JPH0888229A - Formation of wiring - Google Patents

Abstract

PURPOSE: To form a barrier layer for Cu wiring at such a low temperature that at which a semiconductor element is not deteriorated. CONSTITUTION: A TiN barrier layer 12, Cu layer 14, and TiN etching mask 20 which also works as an upper barrier layer are successively formed on a substrate 10. Then the Cu layer 14 and barrier layer 12 are successively etched to wiring through the mask 20 by using the RIE method. At the time of etching the layers 14 and 12, a mixed gas of TiCl4 , Cl2 , and N2 is used as an etching gas so that a TiN side-wall barrier layer 22 can be deposited on the etching-side wall surface while the layers 20, 14, and 12 are etched. In addition, the etching and deposition of the barrier layer 22 can be performed at such a low temperature that at which a semiconductor element is not deteriorated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring forming method, particularly C
The present invention relates to a wiring forming method suitable for forming u wiring.

[0002]

2. Description of the Related Art When wirings are miniaturized to increase the integration of semiconductor devices or the operating speed of semiconductor devices is increased, the wiring current density increases, so that EM (Elec
There is a problem that the reliability of the wiring is deteriorated due to the migration. Since Al wiring, which is widely used at present, is inferior in EM resistance, various wiring materials to replace it are being studied. In recent years, Cu has attracted attention as one of the wiring materials that replaces Al, and a research report on the Cu wiring formation technology has been published in the literature: IEICE Technical Report SDM89-8.
5 p25-29 1989.

According to this technique, a mixed gas of CCl ₄ and N ₂ is used as an etching gas, and RIE (Rea
Cu by the active Ion Etching method.
Is etched into a wiring shape. Then Cu and T
The alloy film of i is laminated on Cu after processing, and this alloy film is
Etching is performed by the RIE method similarly to Cu. After that, the alloy film is heated at 800 ° C. while being kept in an N ₂ gas atmosphere to form a TiN barrier layer covering Cu.

[0004]

However, in the above-mentioned prior art, the heat treatment temperature for forming the TiN barrier layer is as high as 800 ° C. Therefore, when the wiring is formed on the substrate after the semiconductor element such as the MOSFET is formed on the substrate, the element characteristics may be deteriorated by the high temperature heat treatment. In order to prevent this, it is desired to reduce the formation temperature of the barrier layer.

In addition to this, from the viewpoint of improving the reliability of Cu wiring, SM (stress) of Cu wiring is
It is desired to improve the resistance to smigration) and / or the resistance to EM. Alternatively, C that causes Cu wiring corrosion
It is desired to form a barrier layer having a low content of l.
Alternatively, it is desired to improve the barrier property of the barrier layer, for example, the property of preventing diffusion of wiring constituent elements to the outside of the wiring and the property of preventing impurities from entering the wiring.

The invention of claim 1 is made in view of the above-mentioned point, and the wiring forming method capable of reducing the formation temperature of the barrier layer covering the wiring and improving the SM resistance and / or the EM resistance of the wiring. The purpose is to provide.

The invention of claim 5 and the invention of claim 16 are
The present invention has been made in view of the above points, and provides a wiring forming method capable of reducing the formation temperature of a barrier layer covering wiring and forming a barrier layer having a low content of Cl that causes wiring corrosion. With the goal.

The invention of claim 10 and the invention of claim 21 are made in view of the above-mentioned points, and a barrier layer which can reduce the formation temperature of the barrier layer for covering the wiring and has an excellent barrier property. An object of the present invention is to provide a wiring forming method that can be formed.

[0009]

Means and Actions for Solving the Problems The wiring forming methods of the inventions of claim 1, claim 5 and claim 10 have a common configuration in the following points.

That is, the wiring forming method according to the first, fifth and tenth aspects of the present invention comprises a step of sequentially laminating a lower barrier layer and a wiring main material layer on a base, and a wiring main material layer. While etching the wiring main material layer into the wiring shape by the process of forming an etching mask that also serves as the upper barrier layer and the reactive ion etching method, the etching mask side wall surface of the wiring main material layer mainly reacts with the etching mask. A step of depositing a sidewall barrier layer made of a reaction product with an etching gas, the reactive etching gas being a main source gas made of chloride containing a sidewall barrier constituent element,
The etching mask is formed by mixing a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer and a nitrogen-based gas containing N for preventing side etching of the wiring main material layer. Consisting of a film containing the constituent elements,
It has a common configuration.

Therefore, claim 1, claim 5 and claim 10
According to the invention, the following common effects can be achieved.

That is, according to the inventions of claim 1, claim 5 and claim 10, when etching the wiring main material layer, a reaction product is generated between the etching mask and the reactive etching gas. . Then, the side wall barrier layer is formed mainly by depositing this reaction product on the side wall surface of the wiring main material layer that has been etched. Therefore, since the side wall barrier layer can be formed in parallel with the etching, the heat treatment for forming the side wall barrier layer can be omitted, and as a result, the side wall barrier layer can be formed at a lower temperature than in the conventional case. Forming the lower barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique, and forming the etching mask that also serves as the upper barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique and etching technique. Can be achieved.

According to the first, fifth and tenth aspects of the present invention, the laminated thickness of the sidewall barrier layer is set to 0 ° C. and 1 atm for the sidewall barrier constituent element and the chlorine element contained in the reactive etching gas. In (1), it can be changed according to the ratio (1) of the number of side wall barrier constituent elements and chlorine elements supplied per unit time into the etching chamber. Further, side etching may occur in the wiring main material layer during the process of depositing the side wall barrier layer. However, the side etching amount is 0 ° C. when the nitrogen element and the chlorine element contained in the reactive etching gas are 1 ° C. and 1 ° C., respectively. It can be changed according to the ratio (2) of the numbers of nitrogen element and chlorine element supplied per unit time into the etching chamber at atmospheric pressure. These ratios (1) and (2) can be independently controlled by individually adjusting the flow rates of the main raw material gas, the chlorine-based gas, and the nitrogen-based gas contained in the reactive etching gas, so that the sidewall barrier layer stacking is performed. The thickness and the amount of side etching can be controlled independently.

Further, in carrying out the invention of claims 1, 5 and 10, it is preferable that the etching mask also serving as the upper barrier layer is a multilayer film. When an etching mask composed of a first layer and a second layer, which are sequentially stacked on the wiring main material layer, is formed, a sidewall barrier layer is formed by a reaction between the second layer and the reactive etching gas. Should be left as the upper barrier layer. In this case, the first layer can function as an etching stop layer made of a material having an etching rate lower than that of the second layer, and thus overetching of the second layer left as the upper barrier layer can be prevented. Alternatively, the first layer can function as an adhesion layer made of a material having good adhesion to the wiring main material layer. When an etching mask composed of a first layer, a second layer, and a third layer, which are sequentially stacked on the wiring main material layer, is formed, a sidewall barrier layer is formed by the reaction between the third layer and the reactive etching gas. However, it is preferable that the first layer and the second layer remain as the upper barrier layer.
In this case, the first layer is made to function as an adhesion layer made of a material having good adhesion to the wiring main material layer, and the second layer is made of an etching stopper made of a material having an etching rate lower than that of the third layer. It has the advantage that it can function as a layer.

Further, claim 1, claim 5 and claim 10
Of the invention is different in the following points, and therefore the operation is different.

That is, in the wiring forming method according to the first aspect of the present invention, as the main raw material gas contained in the reactive etching gas, T
One or both of i chloride and Zr chloride are used, and selected from a Ti film, a Zr film, a compound film containing one of Ti and Zr, and a compound film containing both Ti and Zr as an etching mask. It has a structure in which a single layer film made of one kind of film or a multilayer film made of plural kinds of films is used.

Therefore, according to the invention of claim 1, since the side wall barrier layer is a reaction product of the reactive etching gas and the etching mask, Ti and Z are used as the side wall barrier layer.
A sidewall barrier layer made of a compound containing one of r or T
A sidewall barrier layer made of a compound containing both i and Zr can be formed. As the sidewall barrier layer, TiN, TiO
N, ZrN, ZrON, TiZr, TiZrN or Ti
It is preferred to form ZrON.

The coefficient of thermal expansion of the compound containing one or both of Ti and Zr has a small difference from the coefficient of thermal expansion of Cu, so that the side wall barrier layer made of such a compound is Cu.
Of the wiring main material layer made of a material having improved SM resistance of the wiring main material layer or having a thermal expansion coefficient similar to that of Cu.
Helps improve tolerance. In order to improve the SM resistance of the wiring main material layer, the sidewall barrier layer, the lower barrier layer and the upper barrier layer have a thermal expansion coefficient equal to or close to the thermal expansion coefficient of the wiring main material layer. It is preferably formed of a material. The SM resistance can be effectively improved by reducing the difference between the thermal expansion coefficients of the sidewall barrier layer, the lower barrier layer and the upper barrier layer and the thermal expansion coefficient of the wiring main material layer.

Further, since the compound containing one or both of Ti and Zr has conductivity, the sidewall barrier layer made of such a compound is useful for improving the EM resistance of the wiring main material layer. In order to improve the EM resistance of the wiring main material layer,
The side wall barrier layer, the lower barrier layer and the upper barrier layer are preferably formed of a conductive material. By forming the sidewall barrier layer, the lower barrier layer, and the upper barrier layer with a conductive material, the EM resistance can be effectively improved.

The wiring forming method according to the fifth aspect of the present invention has a structure in which at least NH ₃ is used as the nitrogen-based gas contained in the reactive etching gas.

Therefore, according to the invention of claim 5, in the process of depositing the side wall barrier layer, NH ₃ promotes the dissociation of the side wall barrier constituent element and Cl in the main source gas, so that in the process of depositing the side wall barrier layer. It is possible to reduce the amount of Cl that is taken in by.

A wiring forming method according to a tenth aspect of the invention is
The sidewall barrier layer is a barrier layer containing oxygen, and the reactive etching gas is mixed with an oxygen-based gas containing O for controlling the oxygen content of the sidewall barrier layer.

Therefore, according to the tenth aspect of the invention, the oxygen element and the nitrogen element contained in the reactive etching gas are 0 or less.
The oxygen content of the sidewall barrier layer can be controlled by the ratio (3) of the numbers of oxygen elements and nitrogen elements supplied per unit time into the etching chamber at 1 ° C. and 1 atmosphere. Since the barrier property of the sidewall barrier layer containing oxygen changes depending on the oxygen content, the barrier property of the sidewall barrier layer can be controlled by adjusting the ratio (3).

The wiring forming methods of the sixteenth and twenty-first aspects of the present invention have a common configuration in the following points.

That is, in the wiring forming method according to the sixteenth and twenty-first aspects of the invention, a step of sequentially laminating a lower barrier layer, a wiring main material layer and an upper barrier layer on a base, and etching on the upper barrier layer. While the wiring main material layer is being etched into a wiring shape by the step of forming a mask and the reactive ion etching method, the reaction between the etching mask and the reactive etching gas is mainly generated on the side wall surface of the etching processing of the main wiring material layer. A step of depositing a sidewall barrier layer made of a substance, the reactive etching gas is a main source gas made of chloride containing a sidewall barrier constituent element, and a chlorine containing chlorine for controlling the thickness of the sidewall barrier layer. The etching mask is formed by mixing a system gas and a nitrogen-based gas containing N for preventing side etching of the wiring main material layer. That consists of free films, have a common configuration.

Therefore, according to the sixteenth and twenty-first aspects of the invention, the following common operation can be achieved.

That is, according to the sixteenth and twenty-first aspects of the invention, when etching the wiring main material layer,
A reaction product is generated between the etching mask and the reactive etching gas. Then, the side wall barrier layer is formed mainly by depositing this reaction product on the side wall surface of the wiring main material layer that has been etched. Therefore, since the side wall barrier layer can be formed in parallel with the etching, the heat treatment for forming the side wall barrier layer can be omitted, and as a result, the side wall barrier layer can be formed at a lower temperature than in the conventional case. Forming the lower barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique, and forming the etching mask that also serves as the upper barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique and etching technique. Can be achieved.

According to the sixteenth and twenty-first aspects of the invention, the laminated thickness of the side wall barrier layer is set to 0 ° C. for the side wall barrier constituent element and chlorine element contained in the reactive etching gas,
It can be changed in accordance with the ratio (1) of the numbers of the sidewall barrier constituent element and the chlorine element supplied per unit time into the etching chamber at 1 atm. Further, side etching may occur in the wiring main material layer during the process of depositing the side wall barrier layer. However, the side etching amount is 0 ° C. when the nitrogen element and the chlorine element contained in the reactive etching gas are 1 ° C. and 1 ° C., respectively. It can be changed according to the ratio (2) of the numbers of nitrogen element and chlorine element supplied per unit time into the etching chamber at atmospheric pressure. These ratios (1) and (2) can be independently controlled by individually adjusting the flow rates of the main raw material gas, the chlorine-based gas, and the nitrogen-based gas contained in the reactive etching gas, so that the sidewall barrier layer stacking is performed. The thickness and the amount of side etching can be controlled independently.

Further, in carrying out the invention of claims 16 and 21, the upper barrier layer is a multilayer film formed by sequentially laminating an adhesion layer and an etching stop layer on the wiring main material layer. It is suitable. By forming the adhesion layer with a material having good adhesion to the wiring main material layer, the adhesion between the upper barrier layer and the wiring main material layer can be enhanced. Further, by forming the etching stop layer with a material having an etching rate lower than that of the etching mask, it is possible to prevent the upper barrier layer from being over-etched during the reactive ion etching at the time of depositing the sidewall barrier layer, or to prevent the over-etching. The amount can be reduced.

Further, the inventions of claim 16 and claim 21 differ in the structure in the following point, and therefore the operation is different.

That is, the wiring forming method of the sixteenth aspect of the present invention has a configuration in which at least NH ₃ is used as the nitrogen-based gas contained in the reactive etching gas.

Therefore, according to the sixteenth aspect of the present invention, NH ₃ promotes the dissociation of the side wall barrier constituent element and Cl in the main source gas in the process of depositing the side wall barrier layer. The incorporated Cl can be reduced.

The wiring forming method according to the twenty-first aspect of the invention is
The sidewall barrier layer is a barrier layer containing oxygen, and the reactive etching gas is mixed with an oxygen-based gas containing O for controlling the oxygen content of the sidewall barrier layer.

Therefore, according to the twenty-first aspect, the oxygen element and the nitrogen element contained in the reactive etching gas are 0 or less.
The oxygen content rate of the sidewall barrier layer can be controlled according to the ratio (3) of the numbers of oxygen elements and nitrogen elements supplied per unit time into the etching chamber at 1 ° C. and 1 ° C. Since the barrier property of the sidewall barrier layer containing oxygen changes depending on the oxygen content, the barrier property of the sidewall barrier layer can be controlled by adjusting the ratio (3).

[0035]

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 3 are process drawings for explaining the embodiments of the inventions of claims 1, 5 and 10. 1 to 3 below
Examples of these inventions will be described with reference to FIG. The conditions for forming a thin film, materials to be used, processing temperature, processing time, film thickness, gas flow rate, and other conditions described below are merely examples, and therefore these conditions are not limited to those described below.

[0037] In the first embodiment of the invention of claim 1 This example, TiCl 4 as a main source _gas, the N ₂ is used as Cl ₂ and nitrogen-based gas as a chlorine-based gas, a reactive etching gas, these A mixed gas of TiCl ₄ , Cl ₂ and N ₂ is used. Therefore, the main source gas is a chloride containing Ti which is a constituent element of the sidewall barrier. A single layer film made of TiN is used as an etching mask. Therefore, the etching mask is a film containing Ti as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer and Wiring Main Material Layer Sequentially on Underlayer) First, in this embodiment, a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element are formed. Prepare a base 10 consisting of and
The TiN lower barrier layer 12 having a thickness of about 0.1 μm and Cu having a thickness of about 0.6 μm are sequentially deposited on the upper side by a sputtering method.
The wiring main material layer 14 is laminated (FIG. 1 (A) to FIG. 1).
(B)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
By the DC sputtering method with r, the TiN lower barrier layer 1
Stack two. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas.

(2: Step of forming an etching mask which also functions as an upper barrier layer on the wiring main material layer) Next, in this embodiment, a thickness of about 1.0 μm is formed on the Cu wiring main material layer 14 by the sputtering method. The TiN mask material 16 is laminated (FIG. 1C).

A semiconductor element such as MOSFET is formed on the base 10.
Even when the TiN lower barrier layer 12 is formed, according to a conventionally known thin film forming technique such as a sputtering method, the TiN lower barrier layer 12 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element.
The Cu wiring main material layer 14 and the TiN mask material 16 can be laminated.

The TiN lower barrier layer 12 and the TiN mask material 16 can be made of Ti _X N _1-X (0.5 ≦ X ≦ 1, for example X = 0.5).

Next, a resist is applied to the TiN mask material 16 to a thickness of 1 μm, and then the resist is exposed and developed to form a resist pattern 18 (FIG. 2).
(A)). The planar shape of the resist pattern 18 is a wiring shape.

Next, a conventionally known dry etching technique, here reactive ion etching (RIE: Reacti)
The TiN mask material 16 is etched into a wiring shape through the resist pattern 18 by a ve Ion Etching) method to form a TiN etching mask 20 made of this material 16 (FIG. 2B). The TiN etching mask 20 also serves as the upper barrier layer, and the portion remaining on the Cu wiring main material layer 14 after the deposition of the sidewall barrier layer described later functions as the upper barrier layer.

