reference to FIGS. FIG. 6 shows a cross section of the main part of the wafer used as the etching sample in this example. In this wafer, an Al / W based laminated wiring film 48 is formed on a SiO _x interlayer insulating film 41, and a resist mask 49 is further formed thereon.
Are formed with a predetermined pattern. Here, the Al / W system laminated wiring film 48 is a Ti system barrier metal 44, a W film 45, an Al-4% Cu film 46, and a T film.
The iON antireflection film 47 is sequentially laminated, and the Ti-based barrier metal 44 is, for example, a Ti film 42 and a TiN film 43 sequentially laminated from the lower layer side.

The resist mask 49 is, for example, a KrF excimer film made of a chemically amplified resist material.
The pattern width is, for example, 0.25 μm through laser lithography.

This wafer is set on the substrate stage 9 of the etching apparatus described in the third embodiment, and the switches 20 and 21 are both turned on as shown in FIG.
The antireflection film 47 and the Al-4% Cu film 46 were used as an example and etched under the following conditions. Here, the frequency of the bias applying RF power source 12 was set to 2 MHz. BCl ₃ flow rate 80 SCCM Cl ₂ flow rate 120 SCCM Gas pressure 0.13 Pa Source power (P _H , P _I excitation) 2500 W (1
3.56 MHz) RF bias power 100 W (2
MHz) Substrate stage temperature 20 ° C. (water cooling) Here, the ion assist mechanism by ions abundantly contained in the helicon wave plasma P _H and radicals abundantly contained in the inductively coupled plasma P _I works smoothly, and Cu rapidly Was removed. As a result, as shown in FIG.
A TiON antireflection film pattern 47a and A having a good anisotropic shape without generating residues or particles
The 1-4% Cu film pattern 46a was obtained.

Next, in order to etch the remaining W film 45 and the barrier metal 44 using only the helicon wave plasma P _H , the switch 21 is turned off as shown in FIG. 5, and etching is performed under the following conditions as an example. went. SF ₆ flow rate 30 SCCM Cl ₂ flow rate 20 SCCM gas pressure 0.13 Pa source power (P _H) 2500 W (13.5
6 MHz) RF bias power 100 W (2 MH
z) Substrate stage temperature 20 ° C. In this process, the W film 45, the TiN film 43 and the T film, which are originally etched in a mode close to ion sputtering, are used.
The i film 42 was rapidly etched by the abundant ions in the helicon wave plasma P _H. In addition, since the amount of radicals generated is small, undercut did not occur in the W film 45 during overetching.

As a result, finally, as shown in FIG. 8, the Al-based wiring pattern 36 having a good anisotropic shape.
It was possible to obtain a.

Embodiment 5 In this embodiment, an example of the structure of an ICP etching apparatus to which the present invention is applied will be described. FIG. 9 shows a conceptual configuration of this etching apparatus. Most of the wall surface of the process chamber 54 of this apparatus is made of a conductive material such as stainless steel, but a part of it in the axial direction is a cylinder 53 made of quartz. turn·
The antenna 58 is wound. The multi-turn antenna 58 is connected to the first RF power source 60 for plasma excitation.
A high frequency is applied through the matching network (M / N) 59 of. Here, the RF for plasma excitation is used.
The frequency of the power supply 60 was set to 2 MHz.

The inside of the process chamber 54 is evacuated to a high vacuum in the direction of arrow D through an exhaust hole 55 by an exhaust system (not shown), and is required for dry etching in the direction of arrow E from a gas supply pipe 57 opened at the bottom surface. It is designed to be supplied with various gases. The process chamber 54 also houses a conductive substrate stage 56 that is electrically insulated from its wall surface, on which a wafer W, for example, is held as a substrate to be processed, and a predetermined dry etching is performed. Has been done. The substrate stage 5
6, a bias application RF power source 62 for applying a substrate bias to the wafer W in order to control the energy of ions incident from the inductively coupled plasma P _I is provided with a second matching network (M / N) 61. Connected through. Here, the frequency of the bias applying RF power source 62 was set to 1.8 MHz, which was slightly lower than the frequency of the plasma exciting RF power source 60 in order to prevent interference.

Further, the upper lid of the process chamber 54 is composed of a top plate 52 made of Al, and the top plate 52 is heated by the heater 51 from the back surface side. The top plate 52 functions as a DC ground electrode for P _{I in the} inductively coupled plasma and also serves as a supply source of Al during etching. When the Al-4% Cu film as described in Example 2 or Example 4 is etched by using the ICP etching apparatus of this example, the top plate 52 is formed.
The reaction between CuCl _x and AlCl _x occurs on the surface of the. Therefore, it is possible to prevent residues and particles derived from Cu and to perform favorable high-speed anisotropic processing.