When forming the TiN etching mask 20, it is preferable to select etching conditions so that the TiN mask material 16 is etched but the Cu wiring main material layer 14 is not etched. For example, in the case of reactive ion etching, the etching is performed with Cl ₂ as the reactive etching gas and room temperature as the base temperature,
The TiN mask material 16 can be etched so as not to etch the Cu wiring main material layer 14.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Next, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 3).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
By a reactive ion etching method using a mixed gas of TiCl ₄ , Cl ₂ and N ₂ as a reactive etching gas, T
Cu wiring main material layer 14 through the iN etching mask 20
And the TiN lower barrier layer 12 are sequentially etched to process the main material layer 14 and the barrier layer 12 into a wiring shape. During this etching process, a reactive etching gas, which is a mixed gas of TiCl ₄ , Cl ₂ and N ₂ , and TiN
The reaction product TiN with the etching mask 20 is TiN
The TiN side wall barrier layer is deposited on the side wall surface 20a of the etching mask 20, the side wall surface 14a of the Cu wiring main material layer 14 and the side wall surface 12a of the lower barrier layer 12, and is thus formed by this reaction product. 22 can be deposited on these sidewall surfaces 20a, 14a and 12a in a self-aligned manner. Further, after the etching process of the TiN lower barrier layer 12 is completed, the TiN etching mask 20 remaining on the Cu wiring main material layer 14 is the TiN upper barrier layer 2.
Function as 4. Therefore, it is processed into a wiring shape and TiN
Lower barrier layer 12, TiN upper barrier layer 24 and TiN
The Cu wiring main material layer 14 covered with the sidewall barrier layer 22 can be obtained (FIG. 3B).

Even when the semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 and the TiN lower barrier layer are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. 12 can be etched and a TiN sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. A magnetron reactive ion etching apparatus is used as an etching apparatus, the gas flow rates of TiCl ₄ , Cl ₂ and N ₂ contained in the reactive etching gas are 20 SCCM, 10 SCCM and 120 SCCM, respectively, the etching gas pressure is 35 mTorr, and the RF power is 500 W. The base temperature during etching is set to a temperature suitable for etching the Cu wiring main material layer 14. The etching of Cu was generated by the reaction with Cl in the etching gas (CuCl)
₃ progresses as it vaporizes, but this is because the vapor pressure of this (CuCl) ₃ is low. It is known that the base temperature must be heated to 250 to 400 ° C. for the vaporization, and the base temperature is 300 ° C. here. Hereinafter, the etching conditions exemplified here will be referred to as etching conditions a.

In addition to changing the base temperature variously, when etching is performed under the above-mentioned etching conditions a,
FIG. 4 shows the relationship between the base temperature and the etching rate of Cu. The horizontal axis of FIG. 4 shows the base temperature [° C.] and the vertical axis shows the etching rate of Cu [nm / min]. The values obtained by measurement in the experiment are shown by plotting with white circles.

As can be understood from FIG. 4, when the base temperature is in the range of 230 to 300 ° C., C increases as the base temperature increases.
The etching rate of u increases, and the base temperature becomes 30
When the temperature exceeds 0 ° C., the Cu etching rate becomes almost saturated (the etching rate becomes almost constant). In order to prevent deterioration of the characteristics of the semiconductor element formed on the underlayer 10 and increase the etching rate of Cu, it is preferable to set the underlayer temperature low. Therefore, the underlayer temperature is set to about 300 ° C. at which the saturation of the etching rate begins. It turns out that it is better to set the temperature.

Further, Ti element and Cl contained in the etching gas
The total number of Ti elements, the total number of Cl elements, and the total number of N elements, which are elements and N elements and are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atmospheric pressure, are [Ti], Expressing [Cl] and [N], the side etching amount of the Cu wiring main material layer 14 at the time of depositing the TiN side wall barrier layer 22 is represented by the ratio [N] / [C].
1] and the sidewall barrier layer 22.
Can be controlled according to the magnitude of the ratio [Ti] / [Cl].

[0054] The etching gas is a mixed gas of TiCl _4, Cl ₂ and _{N 2,} TiCl ₄ in etching for depositing a sidewall barrier layer 22, Cl ₂ and _{N 2}
[Ti], [Cl] and [N] are as follows when the gas flow rates of 20 SCCM, 10 SCCM and 120 SCCM are respectively set.

The number of Ti elements and the number of Cl elements contained in TiCl ₄ per unit volume (here, 1000 cc) at 0 ° C. and 1 atmospheric pressure are Apogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ x1 = 6.02 × 10 ²³ Ti element, Cl
Regarding the element 6.02 × 10 ²³ × 4 = 2.408 × 1
It becomes 0 ²⁴ . Similarly, at 0 ° C. and 1 atm, the number of Cl elements contained in Cl ₂ per unit volume is 6.02 × 1.
^{0 23 × 2 = 1.204 × 10} 24 pieces, 0 ° C., the number of N _{elements N 2} contains per unit volume in 1 atm 6.
It becomes 02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ pieces.

Therefore, TiCl ₄ gas flow rate: 20 SCC
When the gas flow rate of M and Cl ₂ is 10 SCCM and the gas flow rate of N ₂ is 120 SCCM, the number of each element flowing into the etching chamber per unit time (here, per minute) at 0 ° C. and 1 atmospheric pressure is [Ti] = 6.02 x 10 ²³
× (20/1000) = 1.2 × 10 ²² pieces, [Cl]
= 2.408 × 10 ²⁴ × (20/1000) +1.2
04 × 10 ²⁴ × (10/1000) = 6.02 × 10
²² pieces, [N] = 1.204 × 10 ²⁴ × (120/1
000) = 1.44 × 10 ²³ pieces. Since the etching gas is a mixed gas of TiCl _4, Cl ₂ and _{N 2,} by adjusting any suitably These TiCl _4, Cl ₂ and _{N 2} gas flow rate, respectively, the ratio [N] /
[Cl] and the ratio [Ti] / [Cl] can be controlled independently.

FIG. 5 is a diagram showing the relationship between the ratio [N] / [Cl] and the side etching amount of the wiring main material layer. In the figure, Ti is formed on the underlayer 10 in the same manner as the above-mentioned embodiment.
The N lower barrier layer 12, the Cu wiring main material layer 14 and the TiN mask material 16 are laminated, and a SiO ₂ etching mask is further formed on the TiN mask material 16. Then, when the TiN mask material 16 is etched through the SiO ₂ etching mask by the reactive ion etching method,
The side etching amount of the Cu wiring main material layer 14 is experimentally examined. At the time of this etching, except that the gas flow rate of the nitrogen-based gas N ₂ contained in the etching gas is changed to variously change [N] / [Cl], an experiment is performed in the same manner as the above-mentioned etching condition a. The horizontal axis of the figure shows the ratio [N] / [Cl] and the vertical axis shows the side etching amount [μ].
[m]] and showed. The values obtained by measurement in the experiment are shown by plotting with white circles.

As can be understood from FIG. 5, the ratio [N] /
As [Cl] increases, the side etching amount of the Cu wiring main material layer 14 decreases, and when [N] / [Cl] exceeds about 2, the side etching amount is almost zero, that is, the side etching of the Cu wiring main material layer 14 is performed. Can be understood to disappear.

Therefore, in order to prevent the side etching of the Cu wiring main material layer 14, it is preferable that [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> 0. Recognize.

Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
Side etching can be prevented, and the side wall barrier layer 2
Since the etching of the side wall barrier layer 22 is stopped at the deposition position of 2, the overetching of the Cu wiring main material layer 14 can be prevented or the amount of the overetching can be reduced, so that the Cu wiring main material layer 14 can be wired without trouble. Can be processed into a shape.

FIG. 6 is a diagram showing the relationship between the ratio [Ti] / [Cl] and the thickness of the sidewall barrier layer. In the figure, similar to the above-described embodiment, the TiN lower barrier layer 12, the Cu wiring main material layer 14, and the TiN mask material 16 are laminated on the underlayer 10, and then the TiN etching mask 20 is formed. To form. Then, by the reactive ion etching method, T
TiN mask material 16 through the iN etching mask 20
The thickness of the TiN sidewall barrier layer 22 in the case of etching was investigated experimentally. At the time of this etching, except that the gas flow rate of the main raw material gas TiCl ₄ contained in the etching gas is changed to variously change [Ti] / [Cl], an experiment is performed in the same manner as in the etching condition a. The experimental results are shown by taking the ratio [Ti] / [Cl] on the horizontal axis and the thickness of the sidewall barrier layer 22 (thickness in the direction along the base surface) [nm] on the vertical axis. The values obtained by the measurement in the experiment are plotted in black squares.

As can be understood from FIG. 6, [Ti] /
When [Cl] is in the range of approximately 0.13 to 0.17, [T
The thickness of the sidewall barrier layer 22 increases as i] / [Cl] increases, and [Ti] / [Cl] is approximately 0.17 to 0.2.
In the range of 0, the thickness of the sidewall barrier layer 22 is constant at about 70 nm.

Therefore, by setting [Ti] / [Cl] = 0.2, the sidewall barrier layer 22 having a thickness of 70 nm can be formed, and this thickness prevents oxidation of the Cu wiring main material layer 14 and diffusion of Cu. Thick enough to do so.

Further, when the etching of the TiN lower barrier layer 12 into the wiring shape is completed, in order to generate the remaining portion of the TiN etching mask 20 functioning as the TiN upper barrier layer 24, T before the etching is started.
The thickness T _E of the iN etching mask 20 may be set so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of wiring main material layer 14] / [etching rate of wiring main material layer 14] + [thickness of lower barrier layer 12] / [ Etching Rate of Lower Barrier Layer 12]} According to this example, the following advantages can be obtained.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Secondly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of TiN, the thermal expansion coefficient of these TiN barrier layers 12, 24 and 22 and the heat of the Cu wiring main material layer 14 are increased. The difference from the expansion coefficient can be reduced. Therefore, these barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22 are made of TiN, the TiN barrier layers 12, 24 and 22 are electrically conductive. Therefore, by these barrier layers 12, 24 and 22,
The EM resistance of the wiring main material layer 14 can be improved.

[0069] In the second embodiment of the present invention defined in claim 1] This embodiment, except using N _{2 O} addition to the N ₂ as nitrogen-based gas of the etching gas, a first embodiment of the invention of claim 1 described above Similar to the example, TiON is used as the sidewall barrier layer 22.
Deposit. TiON has the effect of suppressing the diffusion of Cu to the same extent as TiN or more.

In this embodiment, TiCl ₄ , C during etching for depositing the sidewall barrier layer 22 is used.
The gas flow rates of l ₂ , N ₂ and N ₂ O were respectively 20 SC
In the case of CM, 10 SCCM, 115 SCCM and 5 SCCM, [Ti], [Cl] and [N] are as follows.

The number of Ti elements and the number of Cl elements contained in TiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atm are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ x1 = 6.02 × 10 ²³ Ti element, Cl
Regarding the element 6.02 × 10 ²³ × 4 = 2.408 × 1
It becomes 0 ²⁴ . Similarly, at 0 ° C. and 1 atm, the number of Cl elements contained in Cl ₂ per unit volume is 6.02 × 1.
^{0 23 × 2 = 1.204 × 10} 24 pieces, 0 ° C., the number of N _{elements N 2} contains per unit volume in 1 atm 6.
02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ , and N contained in N ₂ O per unit volume at 0 ° C. and 1 atm.
The number of elements is 6.02 × 10 ²³ × 2 = 1.204 × 1
It becomes 0 ²⁴ .

Therefore, TiCl ₄ gas flow rate: 20 SCC
M, Cl ₂ gas flow rate; 10 SCCM, N ₂ gas flow rate; 115 SCCM, N ₂ O gas flow rate; 5 SCCM per unit time at 0 ° C. and 1 atmosphere (here, 1
The number of each element flowing into the etching chamber per minute is [Ti] = 6.02 × 10 ²³ × (20/100)
0) = 1.2 × 10 ²² pieces, [Cl] = 2.408 × 1
0 ²⁴ × (20/1000) + 1.204 × 10 ²⁴ ×
(10/1000) = 6.02 × 10 ²² , [N] =
1.204 x 10 ²⁴ x (115/1000) + 1.2
04 x 10 ²⁴ x (5/1000) = 1.44 x 10
²³ . The etching gas is TiCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and N ₂ O is used, these Ti
The ratio [N] / [Cl] and the ratio [Ti] / [Cl] can be independently controlled by adjusting the gas flow rates of Cl ₄ , Cl ₂ , N ₂ and N ₂ O arbitrarily and appropriately.
Further, the oxygen content rate of the TiON side wall barrier layer 22 can be controlled while the [N] is set to a desired number by adjusting the gas flow rates of N ₂ and N ₂ O arbitrarily and suitably.

Also in this embodiment, the following effects can be expected.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element, and the Cu wiring main layer 14 is processed. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, the thermal expansion coefficients of these barrier layers 12, 24 and 22 and the Cu wiring main material layer 14 are made. The difference from the coefficient of thermal expansion can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, the barrier layers 12, 24 and 22 are electrically conductive. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

[0077] In the third embodiment of the present invention defined in claim 1 This example, ZrCl _4, and N ₂ is used as Cl ₂ and nitrogen-based gas as a chlorine-based gas as the main raw material gas, a reactive etching gas, these A mixed gas of ZrCl ₄ , Cl ₂ and N ₂ is used. Therefore, the main source gas is a chloride containing Zr which is a sidewall barrier constituent element. A single layer film made of ZrN is used as an etching mask. Therefore, the etching mask is a film containing Zr as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer and Wiring Main Material Layer Sequentially on Underlayer) First, in this embodiment, a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element are formed. Prepare a base 10 consisting of and
The ZrN lower barrier layer 12 having a thickness of about 0.1 μm and Cu having a thickness of about 0.6 μm are sequentially deposited on the upper side by a sputtering method.
The wiring main material layer 14 is laminated (FIG. 1 (A) to FIG. 1).
(B)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
ZrN lower barrier layer 1 by DC sputtering method with r
Stack two. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas.

(2: Step of forming an etching mask which also functions as an upper barrier layer on the wiring main material layer) Next, in this embodiment, a thickness of about 1.0 μm is formed on the Cu wiring main material layer 14 by the sputtering method. The ZrN mask material 16 is laminated (FIG. 1 (C)).

A semiconductor element such as MOSFET is formed on the base 10.
Even when the ZrN lower barrier layer 12 is formed by a well-known thin film forming technique such as a sputtering method, the ZrN lower barrier layer 12 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element.
The Cu wiring main material layer 14 and the ZrN mask material 16 can be laminated.

The ZrN lower barrier layer 12 and the ZrN mask material 16 may be Zr _X N _1-X (0.5≤X≤1, for example X = 0.5).

Next, a resist is applied to the ZrN mask material 16 to a thickness of 1 μm, and then the resist is exposed and developed to form a resist pattern 18 (FIG. 2).
(A)). The planar shape of the resist pattern 18 is a wiring shape.

Next, a well-known dry etching technique, here reactive ion etching (RIE: Reacti)
The ZrN mask material 16 is etched into a wiring shape through the resist pattern 18 by the ve Ion Etching) method to form a ZrN etching mask 20 made of this material 16 (FIG. 2B). The ZrN etching mask 20 also serves as the upper barrier layer, and the portion remaining on the Cu wiring main material layer 14 after the completion of the deposition of the sidewall barrier layer described later functions as the upper barrier layer.

When forming the ZrN etching mask 20, it is preferable to select the etching conditions so that the ZrN mask material 16 is etched but the Cu wiring main material layer 14 is not etched. For example, in the case of reactive ion etching, the etching is performed with Cl ₂ as the reactive etching gas and room temperature as the base temperature,
The ZrN mask material 16 can be etched so as not to etch the Cu wiring main material layer 14.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Then, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 3).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
By a reactive ion etching method using a mixed gas of ZrCl ₄ , Cl ₂ and N ₂ as a reactive etching gas, Z
Cu wiring main material layer 14 through the rN etching mask 20
And the ZrN lower barrier layer 12 are sequentially etched, and the main material layer 14 and the barrier layer 12 are processed into a wiring shape. During the etching process, a reactive etching gas, which is a mixed gas of ZrCl ₄ , Cl ₂ and N ₂ , and ZrN
The reaction product ZrN with the etching mask 20 is ZrN.
The ZrN side wall barrier layer is deposited on the side wall surface 20a of the etching mask 20, the side wall surface 14a of the Cu wiring main material layer 14 and the side wall surface 12a of the lower barrier layer 12, and is therefore formed of this reaction product. 22 can be deposited on these sidewall surfaces 20a, 14a and 12a in a self-aligned manner. After the etching process of the ZrN lower barrier layer 12 is completed, the ZrN etching mask 20 remaining on the Cu wiring main material layer 14 is the ZrN upper barrier layer 2.
Function as 4. Therefore, it is processed into a wiring shape, and ZrN
Lower barrier layer 12, ZrN upper barrier layer 24 and ZrN
The Cu wiring main material layer 14 covered with the sidewall barrier layer 22 can be obtained (FIG. 3B).

Even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 and the ZrN lower barrier layer are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. 12 can be etched and a ZrN sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. A magnetron reactive ion etching apparatus is used as an etching apparatus, and the gas flow rates of ZrCl ₄ , Cl ₂ and N ₂ contained in the reactive etching gas are 20 SCCM, 10 SCCM and 120 SCCM, respectively, the etching gas pressure is 35 mTorr, and the RF power is 500 W. The base temperature at the time of etching is 250 to 400 ° C. which is suitable for etching the Cu wiring main material layer 14 and here is 300 ° C.
And

In this embodiment, ZrC is used as the main raw material gas.
The etching for depositing the ZrN side wall barrier layer 22 is performed by using l _4, and the reaction mechanism of this etching is the same as that of the first embodiment of claim 1 in which TiCl ₄ is used as the main raw material gas. ZrC as main source gas
In this embodiment using l _4, the relationship between the etching rate of the underlayer temperature and Cu is considered to indicate the same tendency as FIG. Therefore, in order to prevent the deterioration of the characteristics of the semiconductor element formed on the underlayer 10 and increase the etching rate of Cu, saturation of the etching rate of Cu starts at about 30%.
It is preferable to set the base temperature to about 0 ° C.

Zr element and Cl contained in the etching gas
[Zr], the total number of Zr elements, the total number of Cl elements, and the total number of N elements, which are elements and N elements and are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atm, respectively. Expressing [Cl] and [N], the side etching amount of the Cu wiring main material layer 14 at the time of depositing the ZrN side wall barrier layer 22 is expressed by the ratio [N] / [C].
1] and the sidewall barrier layer 22.
Can be controlled according to the magnitude of the ratio [Zr] / [Cl].

[0093] The etching gas is ZrCl _4, a mixed gas of Cl ₂ and _{N 2,} ZrCl ₄ in etching for depositing a sidewall barrier layer 22, Cl ₂ and _{N 2}
[Zr], [Cl], and [N] are as follows when the gas flow rates of 20 SCCM, 10 SCCM, and 120 SCCM are respectively set.

The number of Zr elements and the number of Cl elements contained in ZrCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atm are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Zr element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
It becomes 204 × 10 ²⁴ .

Therefore, the gas flow rate of ZrCl ₄ ; 20SCC
When the gas flow rate of M and Cl ₂ is 10 SCCM and the gas flow rate of N ₂ is 120 SCCM, the number of each element flowing into the etching chamber per unit time (here, per minute) at 0 ° C. and 1 atmospheric pressure is [Zr] = 6.02 x 10 ²³
× (20/1000) = 1.2 × 10 ²² pieces, [Cl]
= 2.408 × 10 ²⁴ × (20/1000) +1.2
04 × 10 ²⁴ × (10/1000) = 6.02 × 10
²² pieces, [N] = 1.204 × 10 ²⁴ × (120/1
000) = 1.44 × 10 ²³ pieces. Since the etching gas is set to ZrCl _4, a mixed gas of Cl ₂ and _{N 2,} by adjusting any suitably These ZrCl _4, Cl ₂ and _{N 2} gas flow rate, respectively, the ratio [N] /
[Cl] and the ratio [Zr] / [Cl] can be controlled independently.

In this embodiment, ZrC is used as the main raw material gas.
The etching for depositing the ZrN side wall barrier layer 22 is performed using l _4, and the reaction mechanism of this etching is the same as that of the first embodiment of the invention of claim 1 in which TiCl ₄ is used as the main raw material gas. it is conceivable that. Therefore, also in this example using ZrCl ₄ as the main source gas, Cu
Side etching amount of wiring main material layer 14 and ratio [N] / [C]
1] shows the same relationship as in FIG. 5, and the relationship between the thickness of the sidewall barrier layer 22 and the ratio [Zr] / [Cl] is as follows.
It is considered that this shows the same relationship as in FIG.

Therefore, in order to prevent side etching of the Cu wiring main material layer 14, it is considered preferable to set [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> 0. To be Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
It is considered that the side etching of the Cu wiring main material layer 14 is prevented or the progress of the etching of the side wall barrier layer 22 is stopped at the deposition portion of the side wall barrier layer 22. Therefore, the Cu wiring main material layer 14 can be processed into a wiring shape without any trouble.

By setting [Zr] / [Cl] = 0.2, it is considered that the ZrN side wall barrier layer 22 having a thickness of 70 nm can be formed. This thickness is determined by oxidation of the Cu wiring main material layer 14 and Cu. Is thick enough to prevent the diffusion of

When the etching of the ZrN lower barrier layer 12 into the wiring shape is completed, in order to generate the remaining portion of the ZrN etching mask 20 functioning as the ZrN upper barrier layer 24, Z before the start of etching is used.
The thickness T _E of the rN etching mask 20 may be set so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of wiring main material layer 14] / [etching rate of wiring main material layer 14] + [thickness of lower barrier layer 12] / [ Etching Rate of Lower Barrier Layer 12]} According to this example, the following advantages can be obtained.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Secondly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of ZrN, the thermal expansion coefficient of these barrier layers 12, 24 and 22 and the thermal expansion of the Cu wiring main material layer 14 are made. The difference from the coefficient can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of ZrN, these barrier layers 12, 24 and 22 have conductivity. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

[0104] In the fourth embodiment of the present invention defined in claim 1] This embodiment, except using N _{2 O} addition to the N ₂ as nitrogen-based gas of the etching gas, a third embodiment of the invention of claim 1 Similarly, ZrON is deposited as the sidewall barrier layer 22. ZrON has the effect of suppressing the diffusion of Cu to the same extent as ZrN.

In this embodiment, the sidewall barrier layer 22
ZrCl ₄ during etching to deposit
The gas flow rates of Cl ₂ , N ₂ and N ₂ O are respectively 20S.
CCM, 10 SCCM, 115 SCCM and 5 SCCM
Then, [Zr], [Cl] and [N] are as follows.

The number of Zr elements and the number of Cl elements contained in ZrCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Zr element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
204 × 10 ²⁴ , and the number of N elements contained in N ₂ O per unit volume at 0 ° C. and 1 atmospheric pressure is 6.02 × 1.
It becomes 0 ²³ × 2 = 1.204 × 10 ²⁴ pieces.

Therefore, the gas flow rate of ZrCl ₄ ; 20SCC
M, Cl ₂ gas flow rate; 10 SCCM, N ₂ gas flow rate; 115 SCCM, N ₂ O gas flow rate; 5 SCCM per unit time at 0 ° C. and 1 atmosphere (here, 1
The number of each element flowing into the etching chamber per minute is [Zr] = 6.02 × 10 ²³ × (20/100)
0) = 1.2 × 10 ²² pieces, [Cl] = 2.408 × 1
0 ²⁴ × (20/1000) + 1.204 × 10 ²⁴ ×
(10/1000) = 6.02 × 10 ²² , [N] =
1.204 x 10 ²⁴ x (115/1000) + 1.2
04 x 10 ²⁴ x (5/1000) = 1.44 x 10
²³ . The etching gas is ZrCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and N ₂ O is used, these Zr
The ratio [N] / [Cl] and the ratio [Zr] / [Cl] can be independently controlled by adjusting the gas flow rates of Cl ₄ , Cl ₂ , N ₂ and N ₂ O, respectively.
Further, the oxygen content of the ZrON side wall barrier layer 22 can be controlled while the desired number of [N] can be controlled by adjusting the gas flow rates of N ₂ and N ₂ O arbitrarily and appropriately.

The following effects can be expected in this embodiment as well.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, since the lower barrier layer 12 and the upper barrier layer 24 are made of ZrN and the side wall barrier layer 22 is made of ZrON, the thermal expansion coefficients of these barrier layers 12, 24 and 22 and the Cu wiring main material layer 14 are made. The difference from the coefficient of thermal expansion can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12 and the upper barrier layer 24 are made of ZrN and the side wall barrier layer 22 is made of ZrON, these barrier layers 12, 24 and 22 are conductive. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

The invention of claim 1 is not limited to the above-mentioned embodiment, and therefore various modifications can be made.

For example, as (1-A) main source gas, T
One or both of i chloride and Zr chloride can be used. It is preferable to use TiCl ₄ as the Ti chloride and ZrCl ₄ as the Zr chloride.

As (1-B) etching mask,
Ti film, Zr film, compound film containing one of Ti and Zr,
Also, a single-layer film made of a kind of film selected from compound films containing both Ti and Zr can be used.
As the compound film containing one of Ti and Zr, TiN,
The compound film containing both TiON, ZrN or ZrON, Ti and Zr may be TiZr, TiZrN or Ti.
It is preferable to use ZrON.

For example, in the above-described first embodiment of the invention of claim 1, the etching mask 20 is the TiN single layer film, but instead of the TiN single layer film, the TiON single layer film is formed as the etching mask 20. Good. In this case, Ti
The ON sidewall barrier layer 22 can be formed, and TiON can be expected to have a Cu diffusion suppression effect equal to or higher than that of TiN.

Although the etching mask 20 is the TiN single layer film in the second embodiment of the invention described above, the TiN single layer film may be replaced by a TiON single layer film, a ZrN single layer film or a ZrON single layer film. A single layer film may be formed as the etching mask 20. Etching mask 2 for TiON single layer film
When 0 is set, the TiON side wall barrier layer 22 can be formed. When the ZrN single layer film or the ZrON single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 is formed.
Can be formed. The effect of TiZrON to suppress Cu diffusion is T
It is considered to be equivalent to iN or TiON.

In the third embodiment of the invention of claim 1 described above, the etching mask 20 is a ZrN single layer film.
Instead of the ZrN single layer film, a ZrON single layer film, a TiN single layer film or a TiON single layer film may be formed as the etching mask 20. When the ZrON single layer film is used as the etching mask 20, the ZrON side wall barrier layer 22 can be formed. ZrO
The diffusion inhibiting effect of N on Cu is equal to or higher than that of ZrN. Further, when the TiON single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 can be formed,
When the N single layer film is used as the etching mask 20, TiZrN
The sidewall barrier layer 22 can be formed. TiZrON and Ti
The diffusion inhibiting effect of ZrN on Cu is TiN.
Or it is considered to be equivalent to TiON.

In the fourth embodiment of the invention of claim 1 described above, the etching mask 20 is a ZrN single layer film.
Instead of the ZrN single layer film, a ZrON single layer film, a TiN single layer film or a TiON single layer film may be formed as the etching mask 20. When the ZrON single layer film is used as the etching mask 20, the ZrON side wall barrier layer 22 can be formed. ZrO
N can be expected to have a diffusion suppressing effect equal to or higher than that of ZrN. Further, when the TiON single layer film or the TiN single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 can be formed. The diffusion inhibition effect of TiZrON on Cu is T
It is considered to be equivalent to iN or TiON.

Further, (1-C) Ti, Zr, TiN, Ti
ON, ZrN, ZrON, TiZr, TiZrN and T
iZrON has advantages of having conductivity, having a coefficient of thermal expansion close to that of Cu, and having an effect of suppressing diffusion and an effect of preventing oxidation of Cu, W, Ta, Al and other elements constituting the wiring main material layer. Have. Therefore, Ti, Zr, TiN, TiON, ZrN, ZrO is used as the lower barrier layer.
Forming N, TiZr, TiZrN or TiZrON,
Ti, Zr, TiN, TiON, Z as the upper barrier layer
rN, ZrON, TiZr, TiZrN or TiZrO
N is formed, and TiN, TiON, Z is used as a sidewall barrier layer.
rN, ZrON, TiZr, TiZrN or TiZrO
It is preferable to form N. As the wiring main material layer, C
u, W, Ta, Al or others can also be used.

Further, (1-D) NH ₃ may be contained as a nitrogen-based gas of the etching gas. In this case, since the chlorine content of the sidewall barrier layer can be reduced, it is possible to prevent chlorine from corroding the wiring material layer.

When the sidewall barrier layer containing (1-E) oxygen is deposited, the etching gas may contain an oxygen-based gas. One or both of O ₂ and O ₃ can be used as the oxygen-based gas. In this case, depending on the ratio of the number of oxygen elements and nitrogen elements contained in the etching gas, which are supplied to the etching chamber per unit time at 0 ° C. and 1 atmospheric pressure, the oxygen of the sidewall barrier layer containing oxygen is included. The content rate can be controlled. In the case of the side wall barrier layer containing oxygen, the Cu diffusion suppressing effect can be improved by controlling the oxygen content rate.

[First Embodiment of the Invention of Claim 5] In this embodiment, TiCl ₄ is used as a main source gas, Cl ₂ is used as a chlorine-based gas, and N ₂ and NH ₃ are used as a nitrogen-based gas.
The reactive etching gas is changed to TiCl ₄ , Cl ₂ ,
A mixed gas of N ₂ and NH ₃ is used. Therefore, the main source gas is a chloride containing Ti which is a constituent element of the sidewall barrier. A single layer film made of TiN is used as an etching mask. Therefore, the etching mask is a film containing Ti as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer and Main Wiring Material Layer Sequentially on Underlayer) First, in this embodiment, a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element are formed. Prepare a base 10 consisting of and
The TiN lower barrier layer 12 having a thickness of about 0.1 μm and Cu having a thickness of about 0.6 μm are sequentially deposited on the upper side by a sputtering method.
The wiring main material layer 14 is laminated (FIG. 1 (A) to FIG. 1).
(B)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
By the DC sputtering method with r, the TiN lower barrier layer 1
Stack two. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas.

(2: Step of forming an etching mask which also functions as an upper barrier layer on the wiring main material layer) Next, in this embodiment, a thickness of about 1.0 μm is formed on the Cu wiring main material layer 14 by the sputtering method. The TiN mask material 16 is laminated (FIG. 1C).

A semiconductor element such as MOSFET is formed on the base 10.
Even when the TiN lower barrier layer 12 is formed, according to a conventionally known thin film forming technique such as a sputtering method, the TiN lower barrier layer 12 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element.
The Cu wiring main material layer 14 and the TiN mask material 16 can be laminated.

The TiN lower barrier layer 12 and the TiN mask material 16 can be made of Ti _X N _1-X (0.5 ≦ X ≦ 1, for example X = 0.5).

Next, a resist is applied to the TiN mask material 16 to a thickness of 1 μm, and then the resist is exposed and developed to form a resist pattern 18 (FIG. 2).
(A)). The planar shape of the resist pattern 18 is a wiring shape.

Next, a conventionally known dry etching technique, here reactive ion etching (RIE: Reacti)
The TiN mask material 16 is etched into a wiring shape through the resist pattern 18 by a ve Ion Etching) method to form a TiN etching mask 20 made of this material 16 (FIG. 2B). The TiN etching mask 20 also serves as the upper barrier layer, and the portion remaining on the Cu wiring main material layer 14 after the deposition of the sidewall barrier layer described later functions as the upper barrier layer.

When forming the TiN etching mask 20, it is preferable to select the etching conditions so that the TiN mask material 16 is etched but the Cu wiring main material layer 14 is not etched. For example, in the case of reactive ion etching, the etching is performed with Cl ₂ as the reactive etching gas and room temperature as the base temperature,
The TiN mask material 16 can be etched so as not to etch the Cu wiring main material layer 14.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Then, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 3).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
By the reactive ion etching method using a mixed gas of TiCl ₄ , Cl ₂ , N ₂ and NH ₃ as the reactive etching gas, the Cu wiring main material layer 14 and the TiN lower barrier layer 12 are formed through the TiN etching mask 20. By sequentially etching, the main material layer 14 and the barrier layer 12 are processed into a wiring shape. During this etching process, TiCl ₄ , Cl
Reaction product T of the reactive etching gas, which is a mixed gas of ₂ , N ₂ and NH ₃ , and the TiN etching mask 20.
iN is the sidewall surface 20a of the TiN etching mask 20.
And the side wall surface 14a of the Cu wiring main material layer 14 which is etched
And the TiN sidewall barrier layer 22 deposited on the etching-processed sidewall surface 12a of the lower barrier layer 12 and thus consisting of this reaction product.
Can be deposited in a self-aligned manner. Also, the TiN lower barrier layer 1
After the etching process of No. 2, the TiN etching mask 20 remaining on the Cu wiring main material layer 14 functions as the TiN upper barrier layer 24. Therefore, it is processed into a wiring shape, and T
iN lower barrier layer 12, TiN upper barrier layer 24 and T
The Cu wiring main material layer 14 covered with the iN sidewall barrier layer 22 can be obtained (FIG. 3B).

Even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 and the TiN lower barrier layer are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. 12 can be etched and a TiN sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. A magnetron reactive ion etching device was used as an etching device, and the gas flow rates of TiCl ₄ , Cl ₂ , N ₂ and NH ₃ contained in the reactive etching gas were 20 SCCM, 10 SCCM and 112 SCCM, respectively.
And 17 SCCM, etching gas pressure 35 mTorr
r and RF power are set to 500W. The base temperature during etching is 25, which is suitable for etching the Cu wiring main material layer 14.
0 to 400 ° C. Here, the temperature is 300 ° C. Hereinafter, the etching conditions exemplified here will be referred to as etching conditions II.

In addition to variously changing the base temperature, when etching is performed under the above etching conditions (b),
FIG. 7 shows the relationship between the base temperature and the etching rate of Cu. The horizontal axis of FIG. 7 shows the base temperature [° C.], and the vertical axis shows the etching rate of Cu [nm / min]. The values obtained by measurement in the experiment are shown by plotting with white circles.

As can be understood from FIG. 7, in the range of the base temperature of 230 to 300 ° C., C increases as the base temperature increases.
The etching rate of u increases, and the base temperature becomes 30
When the temperature exceeds 0 ° C., the Cu etching rate becomes almost saturated (the etching rate becomes almost constant). In order to prevent deterioration of the characteristics of the semiconductor element formed on the underlayer 10 and increase the etching rate of Cu, it is preferable to set the underlayer temperature low. Therefore, the underlayer temperature is set to about 300 ° C. at which the saturation of the etching rate begins. It turns out that it is better to set the temperature.

Further, Ti element and Cl contained in the etching gas
The total number of Ti elements, the total number of Cl elements, and the total number of N elements, which are elements and N elements and are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atmospheric pressure, are [Ti], Expressing [Cl] and [N], the side etching amount of the Cu wiring main material layer 14 at the time of depositing the TiN side wall barrier layer 22 is represented by the ratio [N] / [C].
1] and the sidewall barrier layer 22.
Can be controlled according to the magnitude of the ratio [Ti] / [Cl].

The etching gas is TiCl ₄ , Cl ₂ , N
₂ and NH ₃ mixed gas, and TiCl ₄ and C during etching for depositing the sidewall barrier layer 22.
The gas flow rates of l ₂ , N ₂ and NH ₃ were respectively 20 SC
CM, 10 SCCM and 112 SCCM and 17 SCC
When M, [Ti], [Cl] and [N] are as follows.

The number of Ti elements and the number of Cl elements contained in TiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ x1 = 6.02 × 10 ²³ Ti element, Cl
Regarding the element 6.02 × 10 ²³ × 4 = 2.408 × 1
It becomes 0 ²⁴ . Similarly, at 0 ° C. and 1 atm, the number of Cl elements contained in Cl ₂ per unit volume is 6.02 × 1.
^{0 23 × 2 = 1.204 × 10} 24 pieces, 0 ° C., the number of N _{elements N 2} contains per unit volume in 1 atm 6.
02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ , and N contained in NH ₃ per unit volume at 0 ° C. and 1 atm.
The number of elements is 6.02 × 10 ²³ × 1 = 6.02 × 10
²³ .