The present invention has been described above based on the five embodiments, but the present invention is not limited to these embodiments. For example, in the above-described embodiment, the source power frequencies for helicon wave plasma excitation and ICP excitation of the etching apparatus are both 13.56 MHz, but different frequencies may be used between the two. In this case, the phase shifter is not necessary. Further, in the case of helicon wave plasma, electrons of a specific type can be accelerated by the applied frequency, so that the optimum frequency can be selected according to the type of the target process.

In addition to the above, it goes without saying that the configuration of the etching apparatus, the configuration of the sample wafer, and the details of the dry etching conditions can be changed as appropriate.

[0054]

As is apparent from the above description, when the present invention is applied, etching of a Cu-containing Al-based material film can be performed.
It can be performed without generating a residue or particles derived from Cu, and without heating the substrate to a high temperature. Moreover, since highly accurate etching can be realized with a relatively simple structure in which an Al-based member is provided on a part of the inner wall surface of the process chamber of the high-density plasma apparatus and is heated, the economical efficiency is extremely high.

Therefore, according to the present invention, the practical value of the Cu-containing Al-based material film is remarkably increased, and the dry etching thereof is made highly accurate, so that the semiconductor device is highly integrated,
This greatly contributes to high reliability.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing one configuration example of a helicon wave plasma etching apparatus configured by applying the present invention.

FIG. 2 is a schematic cross-sectional view showing a state of a wafer before etching in a process in which the present invention is applied to dry etching of an Al-based wiring film.

3 is a schematic cross-sectional view showing a state where the Al-based wiring film of FIG. 2 is etched.

FIG. 4 is a schematic cross-sectional view showing a state in which both helicon wave plasma and ICP are excited in the hybrid type plasma etching apparatus configured by applying the present invention.

FIG. 5 is a schematic sectional view showing a state where only helicon wave plasma is excited in the hybrid type plasma etching apparatus.

FIG. 6 is a schematic cross-sectional view showing a state of a wafer before etching in a process in which the present invention is applied to dry etching of an Al / W system laminated wiring film.

7 is a schematic cross-sectional view showing a state where the TiON antireflection film and the Al-4% Cu film of FIG. 6 are etched.

8 is a schematic cross-sectional view showing a state where the W film and the barrier metal in FIG. 7 are etched.

FIG. 9 is a schematic sectional view showing an example of the configuration of an ICP plasma etching apparatus configured by applying the present invention.

FIG. 10 is a schematic cross-sectional view showing a state in which a residue derived from Cu is generated during dry etching of a conventional Cu-containing Al-based wiring film.

[Explanation of symbols]

 1 bell jar 2 loop antenna 3a inner circumference side solenoid coil 3b outer circumference side solenoid coil 4,51 heater 6,52 top plate 7,54 process chamber 9,56 substrate stage 12,62 bias power supply RF power source 15,60 RF power source for plasma excitation 16,53 cylinder 17,58 multi-turn antenna 35,46 Al-4% Cu film W wafer

Claims (5)

[Claims] 1. A high vacuum container for accommodating a substrate, and at least one plasma generating means for generating a high density plasma having an ion density of 10 ¹¹ / cm ³ or more in the high vacuum container, A plasma apparatus in which at least a part of an inner wall surface of a container is configured by using an Al-based member, and a heating unit for heating the Al-based member is provided. 2. The plasma generating means includes helicon wave plasma generating means having a plasma generating chamber which is orbited by the first high frequency antenna and the magnetic field generating means and which is connected to the high vacuum container. The plasma apparatus according to claim 1, wherein the plasma apparatus is a plasma apparatus. 3. The plasma generating means includes a non-conductive member forming a part of the high vacuum container in the axial direction, and a second high-frequency antenna wound around the outer peripheral side of the non-conductive member. 3. The plasma device according to claim 1, further comprising an inductively coupled plasma generation unit having the same. 4. The Al-based member constitutes at least a region of the inner wall surface of the high-vacuum container facing the substrate, according to any one of claims 1 to 3. Plasma device. 5. The plasma device according to claim 1, wherein the copper-containing aluminum-based material film on the substrate housed in the high vacuum container is treated with chlorine-based gas. A dry etching method characterized by etching.