Therefore, TiCl ₄ gas flow rate: 20 SCC
Gas flow rate of M and Cl ₂ ; 10 SCCM, gas flow rate of N ₂ ; 112 SCCM, gas flow rate of NH ₃ ; 17 SCCM
At 0 ° C. and 1 atmosphere, the number of each element flowing into the etching chamber per unit time (here, per minute) is [Ti] = 6.02 × 10 ²³ × (20/100
0) = 1.2 × 10 ²² pieces, [Cl] = 2.408 × 1
0 ²⁴ × (20/1000) + 1.204 × 10 ²⁴ ×
(10/1000) = 6.02 × 10 ²² , [N] =
1.204 x 10 ²⁴ x (112/1000) + 6.0
2 × 10 ²³ × (17/1000) = 1.45 × 10
²³ . The etching gas is TiCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and NH ₃ is used, these Ti
The ratio [N] / [Cl] and the ratio [Ti] / [Cl] can be independently controlled by adjusting the gas flow rates of Cl ₄ , Cl ₂ , N ₂ and NH ₃ arbitrarily and appropriately.

NH ₃ is the main source gas, that is, TiC.
It has the effect of reducing the Cl content of l TiN sidewall barrier layer 22 which is accelerated by thus depositing the dissociation of _4. Therefore, by appropriately adjusting the gas flow rates of N ₂ and NH ₃ , the Cl content of the TiN sidewall barrier layer 22 can be decreased while the desired number of [N] is obtained.

FIG. 8 is a diagram showing the relationship between the ratio [N] / [Cl] and the side etching amount of the wiring main material layer. In the figure, Ti is formed on the underlayer 10 in the same manner as the above-mentioned embodiment.
The N lower barrier layer 12, the Cu wiring main material layer 14 and the TiN mask material 16 are laminated, and a SiO ₂ etching mask is further formed on the TiN mask material 16. Then, when the TiN mask material 16 is etched through the SiO ₂ etching mask by the reactive ion etching method,
The side etching amount of the Cu wiring main material layer 14 is experimentally examined. During this etching, the gas flow rates of the nitrogen-based gases N ₂ and NH ₃ contained in the etching gas are changed to [N] /
An experiment was conducted in the same manner as in the above etching condition b except that [Cl] was changed variously, and the experiment result was
The horizontal axis of the figure shows the ratio [N] / [Cl], and the vertical axis shows the side etching amount [μm]. The values obtained by measurement in the experiment are shown by plotting with white circles.

As can be understood from FIG. 8, the ratio [N] /
As [Cl] increases, the side etching amount of the Cu wiring main material layer 14 decreases, and when [N] / [Cl] exceeds about 2, the side etching amount is almost zero, that is, the side etching of the Cu wiring main material layer 14 is performed. Can be understood to disappear.

Therefore, in order to prevent the side etching of the Cu wiring main material layer 14, it is preferable that [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> 0. Recognize.

Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
Side etching can be prevented, and the side wall barrier layer 2
Since the etching of the side wall barrier layer 22 is stopped at the deposition position of 2, the overetching of the Cu wiring main material layer 14 can be prevented or the amount of the overetching can be reduced, so that the Cu wiring main material layer 14 can be wired without trouble. Can be processed into a shape.

FIG. 9 is a diagram showing the relationship between the ratio [Ti] / [Cl] and the thickness of the sidewall barrier layer. In the figure, similar to the above-described embodiment, the TiN lower barrier layer 12, the Cu wiring main material layer 14, and the TiN mask material 16 are laminated on the underlayer 10, and then the TiN etching mask 20 is formed. To form. Then, by the reactive ion etching method, T
TiN mask material 16 through the iN etching mask 20
The thickness of the TiN sidewall barrier layer 22 in the case of etching was investigated experimentally. At the time of this etching, [NH ₃ gas flow rate] / {2 × [N ₂ gas flow rate] + [NH ₃ gas flow rate]} × 100 = 7%, and the gas flow rate of the main source gas TiCl ₄ contained in the etching gas By changing [Ti] /
Except that [Cl] is variously changed, the experimental results obtained when the experiment is performed in the same manner as the etching condition b described above are plotted by black triangles. Further, [NH ₃ gas flow rate] / {2 × [N ₂ gas flow rate] + [NH ₃ gas flow rate]} × 100 = 10% is set, and the gas flow rate of the main source gas TiCl ₄ contained in the etching gas is changed. [Ti] /
Except that [Cl] is variously changed, the experimental results obtained when the experiment is performed in the same manner as the etching condition b described above are plotted by black circles. Further, an experiment was conducted in the same manner as in the etching condition B described above except that [NH ₃ gas flow rate] / {2 × [N ₂ gas flow rate] + [NH ₃ gas flow rate]} × 100 = 15%. The experimental results in the case of being shown are plotted by white circles. The ratio [T
i] / [Cl] and the ordinate represents the thickness of the sidewall barrier layer 22 (thickness in the direction along the base surface) [nm].

As can be understood from FIG. 6, [Ti] / [when [NH ₃ gas flow rate] / {2 × [N ₂ gas flow rate] + [NH ₃ gas flow rate]} × 100 = 7% By setting Cl] to about 0.2, the thickness of the sidewall barrier layer 22 can be set to about 70 nm.

Therefore, by setting [Ti] / [Cl] = 0.2, the side wall barrier layer 22 having a thickness of 70 nm can be formed, and this thickness prevents oxidation of the Cu wiring main material layer 14 and diffusion of Cu. It is thick enough to prevent.

Further, at the time when the etching of the TiN lower barrier layer 12 into the wiring shape is completed, in order to generate the remaining portion of the TiN etching mask 20 functioning as the TiN upper barrier layer 24, T before the etching is started.
The thickness T _E of the iN etching mask 20 may be set so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of wiring main material layer 14] / [etching rate of wiring main material layer 14] + [thickness of lower barrier layer 12] / [ Etching Rate of Lower Barrier Layer 12]} According to this example, the following advantages can be obtained.

First, even if a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Secondly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of TiN, the thermal expansion coefficient of these TiN barrier layers 12, 24 and 22 and the heat of the Cu wiring main material layer 14 are increased. The difference from the expansion coefficient can be reduced. Therefore, these barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of TiN, these barrier layers 12, 24 and 22 have conductivity. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

Fourth, since at least NH ₃ is used as the nitrogen-based gas of the etching gas, the Cl content of the sidewall barrier layer 22 can be reduced. Since Cl causes corrosion of the Cu wiring main material layer 14, it is possible to prevent corrosion of the Cu wiring main material layer 14 by reducing the Cl content.

[Second Embodiment of the Invention of Claim 5] In this embodiment, N ₂ and N are used as the nitrogen-based gas of the etching gas.
TiON is deposited as the sidewall barrier layer 22 in the same manner as in the first embodiment of the invention of claim 5 described above except that N ₂ O is used in addition to H ₃ . TiON has the effect of suppressing the diffusion of Cu to the same extent as TiN or more.

In this example, TiCl ₄ , C during etching for depositing the sidewall barrier layer 22 was used.
The gas flow rates of l ₂ , N ₂ , NH ₃ and N ₂ O, respectively,
20SCCM, 10SCCM, 102SCCM, 16S
In the case of CCM and 10 SCCM, [Ti], [C
l] and [N] are as follows.

The number of Ti elements and the number of Cl elements contained in TiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ x1 = 6.02 × 10 ²³ Ti element, Cl
Regarding the element 6.02 × 10 ²³ × 4 = 2.408 × 1
It becomes 0 ²⁴ . Similarly, at 0 ° C. and 1 atm, the number of Cl elements contained in Cl ₂ per unit volume is 6.02 × 1.
^{0 23 × 2 = 1.204 × 10} 24 pieces, 0 ° C., the number of N _{elements N 2} contains per unit volume in 1 atm 6.
02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ pieces, 0 ° C.,
N contained in NH ₃ per unit volume at 0 ° C. and 1 atm
The number of elements is 6.02 × 10 ²³ × 1 = 6.02 × 10
²³ , and the number of N elements contained in N ₂ O per unit volume at 0 ° C. and 1 atmospheric pressure is 6.02 × 10 ²³ × 2 =
The number is 1.204 × 10 ²⁴ .

Therefore, TiCl ₄ gas flow rate: 20 SCC
Gas flow rate of M and Cl ₂ ; 10 SCCM and N ₂ gas flow rate; 102 SCCM and NH ₃ gas flow rate; 16 SCC
Gas flow rates of M and N ₂ O; the number of each element flowing into the etching chamber per unit time (here, per minute) at 0 ° C. and 1 atmospheric pressure at 10 SCCM is [Ti] =
6.02 × 10 ²³ × (20/1000) = 1.2 × 1
0 ²² pieces, [Cl] = 2.408 × 10 ²⁴ × (20 /
1000) + 1.204 × 10 ²⁴ × (10/100
0) = 6.02 × 10 ²² pieces, [N] = 1.204 × 1
0 ²⁴ × (102/1000) + 6.02 × 10 ²³ ×
(16/1000) + 1.204 × 10 ²⁴ × (10 /
1000) = 1.44 × 10 ²³ pieces. Since the etching gas is a mixed gas of TiCl ₄ , Cl ₂ , N ₂ , NH ₃ and N ₂ O, these TiCl ₄ , Cl ₂ ,
The ratio [N] / [Cl] and the ratio [T] can be adjusted by appropriately adjusting the gas flow rates of N ₂ , NH ₃ and N ₂ O, respectively.
i] / [Cl] can be controlled independently. Also N
By adjusting the gas flow rates of ₂ , ₂ , NH _3, and N ₂ O arbitrarily and appropriately, TiON can be obtained with a desired number of [N].
The chlorine content of the sidewall barrier layer 22 is reduced and TiON
It is also possible to control the oxygen content of the sidewall barrier layer 22.

Also in this embodiment, the following effects can be expected.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Secondly, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, the thermal expansion coefficients of these barrier layers 12, 24 and 22 and the Cu wiring main material layer 14 are made. The difference from the coefficient of thermal expansion can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, the barrier layers 12, 24 and 22 are conductive. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

Fourthly, since at least NH ₃ is used as the nitrogen gas of the etching gas, the Cl content of the side wall barrier layer 22 can be reduced, and therefore the corrosion of the Cu wiring main material layer 14 can be made less likely to occur.

[Third Embodiment of the Invention of Claim 5] In this embodiment, ZrCl ₄ is used as the main source gas, Cl ₂ is used as the chlorine-based gas, and N ₂ and NH ₃ are used as the nitrogen-based gas.
The reactive etching gas is changed to ZrCl ₄ , Cl ₂ ,
A mixed gas of N ₂ and NH ₃ is used. Therefore, the main source gas is a chloride containing Zr which is a sidewall barrier constituent element. A single layer film made of ZrN is used as an etching mask. Therefore, the etching mask is a film containing Zr as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer and Wiring Main Material Layer Sequentially on Underlayer) First, in this embodiment, a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element are formed. Prepare a base 10 consisting of and
The ZrN lower barrier layer 12 having a thickness of about 0.1 μm and Cu having a thickness of about 0.6 μm are sequentially deposited on the upper side by a sputtering method.
The wiring main material layer 14 is laminated (FIG. 1 (A) to FIG. 1).
(B)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
ZrN lower barrier layer 1 by DC sputtering method with r
Stack two. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas.

(2: Step of forming an etching mask which also functions as an upper barrier layer on the wiring main material layer) Next, in this embodiment, a thickness of about 1.0 μm is formed on the Cu wiring main material layer 14 by the sputtering method. The ZrN mask material 16 is laminated (FIG. 1 (C)).

A semiconductor element such as MOSFET is formed on the base 10.
Even when the ZrN lower barrier layer 12 is formed by a well-known thin film forming technique such as a sputtering method, the ZrN lower barrier layer 12 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element.
The Cu wiring main material layer 14 and the ZrN mask material 16 can be laminated.

The ZrN lower barrier layer 12 and the ZrN mask material 16 may be Zr _X N _1-X (0.5 ≦ X ≦ 1, for example X = 0.5).

Next, a resist is applied to the ZrN mask material 16 to a thickness of 1 μm, and then the resist is exposed and developed to form a resist pattern 18 (FIG. 2).
(A)). The planar shape of the resist pattern 18 is a wiring shape.

Next, a conventionally well-known dry etching technique, reactive ion etching (RIE: Reacti) is used here.
The ZrN mask material 16 is etched into a wiring shape through the resist pattern 18 by the ve Ion Etching) method to form a ZrN etching mask 20 made of this material 16 (FIG. 2B). The ZrN etching mask 20 also serves as the upper barrier layer, and the portion remaining on the Cu wiring main material layer 14 after the completion of the deposition of the sidewall barrier layer described later functions as the upper barrier layer.

When forming the ZrN etching mask 20, it is preferable to select etching conditions so that the ZrN mask material 16 is etched but the Cu wiring main material layer 14 is not etched. For example, in the case of reactive ion etching, the etching is performed with Cl ₂ as the reactive etching gas and room temperature as the base temperature,
The ZrN mask material 16 can be etched so as not to etch the Cu wiring main material layer 14.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. Can be formed.

Then, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 3).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
The Cu wiring main material layer 14 and the ZrN lower barrier layer 12 are formed through the ZrN etching mask 20 by a reactive ion etching method using a mixed gas of ZrCl ₄ , Cl ₂ , N ₂ and NH ₃ as a reactive etching gas. By sequentially etching, the main material layer 14 and the barrier layer 12 are processed into a wiring shape. During this etching process, ZrCl ₄ , Cl
Reaction product Z of the reactive etching gas, which is a mixed gas of ₂ , N ₂ and NH ₃ , and the ZrN etching mask 20.
rN is the side wall surface 20a of the ZrN etching mask 20.
And the side wall surface 14a of the Cu wiring main material layer 14 which is etched
And the ZrN sidewall barrier layer 22 which is deposited on the etching-processed sidewall surface 12a of the lower barrier layer 12 and which is formed by this reaction product, is formed on the sidewall surfaces 20a, 14a and 12a.
Can be deposited in a self-aligned manner. After the ZrN lower barrier layer 12 is etched, the ZrN etching mask 20 remaining on the Cu wiring main material layer 14 is ZrN.
It functions as the N upper barrier layer 24. Therefore, the Cu wiring main material layer 14 processed into the wiring shape and covered with the ZrN lower barrier layer 12, the ZrN upper barrier layer 24, and the ZrN side wall barrier layer 22 can be obtained (FIG. 3B).

Even when the semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 and the ZrN lower barrier layer are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. 12 can be etched and a ZrN sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. A magnetron reactive ion etching device was used as an etching device, and the gas flow rates of ZrCl ₄ , Cl ₂ , N ₂ and NH ₃ contained in the reactive etching gas were 20 SCCM, 10 SCCM and 112 SCCM, respectively.
And 17 SCCM, etching gas pressure 35 mTorr
r and RF power are set to 500W. The base temperature at the time of etching is 250 to 250, which is suitable for etching the Cu wiring main material layer 14.
400 ° C. Here, it is set to 300 ° C.

In this embodiment, ZrC is used as the main raw material gas.
Etching is performed using l ₄ to deposit the ZrN side wall barrier layer 22, and the reaction mechanism of this etching is the same as that of the first embodiment of the invention of claim 5 in which TiCl ₄ is used as the main source gas. Therefore, even in this example using ZrCl ₄ as the main raw material gas, it is considered that the relationship between the base temperature and the etching rate of Cu shows the same tendency as in FIG. 7. Therefore, in order to prevent deterioration of the characteristics of the semiconductor element formed on the underlayer 10 and increase the Cu etching rate, it is preferable to set the underlayer temperature at about 300 ° C. at which saturation of the Cu etching rate begins.

Zr element and Cl contained in the etching gas
[Zr], the total number of Zr elements, the total number of Cl elements, and the total number of N elements, which are elements and N elements and are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atm, respectively. Expressing [Cl] and [N], the side etching amount of the Cu wiring main material layer 14 at the time of depositing the ZrN side wall barrier layer 22 is expressed by the ratio [N] / [C].
1] and the sidewall barrier layer 22.
Can be controlled according to the magnitude of the ratio [Zr] / [Cl].

The etching gas is ZrCl ₄ , Cl ₂ , N
₂ and NH _{3 as} a mixed gas, and ZrCl ₄ and C at the time of etching for depositing the sidewall barrier layer 22.
The gas flow rates of l ₂ , N ₂ and NH ₃ were respectively 20 SC
CM, 10 SCCM, 112 SCCM and 17 SCCM
Then, [Zr], [Cl] and [N] are as follows.

The number of Zr elements and the number of Cl elements contained in ZrCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmosphere are Avogadro's number of 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Zr element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
204 × 10 ²⁴ , and the number of N elements contained in NH ₃ per unit volume at 0 ° C. and 1 atmospheric pressure is 6.02 × 1.
It becomes 0 ²³ × 1 = 6.02 × 10 ²³ pieces.

Therefore, the gas flow rate of ZrCl ₄ ; 20SCC
Gas flow rate of M and Cl ₂ ; 10 SCCM, gas flow rate of N ₂ ; 112 SCCM, gas flow rate of NH ₃ ; 17 SCCM
At 0 ° C. and 1 atmosphere, the number of each element flowing into the etching chamber per unit time (here, per minute) is [Zr] = 6.02 × 10 ²³ × (20/100
0) = 1.2 × 10 ²² pieces, [Cl] = 2.408 × 1
0 ²⁴ × (20/1000) + 1.204 × 10 ²⁴ ×
(10/1000) = 6.02 × 10 ²² , [N] =
1.204 x 10 ²⁴ x (112/1000) + 6.0
2 × 10 ²³ × (17/1000) = 1.45 × 10
²³ . The etching gas is ZrCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and NH ₃ is used, these Zr
The ratio [N] / [Cl] and the ratio [Zr] / [Cl] can be independently controlled by adjusting the gas flow rates of Cl ₄ , Cl ₂ , N ₂ and NH ₃ arbitrarily and appropriately.

NH ₃ is the main source gas, that is, ZrC.
It has the effect of reducing the Cl content of l ZrN sidewall barrier layer 22 which is accelerated by thus depositing the dissociation of _4. Therefore, by appropriately adjusting the gas flow rates of N ₂ and NH ₃ , it is possible to reduce the Cl content of the ZrN sidewall barrier layer 22 while maintaining the desired number of [N].

In this embodiment, ZrC is used as the main raw material gas.
Etching for depositing the ZrN side wall barrier layer 22 is performed using l _4, and the reaction mechanism of this etching is the same as that of the first embodiment of the invention of claim 5 in which TiCl ₄ is used as the main source gas. it is conceivable that. Therefore, also in this example using ZrCl ₄ as the main source gas, Cu
Side etching amount of wiring main material layer 14 and ratio [N] / [C]
1] shows the same relationship as in FIG. 8, and the relationship between the thickness of the sidewall barrier layer 22 and the ratio [Zr] / [Cl] is as follows.
It is considered that this shows the same relationship as in FIG.

Therefore, in order to prevent the side etching of the Cu wiring main material layer 14, it is preferable that [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> 0. To be Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
It is considered that the side etching of the Cu wiring main material layer 14 is prevented or the progress of the etching of the side wall barrier layer 22 is stopped at the deposition portion of the side wall barrier layer 22. Therefore, the Cu wiring main material layer 14 can be processed into a wiring shape without any trouble.

By setting [Zr] / [Cl] = 0.2, it is considered that the ZrN side wall barrier layer 22 having a thickness of 70 nm can be formed. This thickness is determined by oxidation of the Cu wiring main material layer 14 and Cu. Is thick enough to prevent the diffusion of

When the etching of the ZrN lower barrier layer 12 into the wiring shape is completed, the ZrN etching mask 20 functioning as the ZrN upper barrier layer 24 is left in order to form the remaining portion of the ZrN etching mask 20.
The thickness T _E of the rN etching mask 20 may be set so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of wiring main material layer 14] / [etching rate of wiring main material layer 14] + [thickness of lower barrier layer 12] / [ Etching Rate of Lower Barrier Layer 12]} According to this example, the following advantages can be obtained.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Secondly, since the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22 are made of ZrN, the thermal expansion coefficient of these barrier layers 12, 24 and 22 and the thermal expansion of the Cu wiring main material layer 14 are made. The difference from the coefficient can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12, the upper barrier layer 24 and the side wall barrier layer 22 are made of ZrN, these barrier layers 12, 24 and 22 have conductivity. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

Fourthly, since at least NH ₃ is used as the nitrogen gas of the etching gas, the Cl content of the side wall barrier layer 22 can be reduced, and therefore the corrosion of the Cu wiring main material layer 14 can be suppressed.

[Fourth Embodiment of the Invention of Claim 5] In this embodiment, N ₂ and N are used as the nitrogen-based gas of the etching gas.
ZrON is deposited as the sidewall barrier layer 22 in the same manner as in the third embodiment of the invention of claim 5 described above except that N ₂ O is used in addition to H ₃ . ZrON has the effect of suppressing the diffusion of Cu to the same extent as ZrN.

In this embodiment, the sidewall barrier layer 22 is formed.
ZrCl ₄ during etching to deposit
The gas flow rates of Cl ₂ , N ₂ , NH ₃ and N ₂ O are 20 SCCM, 10 SCCM, 102 SCCM and 1, respectively.
In the case of 6 SCCM and 10 SCCM, [Zr],
[Cl] and [N] are as follows.

The number of Zr elements and the number of Cl elements contained in ZrCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Zr element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
The number of N elements contained in NH ₃ per unit volume at 0 ° C. and 1 atmospheric pressure is 204 × 10 ^{24 and} 6.02 × 10 ²³
The number of N elements contained in N ₂ O per unit volume at 0 ° C. and 1 atmospheric pressure was 6. × 1 = 6.02 × 10 ²³ pieces.
It becomes 02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ pieces.

Therefore, the gas flow rate of ZrCl ₄ ; 20SCC
Gas flow rate of M and Cl ₂ ; 10 SCCM and N ₂ gas flow rate; 102 SCCM and NH ₃ gas flow rate; 16 SCC
Gas flow rates of M and N ₂ O; the number of each element flowing into the etching chamber per unit time (here, per minute) at 0 ° C. and 1 atmospheric pressure at 10 SCCM is [Ti] =
6.02 × 10 ²³ × (20/1000) = 1.2 × 1
0 ²² pieces, [Cl] = 2.408 × 10 ²⁴ × (20 /
1000) + 1.204 × 10 ²⁴ × (10/100
0) = 6.02 × 10 ²² pieces, [N] = 1.204 × 1
0 ²⁴ × (102/1000) + 6.02 × 10 ²³ ×
(16/1000) + 1.204 × 10 ²⁴ × (10 /
1000) = 1.44 × 10 ²³ pieces. Since the etching gas is a mixed gas of ZrCl ₄ , Cl ₂ , N ₂ , NH ₃ and N ₂ O, these ZrCl ₄ , Cl ₂ ,
The ratio [N] / [Cl] and the ratio [Z] can be adjusted by appropriately adjusting the gas flow rates of N ₂ , NH ₃ and N ₂ O, respectively.
r] / [Cl] can be controlled independently. Also N
By adjusting the gas flow rates of ₂ , ₂ , NH ₃ and N ₂ O arbitrarily and appropriately, the desired number of [N] can be obtained and ZrON
The Cl content of the side wall barrier layer 22 is reduced and ZrON
It is also possible to control the oxygen content of the sidewall barrier layer 22.

The following effects can be expected in this embodiment as well.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, since the lower barrier layer 12 and the upper barrier layer 24 are made of ZrN and the side wall barrier layer 22 is made of ZrON, the thermal expansion coefficients of these barrier layers 12, 24 and 22 and the Cu wiring main material layer 14 are made. The difference from the coefficient of thermal expansion can be reduced. Therefore, the barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12 and the upper barrier layer 24 are made of ZrN and the side wall barrier layer 22 is made of ZrON, these barrier layers 12, 24 and 22 are conductive. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

Fourthly, since at least NH ₃ is used as the nitrogen gas of the etching gas, the Cl content of the side wall barrier layer 22 can be reduced, and therefore the corrosion of the Cu wiring main material layer 14 can be made less likely to occur.

The invention of claim 5 is not limited to the above-mentioned embodiment, and various modifications can be made.

For example, as (2-A) main source gas, T
One or both of i chloride and Zr chloride can be used. It is preferable to use TiCl ₄ as the Ti chloride and ZrCl ₄ as the Zr chloride.

As a (2-B) etching mask,
Ti film, Zr film, compound film containing one of Ti and Zr,
Also, a single-layer film made of a kind of film selected from compound films containing both Ti and Zr can be used.
As the compound film containing one of Ti and Zr, TiN,
The compound film containing both TiON, ZrN or ZrON, Ti and Zr may be TiZr, TiZrN or Ti.
It is preferable to use ZrON.

For example, in the above-described first embodiment of the invention of claim 5, the etching mask 20 is a TiN single layer film, but instead of the TiN single layer film, a TiON single layer film, ZrN is used.
A single layer film or a ZrON single layer film may be formed as the etching mask 20. When the TiON single layer film is used as the etching mask 20, the TiON side wall barrier layer 22 can be formed, and TiON can be expected to have a Cu diffusion suppressing effect equivalent to or more than TiN. When the ZrN single layer film is used as the etching mask 20, the TiZrN sidewall barrier layer 22 can be formed, and ZrO
When the N monolayer film is used as the etching mask 20, TiZrO
The N sidewall barrier layer 22 can be formed. TiZrN and Ti
ZrON has Cu diffusion suppression effect of TiN or T, respectively.
It is considered to be equivalent to iON.

In the second embodiment of the invention of claim 5, the etching mask 20 is a TiN single layer film, but instead of the TiN single layer film, a TiON single layer film, a ZrN single layer film or a ZrON single layer film is used. A single layer film may be formed as the etching mask 20. Etching mask 2 for TiON single layer film
When 0 is set, the TiON side wall barrier layer 22 can be formed. When the ZrN single layer film or the ZrON single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 is formed.
Can be formed. The effect of TiZrON to suppress Cu diffusion is T
It is considered to be equivalent to iN or TiON.

In the third embodiment of the fifth aspect of the invention described above, the etching mask 20 is a ZrN single layer film.
Instead of the ZrN single layer film, a ZrON single layer film, a TiN single layer film or a TiON single layer film may be formed as the etching mask 20. When the ZrON single layer film is used as the etching mask 20, the ZrON side wall barrier layer 22 can be formed. ZrO
The diffusion inhibiting effect of N on Cu is equal to or higher than that of ZrN. Further, when the TiON single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 can be formed,
When the N single layer film is used as the etching mask 20, TiZrN
The sidewall barrier layer 22 can be formed. TiZrON and Ti
The diffusion inhibiting effect of ZrN on Cu is TiN.
Or it is considered to be equivalent to TiON.

In the fourth embodiment of the invention of claim 5 described above, the etching mask 20 is a ZrN single layer film.
Instead of the ZrN single layer film, a ZrON single layer film, a TiN single layer film or a TiON single layer film may be formed as the etching mask 20. When the ZrON single layer film is used as the etching mask 20, the ZrON side wall barrier layer 22 can be formed. ZrO
N can be expected to have a diffusion suppressing effect equal to or higher than that of ZrN. Further, when the TiON single layer film or the TiN single layer film is used as the etching mask 20, the TiZrON side wall barrier layer 22 can be formed. The diffusion inhibition effect of TiZrON on Cu is T
It is considered to be equivalent to iN or TiON.

Further, (2-C) Ti, Zr, TiN, Ti
ON, ZrN, ZrON, TiZr, TiZrN and T
iZrON has advantages of having conductivity, having a coefficient of thermal expansion close to that of Cu, and having an effect of suppressing diffusion and an effect of preventing oxidation of Cu, W, Ta, Al and other elements constituting the wiring main material layer. Have. Therefore, Ti, Zr, TiN, TiON, ZrN, ZrO is used as the lower barrier layer.
Forming N, TiZr, TiZrN or TiZrON,
Ti, Zr, TiN, TiON, Z as the upper barrier layer
rN, ZrON, TiZr, TiZrN or TiZrO
N is formed, and TiN, TiON, Z is used as a sidewall barrier layer.
rN, ZrON, TiZr, TiZrN or TiZrO
It is preferable to form N. As the wiring main material layer, C
u, W, Ta, Al or others can also be used.

(2-D) SiCl as the main source gas
No. ₄ , using a SiN single layer film or S as an etching mask
An iON single layer film may be used.

When the sidewall barrier layer containing (2-E) oxygen is deposited, the etching gas may contain an oxygen-based gas. One or both of O ₂ and O ₃ can be used as the oxygen-based gas. In this case, depending on the ratio of the number of oxygen elements and nitrogen elements contained in the etching gas, which are supplied to the etching chamber per unit time at 0 ° C. and 1 atmospheric pressure, the oxygen of the sidewall barrier layer containing oxygen is included. The content rate can be controlled. In the case of the side wall barrier layer containing oxygen, the Cu diffusion suppressing effect can be improved by controlling the oxygen content rate.

10 to 12 are process drawings for explaining the embodiment of the invention of claim 16 and the invention of claim 21.
Embodiments of the present invention will be described below with reference to FIGS. The conditions for forming a thin film, materials to be used, processing temperature, processing time, film thickness, gas flow rate, and other conditions described below are merely examples, and therefore these conditions are not limited to those described below.

[Embodiment of the Invention of Claim 16] In this embodiment, SiCl ₄ is used as a main source gas, Cl ₂ is used as a chlorine-based gas, and N ₂ and NH ₃ are used as a nitrogen-based gas, and a reactive etching gas is used. These SiCl ₄ , Cl ₂ , N
A mixed gas of ₂ and NH ₃ . Therefore, the main source gas is a chloride containing Si, which is a sidewall barrier constituent element. A single layer film made of SiO ₂ is used as an etching mask. Therefore, the etching mask is a film containing Si as a sidewall barrier constituent element.

(1-1: The lower barrier layer is sequentially formed on the base,
Step of Laminating Main Wiring Material Layer and Upper Barrier Layer) First, in this embodiment, a base 10 including a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element is prepared. The TiN lower barrier layer 12 having a thickness of about 0.1 μm and the thickness of 0.
A Cu wiring main material layer 14 having a thickness of about 6 μm and a TiN upper barrier layer 24 having a thickness of 0.1 μm are stacked (FIGS. 10A to 10C).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
By the DC sputtering method with r, the TiN lower barrier layer 1
2 and the TiN upper barrier layer 24 are laminated. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas. The TiN lower barrier layer 12 and Ti
The N upper barrier layer 24 is formed of Ti _X N _1-X (0.5 ≦ X ≦
1, for example X = 0.5).

Even when a semiconductor element is formed on the underlayer 10, each of the layers 12, 14, 24 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element by a conventionally known thin film forming technique such as a sputtering method. Can be formed.

(1-2: Step of forming etching mask on upper barrier layer) Next, in this embodiment, plasma C is used.
VD (Chemical Vapor Deposition)
Ion) method is used to deposit a 0.6 μm thick SiO ₂ mask material 16 on the TiN upper barrier layer 24 (FIG. 1).
1 (A)).

For example, SiH ₄ and N ₂ as source gases
SiH ₄ gas flow rate of 80SCCM using O mixed gas
And N ₂ O gas flow rate 1900 SCCM, film formation chamber pressure 300 mTorr, base temperature 200 ° C. and rf power 2
The SiO ₂ mask material 16 is deposited as 00W.

Even when the semiconductor element is formed on the underlayer 10, the mask material 16 is deposited at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element by a conventionally known thin film forming technique such as plasma CVD. it can.

The SiO ₂ mask material 16 serves as an etching mask 20 for etching the TiN upper barrier layer 24, the Cu wiring material layer 14 and the TiN lower barrier layer 12 into wiring shapes. Therefore, the thickness T _E of the etching mask 20 is preferably determined so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of upper barrier layer 24] / [etching rate of upper barrier layer 24] + [thickness of main wiring layer 14] / [main wiring main] Material layer 14 etching rate] + [thickness of lower barrier layer 12] / [etching rate of lower barrier layer 12]} Next, a resist having a thickness of 1 μ is formed on the SiO ₂ mask material 16.
Then, the resist is exposed and developed to form a resist pattern 18 (FIG. 11B). The planar shape of the resist pattern 18 is a wiring shape.

Next, a heretofore known dry etching technique, here reactive ion etching (RIE: Reacti)
ve Ion Etching) method, the SiO ₂ mask material 16 is etched into a wiring shape through the resist pattern 18 to form a SiO ₂ etching mask 20 made of this material 16 (FIG. 11C).

When the SiO ₂ etching mask 20 is formed, the SiO ₂ mask material 16 is etched but TiN is used.
The etching conditions are preferably selected so that the upper barrier layer 24 is not etched. For example, in the case of reactive ion etching, the reactive etching gas is CHF.
By performing etching using a mixed gas of ₃ and O ₂ , the SiO ₂ mask material 16 can be etched without etching the TiN upper barrier layer 24.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Next, the resist pattern 18 is removed by an ashing process using O ₂ plasma (FIG. 12).
(A)).

(1-3: While etching the wiring main material layer into a wiring shape by the reactive ion etching method,
Step of depositing a side wall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas on the side wall surface of the wiring main material layer that is etched) Next, in this example, SiCl ₄ , Cl ₂ , N ₂ and N
The TiN upper barrier layer 24, the Cu wiring main material layer 14, and the TiN lower barrier layer 12 are sequentially formed through the SiO ₂ etching mask 20 by a reactive ion etching method using a mixed gas of H ₃ as a reactive etching gas. By etching, the barrier layer 24, the main material layer 14, and the barrier layer 12 are etched.
Is processed into a wiring shape. During this etching process, Si
The reaction product SiON of the reactive etching gas which is a mixed gas of Cl ₄ , Cl ₂ , N ₂ and NH ₃ and the SiO ₂ etching mask 20 is the SiO ₂ etching mask 2
0 side wall surface 20a, TiN upper barrier layer 24 etching side wall surface 24a, Cu wiring main material layer 14 etching side wall surface 14a, lower barrier layer 12 etching side wall surface 12a, Therefore, the SiON side wall barrier layer 22 composed of this reaction product is formed on the side wall surface 2
It can be self-aligned on 0a, 24a, 14a and 12a. Therefore, the Cu wiring main material layer 14 which is processed into the wiring shape and covered with the TiN lower barrier layer 12, the TiN upper barrier layer 24 and the SiON side wall barrier layer 22 can be obtained (FIG. 12B).

Even when the semiconductor element is formed on the underlayer 10, the TiN upper barrier layer 24 and the Cu wiring main material layer 14 are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. , TiN lower barrier layer 12 can be etched and a SiON sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. A magnetron reactive ion etching device was used as an etching device, and the gas flow rates of SiCl ₄ , Cl ₂ , N ₂ and NH ₃ contained in the reactive etching gas were 20 SCCM, 10 SCCM and 112 SCCM, respectively.
And 17 SCCM, etching gas pressure 35 mTorr
r and RF power are set to 500W. The base temperature during etching is 25, which is suitable for etching the Cu wiring main material layer 14.
0 to 400 ° C. Here, the temperature is 300 ° C.

The Si element, the Cl element and the N element contained in the etching gas, which are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atm.
If the total number of i elements, the total number of Cl elements, and the total number of N elements are expressed as [Si], [Cl], and [N], respectively,
When the SiON sidewall barrier layer 22 is deposited, the side etching amount of the Cu wiring main material layer 14 is defined as a ratio [N] / [Cl].
And the thickness of the sidewall barrier layer 22 can be controlled according to the ratio [Si] / [Cl].

The etching gas is SiCl ₄ , Cl ₂ , N
₂ and NH _{3 as} a mixed gas, and SiCl ₄ , C during etching for depositing the sidewall barrier layer 22
The gas flow rates of l ₂ , N ₂ and NH ₃ were respectively 20 SC
CM, 10 SCCM and 112 SCCM and 17 SCC
When M, [Si], [Cl] and [N] are as follows.

The number of Si elements and the number of Cl elements contained in SiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Si element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
204 × 10 ²⁴ , and the number of N elements contained in NH ₃ per unit volume at 0 ° C. and 1 atmospheric pressure is 6.02 × 1.
It becomes 0 ²³ × 1 = 6.02 × 10 ²³ pieces.

Accordingly, the gas flow rate of SiCl ₄ is 20 SCC.
Gas flow rate of M and Cl ₂ ; 10 SCCM, gas flow rate of N ₂ ; 112 SCCM, gas flow rate of NH ₃ ; 17 SCCM
At 0 ° C. and 1 atmosphere, the number of each element flowing into the etching chamber per unit time (here, per minute) is [Si] = 6.02 × 10 ²³ × (20/100
0) = 1.2 × 10 ²² pieces, [Cl] = 2.408 × 1
0 ²⁴ × (20/1000) + 1.204 × 10 ²⁴ ×
(10/1000) = 6.02 × 10 ²² , [N] =
1.204 x 10 ²⁴ x (112/1000) + 6.0
2 × 10 ²³ × (17/1000) = 1.45 × 10
²³ . The etching gas is SiCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and NH ₃ is used, these Si
The ratio [N] / [Cl] and the ratio [Si] / [Cl] can be controlled independently by adjusting the gas flow rates of Cl ₄ , Cl ₂ , N ₂ and NH ₃ arbitrarily and appropriately.

NH ₃ is the main source gas, that is, SiC.
It has the effect of reducing the Cl content of promoting dissociation of l ₄ thus deposited SiON sidewall barrier layer 22. Therefore, the Cl content of the SiON side wall barrier layer 22 can be reduced while adjusting [N] to a desired number by adjusting the gas flow rates of N ₂ and NH ₃ arbitrarily and suitably.

In order to prevent side etching of the Cu wiring main material layer 14, [N] / [Cl]> 2, that is, 0.
It is preferable that 5> [Cl] / [N]> 0. By controlling the ratio [N] / [Cl] or [Cl] / [N] in this way, side etching of the Cu wiring main material layer 14 can be prevented, and the sidewall barrier layer 22 is deposited at the sidewall barrier layer 22. Since the etching of 22 stops, Cu
Over-etching of the wiring main material layer 14 can be prevented or the amount of over-etching can be reduced, so that the Cu wiring main material layer 14 can be processed into a wiring shape without trouble.

By setting [Si] / [Cl] = 0.2, the sidewall barrier layer 22 having a thickness of about 70 nm can be formed, and this thickness can be obtained by oxidation of the Cu wiring main material layer 14 and Cu.
Is thick enough to prevent the diffusion of

According to this embodiment, the following advantages can be expected.

First, even if a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, the upper barrier layer 24 and the wiring main material layer 1
4 and the lower barrier layer 12 are etched into a wiring shape, the sidewall barrier layer 22 is sequentially deposited on the etched sidewall surface generated in the etching process. Therefore, even if thermal stress acts between the wiring main material layer 14 and the upper barrier layer 24 and the lower barrier layer 12, these barrier layers 24,
It is possible to prevent peeling of 12 from the wiring main material layer 14 due to thermal stress.

Thirdly, since at least NH ₃ is used as the nitrogen-based gas of the etching gas, the Cl content of the sidewall barrier layer 22 can be reduced. Since Cl causes corrosion of the Cu wiring main material layer 14, it is possible to prevent corrosion of the Cu wiring main material layer 14 by reducing the Cl content.

The invention of claim 16 is not limited to the above-described embodiment, and various modifications can be made.

For example, (3-A) SiC as the main raw material gas
When l ₄ is used, SiO is used as an etching mask.
₂ , a single layer film composed of one kind of film selected from SiN and SiON or a multilayer film composed of plural kinds of films may be used.

Further, as (3-B) main source gas, one or both of Ti chloride and Zr chloride can be used. It is preferable to use TiCl ₄ as the Ti chloride and ZrCl ₄ as the Zr chloride. in this case,
As an etching mask, Ti film, Zr film, Ti and Z
A single-layer film made of one kind of film selected from a compound film containing one of r and a compound film containing both Ti and Zr, or a multilayer film made of a plurality of kinds of films can be used. As the compound film containing one of Ti and Zr, T
It is preferable to use TiZr, TiZrN or TiZrON as the compound film containing both iN, TiON, ZrN or ZrON, Ti and Zr.

Further, (3-C) Ti, Zr, TiN, Ti
ON, ZrN, ZrON, TiZr, TiZrN and T
iZrON has advantages of having conductivity, having a coefficient of thermal expansion close to that of Cu, and having an effect of suppressing diffusion and an effect of preventing oxidation of Cu, W, Ta, Al and other elements constituting the wiring main material layer. Have. Therefore, Ti, Zr, TiN, TiON, ZrN, ZrO is used as the lower barrier layer.
Forming N, TiZr, TiZrN or TiZrON,
Ti, Zr, TiN, TiON, Z as the upper barrier layer
rN, ZrON, TiZr, TiZrN or TiZrO
N is formed, and TiN, TiON, Z is used as a sidewall barrier layer.
rN, ZrON, TiZr, TiZrN or TiZrO
It is preferable to form N. As the wiring main material layer, C
u, W, Ta, Al or others can also be used.

Further, in the case of depositing the sidewall barrier layer containing (3-D) oxygen, the etching gas may contain an oxygen-based gas. One or both of O ₂ and O ₃ can be used as the oxygen-based gas. In this case, the oxygen content of the sidewall barrier layer containing oxygen depends on the number of oxygen elements and nitrogen elements contained in the etching gas and is supplied to the etching chamber per unit time at 0 ° C. and 1 atmosphere. Can be controlled. In the case of the side wall barrier layer containing oxygen, the Cu diffusion suppressing effect can be improved by controlling the oxygen content rate.

As (3-E) nitrogen-based gas, NH ₃
In addition, one or both of N ₂ and N ₂ O may be used.

[0247] In the embodiment of the present invention defined in claim 21 This example, SiCl _4, and _{O 2} is used as _{N 2} and oxygen-containing gas as Cl ₂ and nitrogen-based gas as a chlorine-based gas as the main raw material gas, the reactive The etching gas is changed to these SiCl
A mixed gas of ₄ , Cl ₂ , N ₂ and O ₂ . Therefore, the main source gas is a chloride containing Si, which is a sidewall barrier constituent element. A single layer film made of SiO ₂ is used as an etching mask. Therefore, the etching mask is a film containing Si as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer, Wiring Main Material Layer and Upper Barrier Layer Sequentially on Underlayer) First, in this embodiment, a Si substrate on which a semiconductor element is formed and a semiconductor element are formed. A base 10 made of a SiO ₂ film is prepared, and a TiN lower barrier layer 12 having a thickness of about 0.1 μm and a thickness of 0.6 are sequentially formed on the base 10 by a sputtering method.
Cu wiring main material layer 14 having a thickness of about μm and T having a thickness of 0.1 μm
The iN upper barrier layer 24 is laminated (FIG. 10 (A) to FIG. 1).
0 (C)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
By the DC sputtering method with r, the TiN lower barrier layer 1
2 and the TiN upper barrier layer 24 are laminated. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas. The TiN lower barrier layer 12 and Ti
The N upper barrier layer 24 is formed of Ti _X N _1-X (0.5 ≦ X ≦
1, for example X = 0.5).

Even when a semiconductor element is formed on the underlayer 10, the layers 12, 14, 24 are formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element by a conventionally known thin film forming technique such as a sputtering method. Can be formed.

(2: Step of forming etching mask on upper barrier layer) Next, in this embodiment, plasma CVD is performed.
(Chemical Vapor Deposition
n) on the TiN upper barrier layer 24 to a thickness of 0.6.
A SiO ₂ mask material 16 of μm is laminated (FIG. 11).
(A)).

For example, SiH ₄ and N ₂ as source gases
SiH ₄ gas flow rate of 80SCCM using O mixed gas
And N ₂ O gas flow rate 1900 SCCM, film formation chamber pressure 300 mTorr, base temperature 200 ° C. and rf power 2
The SiO ₂ mask material 16 is deposited as 00W.

Even when the semiconductor element is formed on the underlayer 10, the mask material 16 is deposited at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element by a conventionally known thin film forming technique such as plasma CVD. it can.

Since the SiO ₂ mask material 16 serves as an etching mask 20 for etching the TiN upper barrier layer 24, the Cu wiring material layer 14 and the TiN lower barrier layer 12 into wiring shapes, the mask material 16 is used. Therefore, the thickness T _E of the etching mask 20 is preferably determined so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of upper barrier layer 24] / [etching rate of upper barrier layer 24] + [thickness of wiring main material layer 14] / [wiring main Material layer 14 etching rate] + [thickness of lower barrier layer 12] / [etching rate of lower barrier layer 12]} Next, a resist having a thickness of 1 μ is formed on the SiO ₂ mask material 16.
Then, the resist is exposed and developed to form a resist pattern 18 (FIG. 11B). The planar shape of the resist pattern 18 is a wiring shape.

Next, a heretofore known dry etching technique, here reactive ion etching (RIE: Reacti)
ve Ion Etching) method, the SiO ₂ mask material 16 is etched into a wiring shape through the resist pattern 18 to form a SiO ₂ etching mask 20 made of this material 16 (FIG. 11C).

When the SiO ₂ etching mask 20 is formed, the SiO ₂ mask material 16 is etched but TiN is used.
The etching conditions are preferably selected so that the upper barrier layer 24 is not etched. For example, in the case of reactive ion etching, the reactive etching gas is CHF.
By performing etching using a mixed gas of ₃ and O ₂ , the SiO ₂ mask material 16 can be etched without etching the TiN upper barrier layer 24.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Next, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 12).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
By a reactive ion etching method using a mixed gas of SiCl ₄ , Cl ₂ , N ₂ and O ₂ as a reactive etching gas, the TiN upper barrier layer 24, the Cu wiring main material layer 14 and the Cu wiring main material layer 14 are formed through the SiO ₂ etching mask 20. The TiN lower barrier layer 12 is sequentially etched to remove these barrier layers 24,
The main material layer 14 and the barrier layer 12 are processed into a wiring shape. During this etching process, a reactive etching gas, which is a mixed gas of SiCl ₄ , Cl ₂ , N ₂ and O ₂ , and SiO
₂ The reaction product SiON with the etching mask 20 is S
The sidewall surface 20a of the io ₂ etching mask 20 and TiN
An etching-processed sidewall surface 24a of the upper barrier layer 24, and C
The SiON side wall barrier layer 22 which is deposited on the etched side wall surface 14a of the u wiring main material layer 14 and the etched side wall surface 12a of the lower barrier layer 12 and therefore is formed by this reaction product is formed on the side wall surfaces 20a and 24a. , 14a and 1
2a can be deposited in a self-aligned manner. Accordingly, the TiN lower barrier layer 12 and the TiN upper barrier layer 2 are processed into a wiring shape.
4 and the Cu wiring main material layer 14 covered with the SiON side wall barrier layer 22 can be obtained (FIG. 12B).

Even when the semiconductor element is formed on the underlayer 10, the TiN upper barrier layer 24 and the Cu wiring main material layer 14 are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. , TiN lower barrier layer 12 can be etched and a SiON sidewall barrier layer 22 can be deposited.

The etching conditions may be set as follows, for example. Using a magnetron reactive ion etching device as an etching device, the gas flow rates of SiCl ₄ , Cl ₂ , N ₂ and O ₂ contained in the reactive etching gas are 20 SCCM, 10 SCCM, 120 SCCM and 5 SCCM, respectively, and the etching gas pressure is 35 mTorr, R
F power is set to 500W. Base temperature during etching is C
Temperature suitable for etching u wiring main material layer 14
00 ° C. Here, it is set to 300 ° C. Hereinafter, the etching conditions exemplified here will be referred to as etching conditions C.

In addition to variously changing the base temperature, when the etching is performed under the above-mentioned etching condition C,
FIG. 13 shows the relationship between the base temperature and the etching rate of Cu.
Shown in In FIG. 13, the horizontal axis represents the substrate temperature [° C.] and the vertical axis represents Cu.
The etching rate [nm / min] is shown. The values obtained by measurement in the experiment are shown by plotting with white circles.

As can be understood from FIG. 13, in the range of the base temperature of 230 to 300 ° C., the etching rate of Cu increases with the increase of the base temperature, and the base temperature becomes 3%.
When the temperature exceeds 00 ° C., the etching rate of Cu is almost saturated (the etching rate becomes almost constant). While preventing the characteristic deterioration of the semiconductor element formed on the underlayer 10, Cu
In order to increase the etching rate, it is preferable to set the base temperature low, and it is therefore preferable to set the base temperature at about 300 ° C. at which saturation of the etching rate begins.

Further, Si element contained in the etching gas, Cl
The total number of Si elements, the total number of Cl elements, the total number of N elements, and the total number of O elements which are elements and N elements and are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atm. [Si], [Cl],
When expressed as [N] and [O], the SiON sidewall barrier layer 22
The side etching amount of the Cu wiring main material layer 14 at the time of depositing can be controlled according to the size of the ratio [N] / [Cl], and the thickness of the sidewall barrier layer 22 can be controlled by the ratio [Si] / [Cl].
Of the wiring main material layer 14 and the oxidation of the wiring main material layer 14 can be controlled according to the size of the ratio [O] / [N].

The etching gas is SiCl ₄ , Cl ₂ , N
₂ and O _{2 as} a mixed gas, and SiCl ₄ , Cl ₂ at the time of etching for depositing the sidewall barrier layer 22,
The gas flow rates of N ₂ and O ₂ are 20 SCCM and 1 respectively.
With 0 SCCM, 120 SCCM and 5 SCCM, [Si], [Cl], [N] and [O] are as follows.

The number of Si elements and the number of Cl elements contained in SiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmosphere are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ x1 = 6.02 × 10 ²³ pieces of Si element, Cl
Regarding the element 6.02 × 10 ²³ × 4 = 2.408 × 1
It becomes 0 ²⁴ . Similarly, at 0 ° C. and 1 atm, the number of Cl elements contained in Cl ₂ per unit volume is 6.02 × 1.
^{0 23 × 2 = 1.204 × 10} 24 pieces, 0 ° C., the number of N _{elements N 2} contains per unit volume in 1 atm 6.
02 × 10 ²³ × 2 = 1.204 × 10 ²⁴ , and the number of O elements contained in O ₂ per unit volume at 0 ° C. and 1 atmosphere is 6.02 × 10 ²³ × 2 = 1.204 × 10.
It will be ²⁴ .

Therefore, the gas flow rate of SiCl ₄ is 20 SCC.
M, Cl ₂ gas flow rate; 10 SCCM, N ₂ gas flow rate; 120 SCCM, O ₂ gas flow rate; 5 SCCM, each element flowing into the etching chamber per unit time (here 1 minute) at 0 ° C. and 1 atmospheric pressure. The number of
[Si] = 6.02 × 10 ²³ × (20/1000) =
1.2 × 10 ²² pieces, [Cl] = 2.408 × 10 ²⁴
× (20/1000) + 1.204 × 10 ²⁴ × (10
/1000)=6.02×10 ²² pieces, [N] = 1.2
04 × 10 ²⁴ × (120/1000) = 1.44 × 1
0 ²³ , and further [O] = 1.204 × 10 ²⁴ × (5
/1000)=6.02×10 ²³ . Since the etching gas is a mixed gas of SiCl _{4, Cl 2, N} 2 and _{O 2,} by adjusting any suitably These SiCl _{4, Cl 2, N} 2 and _{O 2} gas flow rate, respectively, the ratio [N] / [Cl] and the ratio [Si] / [Cl] can be controlled independently.

FIG. 14 is a diagram showing the relationship between the ratio [N] / [Cl] and the side etching amount of the wiring main material layer. In the figure, as in the above-described embodiment, T is formed on the underlayer 10.
iN lower barrier layer 12, Cu wiring main material layer 14 and TiN
The upper barrier layer 24 is laminated, and a SiO ₂ etching mask is further formed on the TiN upper barrier layer 24. Then, the amount of side etching of the Cu wiring main material layer 14 when the TiN upper barrier layer 24 is etched through the SiO ₂ etching mask by the reactive ion etching method is experimentally examined. During this etching, the gas flow rate of the nitrogen-based gas N ₂ contained in the etching gas is changed to [N] /
An experiment was conducted in the same manner as the above etching condition c except that [Cl] was changed variously, and the experiment result was
The horizontal axis of the figure shows the ratio [N] / [Cl], and the vertical axis shows the side etching amount [μm]. The values obtained by measurement in the experiment are shown by plotting with white circles. In this experiment, S
TiN upper barrier layer 24 through the SiO ₂ etching mask
The sidewall barrier layer 22 is substantially not formed.

As can be understood from FIG. 14, the ratio [N]
/ [Cl] increases, the side etching amount of the Cu wiring main material layer 14 decreases, and when [N] / [Cl] exceeds about 2, the side etching amount is almost zero, that is, the side of the Cu wiring main material layer 14 It can be seen that the etching is gone.

Therefore, in order to prevent side etching of the Cu wiring main material layer 14, it is preferable that [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> 0. Recognize.

Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
Side etching can be prevented, and the side wall barrier layer 2
Since the etching of the side wall barrier layer 22 is stopped at the deposition position of 2, the overetching of the Cu wiring main material layer 14 can be prevented or the amount of the overetching can be reduced, so that the Cu wiring main material layer 14 can be wired without trouble. Can be processed into a shape.

FIG. 15 is a diagram showing the relationship between the ratio [Si] / [Cl] and the thickness of the sidewall barrier layer. In the figure,
Similar to the above-described embodiment, the TiN lower barrier layer 12, the Cu wiring main material layer 14 and the TiN upper barrier layer 24 are laminated on the underlayer 10, and then the SiO ₂ etching mask 20 is formed. Then, the upper barrier layer 2 is formed through the TiN etching mask 20 by the reactive ion etching method.
4. The thickness of the SiON side wall barrier layer 22 when the wiring main material layer 14 and the lower barrier layer 12 are etched is experimentally examined. The experimental results when the experiment is performed in the same manner as the etching condition c described above except that [Si] / [Cl] is variously changed are shown by plotting with a black square. The ratio [Si] / [Cl] is plotted on the horizontal axis and the thickness of the sidewall barrier layer 22 is plotted on the vertical axis (thickness in the direction along the underlying surface).
[Nm] is shown.

As can be understood from FIG. 15, [Si]
By setting / [Cl] to about 0.2, the thickness of the sidewall barrier layer 22 can be set to about 70 nm. This thickness is Cu
The thickness is sufficient to prevent oxidation of the wiring main material layer 14 and diffusion of Cu.

Further, in order to prevent the main wiring material layer 14 from being oxidized, it is preferable that [O] / [N] <0.1.
When [O] / [N] ≧ 0.1, the resistance of the wiring main material layer 14 increases due to the oxidation of the wiring main material layer 14. However, by setting [O] / [N] <0.1, the oxidation of the wiring main material layer 14 can be suppressed to such an extent that a wiring resistance practically desired can be obtained.

According to this embodiment, the following advantages can be obtained.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, the upper barrier layer 24, the wiring material layer 1
4 and the lower barrier layer 12 are etched into a wiring shape, the sidewall barrier layer 22 is sequentially deposited on the etched sidewall surface generated in the etching process. Therefore, even if thermal stress acts between the wiring gathering layer 14 and the upper barrier layer 24 and the lower barrier layer 12, these barrier layers 24,
It can prevent that 12 peels from the wiring gathering layer 14 by thermal stress.

Thirdly, the etching gas is an oxygen-based gas O ₂
Therefore, the oxygen content of the SiON sidewall barrier layer 22 can be controlled by adjusting the flow rate of the oxygen-based gas O ₂ in the etching process during the deposition of the SiON sidewall barrier layer 22. By controlling the oxygen content of the SiON sidewall barrier layer 22, the Cu diffusion suppressing effect can be enhanced.

The twenty-first aspect of the invention is not limited to the above-mentioned embodiment, and various modifications can be made.

For example, (4-A) SiC as the main source gas
When l ₄ is used, SiO is used as an etching mask.
₂ , a single layer film composed of one kind of film selected from SiN and SiON or a multilayer film composed of plural kinds of films may be used.

As (4-B) main raw material gas, one or both of Ti chloride and Zr chloride can be used. It is preferable to use TiCl ₄ as the Ti chloride and ZrCl ₄ as the Zr chloride. in this case,
As an etching mask, Ti film, Zr film, Ti and Z
A single-layer film made of one kind of film selected from a compound film containing one of r and a compound film containing both Ti and Zr, or a multilayer film made of a plurality of kinds of films can be used. As the compound film containing one of Ti and Zr, T
It is preferable to use TiZr, TiZrN or TiZrON as the compound film containing both iN, TiON, ZrN or ZrON, Ti and Zr.

Further, (4-C) Ti, Zr, TiN, Ti
ON, ZrN, ZrON, TiZr, TiZrN and T
iZrON has advantages of having conductivity, having a coefficient of thermal expansion close to that of Cu, and having an effect of suppressing diffusion and an effect of preventing oxidation of Cu, W, Ta, Al and other elements constituting the wiring main material layer. Have. Therefore, Ti, Zr, TiN, TiON, ZrN, ZrO is used as the lower barrier layer.
Forming N, TiZr, TiZrN or TiZrON,
Ti, Zr, TiN, TiON, Z as the upper barrier layer
rN, ZrON, TiZr, TiZrN or TiZrO
N is formed and TiON, ZrON, and
Alternatively, it is preferable to form TiZrON. Further, Cu, W, Ta, Al, or others can be used as the wiring main material layer.

One or both of O ₂ and O ₃ can be used as the (4-D) oxygen-based gas.

As the (4-E) nitrogen-based gas, one or both of N ₂ and N ₂ O can be used. Alternatively, NH ₃ may be included as the nitrogen-based gas. When NH ₃ is contained, the chlorine content of the sidewall barrier layer can be reduced by the action of NH ₃ , so that corrosion of the wiring main material layer due to chlorine can be made less likely to occur.

[Embodiment of the Invention of Claim 10] In this embodiment, TiCl ₄ as a main raw material gas, Cl ₂ as a chlorine-based gas, N ₂ as a nitrogen-based gas and O as an oxygen-based gas.
₂ using a reactive etching gas of TiC
It is a mixed gas of l ₄ , Cl ₂ , N ₂ and O ₂ . Therefore, the main source gas is a chloride containing Ti which is a constituent element of the sidewall barrier. A single layer film made of TiN is used as an etching mask. Therefore, the etching mask is a film containing Ti as a sidewall barrier constituent element.

(1: Step of Laminating Lower Barrier Layer and Wiring Main Material Layer Sequentially on Underlayer) In this embodiment, first, a Si substrate on which a semiconductor element is formed and a SiO ₂ film formed on the semiconductor element are formed. Prepare a base 10 consisting of and
The TiN lower barrier layer 12 having a thickness of about 0.1 μm and Cu having a thickness of about 0.6 μm are sequentially deposited on the upper side by a sputtering method.
The wiring main material layer 14 is laminated (FIG. 1 (A) to FIG. 1).
(B)).

For example, a mixed gas of Ar and N ₂ is used as an atmospheric gas (sputtering gas) and the atmospheric gas pressure is 5 mTorr.
By the DC sputtering method with r, the TiN lower barrier layer 1
Stack two. Further, the Cu wiring main material layer 14 is laminated by a sputtering method using Ar as an atmospheric gas.

(2: Step of forming an etching mask which also functions as an upper barrier layer on the wiring main material layer) Next, in this embodiment, a thickness of about 1.0 μm is formed on the Cu wiring main material layer 14 by the sputtering method. The TiN mask material 16 is laminated (FIG. 1C).

A semiconductor element such as MOSFET is formed on the base 10.
Even when the TiN lower barrier layer 12 is formed, according to a conventionally known thin film forming technique such as a sputtering method, the TiN lower barrier layer 12 is formed at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element.
The Cu wiring main material layer 14 and the TiN mask material 16 can be laminated.

The TiN lower barrier layer 12 and the TiN mask material 16 may be made of Ti _X N _1-X (0.5 ≦ X ≦ 1, for example X = 0.5).

Next, a resist is applied to the TiN mask material 16 to a thickness of 1 μm, and then the resist is exposed and developed to form a resist pattern 18 (FIG. 2).
(A)). The planar shape of the resist pattern 18 is a wiring shape.

Next, a conventionally known dry etching technique, reactive ion etching (RIE: Reacti) is used here.
The TiN mask material 16 is etched into a wiring shape through the resist pattern 18 by a ve Ion Etching) method to form a TiN etching mask 20 made of this material 16 (FIG. 2B). The TiN etching mask 20 also serves as the upper barrier layer, and the portion remaining on the Cu wiring main material layer 14 after the deposition of the sidewall barrier layer described later functions as the upper barrier layer.

When forming the TiN etching mask 20, it is preferable to select etching conditions so that the TiN mask material 16 is etched but the Cu wiring main material layer 14 is not etched. For example, in the case of reactive ion etching, the etching is performed with Cl ₂ as the reactive etching gas and room temperature as the base temperature,
The TiN mask material 16 can be etched so as not to etch the Cu wiring main material layer 14.

Even when the semiconductor element is formed on the underlayer 10, the etching mask 20 is formed by a well-known etching technique such as a reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. it can.

Next, the resist pattern 18 is removed by ashing treatment using O ₂ plasma (FIG. 3).
(A)).

(3: By the reactive ion etching method,
While etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of an etching mask and a reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. In the example,
The Cu wiring main material layer 14 and the TiN lower barrier layer 12 are formed through the TiN etching mask 20 by a reactive ion etching method using a mixed gas of TiCl ₄ , Cl ₂ , N ₂ and O ₂ as a reactive etching gas. By sequentially etching, the main material layer 14 and the barrier layer 12 are processed into a wiring shape. During this etching process, TiCl ₄ , C
The reaction product T of the reactive etching gas, which is a mixed gas of l ₂ , N ₂ and O ₂ , and the TiN etching mask 20.
iON is the side wall surface 20a of the TiN etching mask 20.
And the side wall surface 14a of the Cu wiring main material layer 14 which is etched
And the TiON side wall barrier layer 22 formed on the etching-processed side wall surface 12a of the lower barrier layer 12 and formed of this reaction product.
It can be deposited in a in a self-aligned manner. Further, after the etching process of the TiN lower barrier layer 12 is completed, the TiN etching mask 20 remaining on the Cu wiring main material layer 14 functions as the TiN upper barrier layer 24. Therefore, it is processed into a wiring shape,
TiN lower barrier layer 12, TiN barrier layer 24 and Ti
The Cu wiring main material layer 14 covered with the ON sidewall barrier layer 22 can be obtained (FIG. 3B).

Even when the semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 and the TiN lower barrier layer are formed by the reactive ion etching method at a temperature low enough not to deteriorate the electrical characteristics of the semiconductor element. 12 can be etched and a TiN sidewall barrier layer 22 can be deposited.

[0299] The etching mechanism of this embodiment is claimed in claim 21.
The etching conditions may be set as follows, for example, since they can be considered in the same manner as the embodiment. A magnetron reactive ion etching device is used as an etching device, and TiCl ₄ , Cl ₂ , and
The gas flow rates of N ₂ and O ₂ were 20 SCCM and 10 respectively.
SCCM, 120SCCM and 5SCCM, etching gas pressure is 35 mTorr, and RF power is 500W.
The base temperature at the time of etching is 250 to 400 ° C. which is suitable for etching the Cu wiring main material layer 14 and is 300 ° C. here.

Further, Ti element and Cl contained in the etching gas
The total number of Ti elements, the total number of Cl elements, the total number of Cl elements, the total number of N elements, and the total number of O elements, which are elements and N elements, are supplied per unit time into the etching chamber of the etching apparatus at 0 ° C. and 1 atm. [Ti], [Cl],
When expressed as [N] and [O], the TiON side wall barrier layer 22
The side etching amount of the Cu wiring main material layer 14 at the time of depositing can be controlled according to the size of the ratio [N] / [Cl], and the thickness of the sidewall barrier layer 22 can be controlled by the ratio [Ti] / [Cl].
Of the wiring main material layer 14 and the oxidation of the wiring main material layer 14 can be controlled according to the size of the ratio [O] / [N].

The etching gas is TiCl ₄ , Cl ₂ , N
₂ and O _{2 as} a mixed gas, TiCl ₄ , Cl ₂ , and TiCl ₄ at the time of etching for depositing the sidewall barrier layer 22
The gas flow rates of N ₂ and O ₂ are 20 SCCM and 1 respectively.
With 0 SCCM, 120 SCCM and 5 SCCM, [Ti], [Cl], [N] and [O] are as follows.

The number of Ti elements and the number of Cl elements contained in TiCl ₄ per unit volume (here, per 1000 cc) at 0 ° C. and 1 atmospheric pressure are Avogadro's number 6.02.
Using x10 ²³ (mol ⁻¹ ), 6.02 × 10 ²³ for Ti element and 6.02 × 1 for Cl element
It becomes 0 ²³ × 4 = 2.408 × 10 ²⁴ pieces. Similarly,
C contained in Cl ₂ per unit volume at 0 ° C. and 1 atm
The number of 1 elements is 6.02 × 10 ²³ × 2 = 1.204 ×
10 ²⁴ , N per unit volume at 0 ° C and 1 atm
The number of N elements contained in ₂ is 6.02 × 10 ²³ × 2 = 1.
204 × 10 ²⁴ , and the number of O elements contained in O ₂ per unit volume at 0 ° C. and 1 atmosphere is 6.02 × 10.
²³ × 2 = 1.204 × 10 ²⁴ pieces.

Therefore, TiCl ₄ gas flow rate: 20 SCC
M, Cl ₂ gas flow rate; 10 SCCM, N ₂ gas flow rate; 120 SCCM, O ₂ gas flow rate; 5 SCCM at 0 ° C., 1 atmosphere per unit volume and per unit time (here, per minute) etching chamber The number of each element flowing into is [Ti] = 6.02 × 10 ²³ ×
(20/1000) = 1.2 × 10 ²² pieces, [Cl] =
2.408 × 10 ²⁴ × (20/1000) +1.20
4 × 10 ²⁴ × (10/1000) = 6.02 × 10
²² pieces, [N] = 1.204 × 10 ²⁴ × (120/1
000) = 1.44 × 10 ²³ pieces, and further [O] = 1.
204 x 10 ²⁴ x (5/1000) = 6.02 x 10
²³ . The etching gas is TiCl ₄ , Cl ₂ ,
Since a mixed gas of N ₂ and O ₂ is used, these TiC
The ratio [N] / [Cl] and the ratio [Ti] / [Cl] and the ratio [O] / [N] can be adjusted by appropriately adjusting the gas flow rates of l ₄ , Cl ₂ , N ₂ and O ₂ , respectively. And can be controlled independently.

Therefore, in order to prevent side etching of the Cu wiring main material layer 14, it is preferable that [N] / [Cl]> 2, that is, 0.5> [Cl] / [N]> O.
[N] / [Cl] ≦ 2, that is, 0.5 ≦ [Cl] /
This is because when it becomes [N], side etching of the Cu wiring main material layer 14 occurs.

Thus, the ratio [N] / [Cl] or [C]
Cu wiring main material layer 14 by controlling 1] / [N]
Side etching can be prevented, and the side wall barrier layer 2
Since the etching of the side wall barrier layer 22 is stopped at the deposition position of 2, the overetching of the Cu wiring main material layer 14 can be prevented or the amount of the overetching can be reduced, so that the Cu wiring main material layer 14 can be wired without trouble. Can be processed into a shape.

By setting [Ti] / [Cl] = 0.2, the side wall barrier layer 22 having a thickness of 70 nm can be formed, and this thickness prevents oxidation of the Cu wiring main material layer 14 and diffusion of Cu. Thick enough to do so.

Further, in order to prevent the main wiring material layer 14 from being oxidized, it is preferable that [O] / [N] <0.1.
If [O] / [N] ≧ 0.1, the wiring resistance of the wiring main material layer 14 increases due to the oxidation of the wiring main material layer 14, but [O] /
By setting [N] <0.1, the oxidation of the wiring main material layer 14 can be suppressed to such an extent that a wiring resistance practically desired can be obtained.

At the time when the etching of the TiN lower barrier layer 12 into the wiring shape is completed, in order to generate the remaining portion of the TiN etching mask 20 functioning as the TiN upper barrier layer 24, T before the etching is started.
The thickness T _E of the iN etching mask 20 may be set so as to satisfy the following equation.

T _E > [etching rate of etching mask 20] × {[thickness of wiring main material layer 14] / [etching rate of wiring main material layer 14] + [thickness of lower barrier layer 12] / [ Etching Rate of Lower Barrier Layer 12]} According to this example, the following advantages can be obtained.

First, even when a semiconductor element is formed on the underlayer 10, the Cu wiring main material layer 14 is processed into a wiring shape and the Cu wiring main material layer 14 is processed into a wiring shape at a temperature low enough not to deteriorate the characteristics of the semiconductor element. The material layer 14 can be covered with the lower barrier layer 12, the upper barrier layer 24 and the sidewall barrier layer 22.

Second, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, the thermal expansion coefficients of these barrier layers 12, 24 and 22 and the Cu wiring main material layer 14 are made. The difference from the coefficient of thermal expansion can be reduced. Therefore, these barrier layers 12, 24 and 22 can improve the SM resistance of the wiring main material layer 14.

Thirdly, since the lower barrier layer 12 and the upper barrier layer 24 are made of TiN and the side wall barrier layer 22 is made of TiON, these barrier layers 12, 24 and 22 are conductive. Therefore, the barrier layers 12, 24, and 22 can improve the EM resistance of the wiring main material layer 14.

Fourth, the etching gas is an oxygen-based gas O ₂
Therefore, the oxygen content rate of the TiON sidewall barrier layer 22 can be controlled by adjusting the flow rate of the oxygen-based gas O ₂ in the etching process during the deposition of the TiON sidewall barrier layer 22. By controlling the oxygen content of the TiON sidewall barrier layer 22, the Cu diffusion suppression effect can be enhanced.

The invention of claim 10 is not limited to the above-mentioned embodiment, and therefore various modifications can be made.

For example, as (5-A) main source gas, T
One or both of i chloride and Zr chloride can be used. It is preferable to use TiCl ₄ as the Ti chloride and ZrCl ₄ as the Zr chloride.

As a (5-B) etching mask,
Ti film, Zr film, compound film containing one of Ti and Zr,
Also, a single-layer film made of a kind of film selected from compound films containing both Ti and Zr can be used.
As the compound film containing one of Ti and Zr, TiN,
The compound film containing both TiON, ZrN or ZrON, Ti and Zr may be TiZr, TiZrN or Ti.
It is preferable to use ZrON.

For example, in the above-mentioned embodiment of the invention of claim 5, the etching mask 20 is a TiN single layer film, but instead of the TiN single layer film, a TiON single layer film, a ZrN single layer film or a ZrON single layer film. The film may be formed as the etching mask 20. Etching mask 20 for TiON single layer film
In that case, the TiON sidewall barrier layer 22 can be formed, and T
iON can be expected to have a Cu diffusion suppression effect equal to or higher than that of TiN. ZrN single layer film or ZrON etching mask 2
When it is set to 0, the TiZrON side wall barrier layer 22 can be formed, and the Cu diffusion suppression effect of TiZrON is TiN or T.
It is considered to be equivalent to iON.

(5-C) Ti, Zr, TiN, Ti
ON, ZrN, ZrON, TiZr, TiZrN and T
iZrON has conductivity and has a thermal expansion coefficient close to that of Cu, and has a diffusion inhibiting effect and an antioxidant effect on Cu, W, Ta, Al and other wiring main material layer constituent elements. Have advantages. Therefore, Ti, Zr, TiN, TiON, ZrN, ZrO is used as the lower barrier layer.
Forming N, TiZr, TiZrN or TiZrON,
Ti, Zr, TiN, TiON, Z as the upper barrier layer
rN, ZrON, TiZr, TiZrN or TiZrO
N is formed and TiON and ZrO are used as the sidewall barrier layer.
It is preferred to form N, or TiZrON. Further, Cu, W, Ta, Al, or others can be used as the wiring main material layer.

(5-D) SiCl as the main source gas
No. ₄ , using a SiN single layer film or S as an etching mask
An iON single layer film may be used.

Further, one or both of O ₂ and O ₃ may be included in the etching gas as the (5-E) oxygen-based gas.

One or both of N ₂ and N ₂ O may be included in the etching gas as the (5-F) nitrogen-based gas.

Also, NH _{3 is used as the} etching gas (5-G).
May be included. By including NH ₃ , the chlorine content of the sidewall barrier layer 22 can be reduced, and thus corrosion of the wiring main material layer 14 due to Cl can be made less likely to occur.

Furthermore, claim 1, claim 5, and claim 10
In carrying out the invention of (1), the etching mask may be a single layer film or a multilayer film. Ti, Zr, T
iN, TiON, ZrN, ZrON, TiZr, TiZ
It is preferable to use a multilayer film composed of a plurality of types of films selected from rN and TiZrON.

When an etching mask composed of a first layer and a second layer sequentially laminated on the wiring main material layer is formed,
The sidewall barrier layer is formed by the reaction of the second layer with the reactive etching gas, leaving the first layer as the upper barrier layer. In this case, the first layer can function as an etching stop layer made of a material having an etching rate lower than the etch rate of the second layer, and thus overetching of the second layer that remains as the upper barrier layer can be prevented. . Alternatively, the first layer can function as an adhesion layer made of a material having good adhesion to the wiring main material layer.
When the combination of the second layer and the first layer in this case is represented by (second layer / first layer), when the first layer is used as an etching stop layer (Ti / TiON), (TiN
/ TiON), (Zr / ZrON) or (ZrN / Zr
ON), or (TiON / TiN), (Zr / ZrN), (ZrO) when the first layer is an adhesion layer.
N / ZrN), (TiON / ZrN), (ZrON / T
iN), (Zr / TiN), or a combination of (Ti / ZrN).

When an etching mask composed of a first layer, a second layer and a third layer which are sequentially stacked on the wiring main material layer is formed, the sidewall barrier is formed by the reaction of the third layer and the reactive etching gas. Layers may be formed and the first and second layers may remain as upper barrier layers. In this case, the first layer is made to function as an adhesion layer made of a material having good adhesion to the wiring main material layer, and the second layer is made of an etching stopper made of a material having an etching rate lower than that of the third layer. It has the advantage that it can function as a layer. If the combination of the third layer, the second layer and the first layer in this case is represented by (third layer / second layer / first layer), (Ti / TiON / TiN), (Ti / TiN) /
Ti), (Zr / ZrON / ZrN) or (Zr / Zr
N / Zr) can be mentioned.

[0326]

As is apparent from the above description, according to the wiring forming method of the inventions of claims 1, 5 and 10, an etching mask is used when the wiring main material layer is etched. A reaction product is generated with the reactive etching gas. And mainly this reaction product,
A sidewall barrier layer is formed by depositing on the sidewall surface of the wiring main material layer that has been etched. Therefore, since the side wall barrier layer can be formed in parallel with the etching, the heat treatment for forming the side wall barrier layer can be omitted, and as a result, the side wall barrier layer can be formed at a lower temperature than in the conventional case. Forming the lower barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique, and forming the etching mask that also serves as the upper barrier layer at a low temperature is easily performed by, for example, a conventionally known thin film forming technique and etching technique. Can be achieved.

According to the first, fifth and tenth aspects of the present invention, the laminated thickness of the sidewall barrier layer is set to 0 ° C. and 1 atm for the sidewall barrier constituent element and the chlorine element contained in the reactive etching gas. In (1), it can be changed according to the ratio (1) of the number of side wall barrier constituent elements and chlorine elements supplied per unit time into the etching chamber. Further, side etching may occur in the wiring main material layer in the process of depositing the side wall barrier layer. However, the side etching amount is 0 ° C. when the nitrogen element and the chlorine element contained in the reactive etching gas are 1 ° C. It can be changed according to the ratio (2) of the numbers of nitrogen element and chlorine element supplied per unit time into the etching chamber at atmospheric pressure. These ratios (1) and (2) can be independently controlled by individually adjusting the flow rates of the main raw material gas, the chlorine-based gas, and the nitrogen-based gas contained in the reactive etching gas, so that the sidewall barrier layer stacking is performed. The thickness and the amount of side etching can be controlled independently.

According to the wiring forming method of the first aspect of the present invention, a compound containing one or both of Ti and Zr can be formed as the sidewall barrier layer. The coefficient of thermal expansion of the compound containing one or both of Ti and Zr has a small difference from the coefficient of thermal expansion of Cu. Therefore, the side wall barrier layer made of such a compound is SM of the wiring main material layer made of Cu. It is useful for improving the resistance or for improving the SM resistance of the wiring main material layer made of a material having a thermal expansion coefficient similar to that of Cu.

Further, since the compound containing one or both of Ti and Zr has conductivity, the sidewall barrier layer made of such a compound is useful for improving the EM resistance of the wiring main material layer.

According to the wiring forming method of the fifth aspect, at least NH ₃ is used as the nitrogen-based gas contained in the reactive etching gas. In the process of depositing the side wall barrier layer, NH ₃ promotes the dissociation of the side wall barrier constituent element and Cl in the main source gas, so that Cl taken into the side wall barrier layer in the deposition process can be reduced. As a result, according to the invention of claim 5, corrosion of the wiring main material layer due to Cl can be made difficult to occur.

According to the wiring forming method of the tenth aspect of the present invention, the sidewall barrier layer is a barrier layer containing oxygen, and the reactive etching gas contains oxygen containing O for controlling the oxygen content of the sidewall barrier layer. Mix the system gases. Therefore, if the reactive etching gas contains oxygen and nitrogen elements,
Depending on the ratio of the numbers of oxygen elements and nitrogen elements supplied per unit time into the etching chamber at 1 ° C and 1 ° C,
The oxygen content of the sidewall barrier layer can be controlled. Since the barrier property of the side wall barrier layer containing oxygen changes depending on the oxygen content, the side wall barrier layer having excellent barrier property can be formed by controlling the oxygen-based gas flow rate.

Further, according to the wiring formation method of the sixteenth and twenty-first aspects, when etching the wiring main material layer, a reaction product is generated between the etching mask and the reactive etching gas. Then, the side wall barrier layer is formed mainly by depositing this reaction product on the side wall surface of the wiring main material layer that has been etched. Therefore, since the sidewall barrier layer can be formed in parallel with the etching, the heat treatment for forming the sidewall barrier layer can be omitted,
As a result, the sidewall barrier layer can be formed at a lower temperature than in the conventional case. Forming the lower barrier layer and the upper barrier layer at low temperature is easily achieved by, for example, a conventionally known thin film forming technique, and forming the etching mask at a low temperature is easily achieved by, for example, a conventionally well known thin film forming technique and etching technique. it can.

According to the sixteenth and twenty-first aspects of the invention, the laminated thickness of the side wall barrier layer is set to 0 ° C. for the side wall barrier constituent element and chlorine element contained in the reactive etching gas,
It can be changed in accordance with the ratio (1) of the numbers of the sidewall barrier constituent element and the chlorine element supplied per unit time into the etching chamber at 1 atm. Further, side etching may occur in the wiring main material layer in the process of depositing the side wall barrier layer. However, the side etching amount is 0 ° C. when the nitrogen element and the chlorine element contained in the reactive etching gas are 1 ° C. It can be changed according to the ratio (2) of the numbers of nitrogen element and chlorine element supplied per unit time into the etching chamber at atmospheric pressure. These ratios (1) and (2) can be independently controlled by individually adjusting the flow rates of the main raw material gas, the chlorine-based gas, and the nitrogen-based gas contained in the reactive etching gas, so that the sidewall barrier layer stacking is performed. The thickness and the amount of side etching can be controlled independently.

According to the sixteenth aspect of the present invention, the nitrogen-based gas contained in the reactive etching gas is at least N 2.
H ₃ is used. In the process of depositing the sidewall barrier layer,
Since NH ₃ promotes the dissociation of the side wall barrier constituent element and Cl in the main source gas, Cl taken into the side wall barrier layer during the deposition process can be reduced. As a result, corrosion of the sidewall barrier layer due to Cl can be suppressed.

According to the twenty-first aspect of the invention, the side wall barrier layer is a barrier layer containing oxygen, and the reactive etching gas is mixed with an oxygen-based gas containing O for controlling the oxygen content of the side wall barrier layer. To do. The oxygen content of the sidewall barrier layer is determined by the ratio (3) of the oxygen element and the nitrogen element contained in the reactive etching gas, which are supplied to the etching chamber at 0 ° C. and 1 atmosphere per unit time. You can control. Since the barrier property of the side wall barrier layer containing oxygen changes according to the oxygen content, the side wall barrier layer having excellent barrier property can be formed by the ratio (3).

[Brief description of drawings]

FIG. 1A to FIG. 1C are process drawings provided for explaining an example.

FIG. 2A to FIG. 2B are process drawings used to explain an example.

FIG. 3A to FIG. 3B are process drawings for explaining an embodiment of the invention.

FIG. 4 is a diagram showing a relationship between a base temperature and a Cu etching rate.

FIG. 5 is a diagram showing a relationship between [N] / [Cl] and a side etching amount of a wiring main material layer.

FIG. 6 is a diagram showing the relationship between [Ti] / [Cl] and the thickness of the sidewall barrier layer.

FIG. 7 is a diagram showing a relationship between a base temperature and a Cu etching rate.

FIG. 8 is a diagram showing a relationship between [N] / [Cl] and a side etching amount of a wiring main material layer.

FIG. 9 is a diagram showing the relationship between [Ti] / [Cl] and the thickness of the sidewall barrier layer.

10 (A) to (C) are process drawings provided for explaining an example.

11 (A) to (C) are process charts provided for explaining an example.

12 (A) to (B) are process drawings for explaining an embodiment of the invention.

FIG. 13 is a diagram showing a relationship between a base temperature and a Cu etching rate.

FIG. 14 is a diagram showing a relationship between [N] / [Cl] and a side etching amount of a wiring main material layer.

FIG. 15 is a diagram showing the relationship between [Si] / [Cl] and the thickness of the sidewall barrier layer.

[Explanation of symbols]

 10: Base 12: Lower barrier layer 14: Wiring main material layer 20: Etching mask 22: Side wall barrier layer 24: Upper barrier layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/88 M

Claims (26)

[Claims] 1. A step of sequentially laminating a lower barrier layer and a wiring main material layer on a lower surface, a step of forming an etching mask also serving as an upper barrier layer on the wiring main material layer, and a reactive ion etching method. By etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of the etching mask and the reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. The reactive etching gas is a main source gas composed of chloride containing a sidewall barrier constituent element, a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer, and a wiring main material layer. Is mixed with a nitrogen-based gas containing N for preventing side etching, and the etching mask is made of a film containing a sidewall barrier constituent element. One or both of Ti chloride and Zr chloride is used as the etching mask, and the etching mask includes a Ti film, a Zr film, a compound film containing one of Ti and Zr, and a compound film containing both Ti and Zr. A method of forming a wiring, comprising using a single layer film made of one kind of film selected from the above or a multilayer film made of plural kinds of films. 2. The wiring forming method according to claim 1, wherein one or both of TiCl ₄ and ZrCl ₄ is used as a main material gas, and a Ti film, a TiN film, and TiON are used as an etching mask.
Film, Zr film, ZrN film, ZrON film, TiZr film, Ti
A wiring forming method using a single layer film made of one kind of film selected from a ZrN film and a TiZrON film or a multi-layered film made of plural kinds of films. 3. The wiring forming method according to claim 1, wherein Cl ₂ is used as the chlorine-based gas. 4. The wiring forming method according to claim 1, wherein one or both of N ₂ and N ₂ O is used as the nitrogen-based gas. 5. A step of sequentially laminating a lower barrier layer and a wiring main material layer on a lower surface, a step of forming an etching mask also serving as an upper barrier layer on the wiring main material layer, and a reactive ion etching method. By etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of the etching mask and the reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. The reactive etching gas is a main source gas composed of chloride containing a sidewall barrier constituent element, a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer, and a wiring main material layer. Is mixed with a nitrogen-based gas containing N for preventing side etching of the film, and the etching mask is formed of a film containing a sidewall barrier constituent element. As a wiring forming method, which comprises using at least NH _3. 6. The wiring forming method according to claim 5, wherein one or both of TiCl ₄ and ZrCl ₄ is used as a main material gas, and a Ti film, a TiN film, and TiON are used as an etching mask.
Film, Zr film, ZrN film, ZrON film, TiZr film, Ti
A wiring forming method, wherein a single layer film made of one kind of film selected from a ZrN film and a TiZrON film or a multi-layered film made of plural kinds of films is used. 7. The wiring forming method according to claim 5, wherein SiCl ₄ is used as a main source gas, and a single layer film or a plurality of films made of one kind of film selected from a SiN film and a SiON film is used as an etching mask. A method for forming a wiring, comprising using a multilayer film made of a seed film. 8. The wiring forming method according to claim 5, wherein Cl ₂ is used as the chlorine-based gas. 9. The wiring forming method according to claim 5, wherein one or both of N ₂ and N ₂ O is used as the nitrogen-based gas in addition to NH ₃ . 10. A step of sequentially laminating a lower barrier layer and a wiring main material layer on a lower surface, a step of forming an etching mask also serving as an upper barrier layer on the wiring main material layer, and a reactive ion etching method. By etching the wiring main material layer into a wiring shape, a sidewall barrier layer mainly composed of a reaction product of the etching mask and the reactive etching gas is deposited on the etching-processed sidewall surface of the wiring main material layer. The reactive etching gas is a main source gas composed of chloride containing a sidewall barrier constituent element, a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer, and a wiring main material layer. Is mixed with a nitrogen-based gas containing N for preventing side etching of the sidewall barrier, and the etching mask is formed of a film containing a sidewall barrier constituent element. The A layer was a barrier layer containing oxygen, the reactive etching gas, wiring forming method characterized by comprising a mixture of oxygen-based gas containing O to control the oxygen content of the side wall barrier layer. 11. The wiring forming method according to claim 10, wherein one or both of TiCl ₄ and ZrCl ₄ is used as a main source gas, and a Ti film, a TiN film, and TiON are used as an etching mask.
Film, Zr film, ZrN film, ZrON film, TiZr film, Ti
A wiring forming method, wherein a single layer film made of one kind of film selected from a ZrN film and a TiZrON film or a multi-layered film made of plural kinds of films is used. 12. The wiring forming method according to claim 10, wherein SiCl ₄ is used as a main source gas, and a single layer film or a plurality of films made of one kind of film selected from a SiN film and a SiON film is used as an etching mask. A method for forming a wiring, comprising using a multilayer film made of a seed film. 13. The wiring forming method according to claim 10, wherein Cl ₂ is used as the chlorine-based gas. 14. The wiring forming method according to claim 10, wherein one or both of N ₂ and N ₂ O is used as the nitrogen-based gas. 15. The wiring forming method according to claim 10, wherein one or both of O ₂ and O ₃ is used as the oxygen-based gas. 16. A step of sequentially laminating a lower barrier layer, a wiring main material layer and an upper barrier layer on a lower surface, a step of forming an etching mask on the upper barrier layer, and a reactive ion etching method. A step of depositing a side wall barrier layer mainly composed of a reaction product of the etching mask and the reactive etching gas on the side wall surface of the wiring main material layer which is etched while etching the main wiring material layer into a wiring shape. The reactive etching gas includes a main source gas composed of chloride containing a sidewall barrier constituent element, a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer, and a wiring main material layer The nitrogen-based gas containing N for preventing side etching is mixed, and the etching mask is a film containing a sidewall barrier constituent element. To the wiring formation method which comprises using at least NH _3. 17. The wiring forming method according to claim 16, wherein one or both of TiCl ₄ and ZrCl ₄ is used as a main source gas, and a Ti film, a TiN film, and TiON are used as an etching mask.
Film, Zr film, ZrN film, ZrON film, TiZr film, Ti
A wiring forming method characterized by using a ZrN film or a TiZrON film. 18. The wiring forming method according to claim 16, wherein SiCl ₄ is used as a main raw material gas, and a SiO ₂ film, a SiN film or S is used as an etching mask.
A wiring forming method characterized by using an iON film. 19. The wiring forming method according to claim 16, wherein Cl ₂ is used as the chlorine-based gas. 20. The wiring forming method according to claim 16, wherein one or both of N ₂ and N ₂ O is used as the nitrogen-based gas in addition to NH ₃ . 21. A step of sequentially laminating a lower barrier layer, a wiring main material layer and an upper barrier layer on a lower surface, a step of forming an etching mask on the upper barrier layer, and a reactive ion etching method. A step of depositing a sidewall barrier layer mainly composed of a reaction product of the etching mask and a reactive etching gas on the etching-processed sidewall surface of the wiring main material layer while etching the wiring main material layer into a wiring shape; The reactive etching gas includes a main source gas composed of chloride containing a sidewall barrier constituent element, a chlorine-based gas containing Cl for controlling the thickness of the sidewall barrier layer, and a side of the wiring main material layer. The etching mask is formed by mixing with a nitrogen-based gas containing N for preventing etching, and the etching mask is formed of a film containing a sidewall barrier constituent element. Was a barrier layer containing oxygen, the reactive etching gas, wiring forming method characterized by comprising a mixture of oxygen-based gas containing O to control the oxygen content of the side wall barrier layer. 22. The wiring forming method according to claim 21, wherein one or both of TiCl ₄ and ZrCl ₄ is used as a main material gas, and a Ti film, a TiN film, and TiON are used as an etching mask.
Film, Zr film, ZrN film, ZrON film, TiZr film, Ti
A wiring forming method characterized by using a ZrN film or a TiZrON film. 23. The wiring forming method according to claim 21, wherein SiCl ₄ is used as a main source gas, and a SiO ₂ film, a SiN film, or an S is used as an etching mask.
A wiring forming method characterized by using an iON film. 24. The wiring forming method according to claim 21, wherein Cl ₂ is used as the chlorine-based gas. 25. The wiring forming method according to claim 21, wherein one or both of N ₂ and N ₂ O is used as the nitrogen-based gas. 26. The wiring forming method according to claim 21, wherein one or both of O ₂ and O ₃ is used as the oxygen-based gas.