JP2004071774A - Plasma processing method using multi-chamber system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of undesired effects imposed on an object of plasma processing by plasma, developed during the ashing process from by-products of etching such as an F-containing by-product deposited on processing chamber inner walls or on parts inside the chamber, in case etching and ashing are implemented in one and the same processing chamber. <P>SOLUTION: The plasma processing method comprises a stage of transporting a wafer W into a plasma processing chamber 11 by using a transporting arm 15A, a stage of introducing an F-containing processing gas into the plasma processing chamber 11, a stage of converting the processing gas into plasma for etching an insulating film layer 23 covering an Si-containing barrier layer 22 in the wafer W via an opening 24A provided in a masking layer 24 covering the insulating film 23, a stage of transporting the wafer W from the plasma processing chamber 11 into another processing chamber 12 by using the transporting arm 15A, and a stage of removing the masking layer 24 from the wafer W in the other processing chamber 12. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a plasma processing method using a multi-chamber system.
[0002]
[Prior art]
Conventionally, plasma processing includes, for example, plasma etching (hereinafter, simply referred to as "etching") and plasma ashing (hereinafter, simply referred to as "ashing"). In the etching step, for example, an interlayer insulating layer (for example, an organic insulating layer) in the object to be processed is etched through the pattern opening of the mask layer, and in the ashing step, the mask layer after the plasma etching is removed by ashing. In the conventional plasma processing method, etching and ashing are performed in the same processing container in order to improve throughput.
[0003]
[Problems to be solved by the invention]
However, when etching and ashing are performed in the same processing vessel, a by-product of the etching, for example, a by-product containing F, adheres to the inner wall and internal components of the processing vessel, and this adhered substance is formed during the next ashing step. Plasma is generated, and this plasma acts on the object to be processed, giving an undesired effect, and may degrade device performance.
[0004]
The present invention has been made in order to solve the above problems, and has as its object to provide a plasma processing method using a multi-chamber system capable of performing ashing without being affected by by-products of etching. .
[0005]
[Means for Solving the Problems]
A plasma processing method using a multi-chamber system according to claim 1 of the present invention is a plasma processing method using a multi-chamber system having a plurality of processing containers and a transfer unit, wherein one processing container is provided via the transfer unit. Loading the object to be processed into the processing container, introducing a processing gas containing F into the one processing container, converting the gas into plasma, and covering the first layer containing Si in the object to be processed. Etching the second layer through a pattern opening of the mask layer covering the second layer to expose the first layer, and removing the object from the one processing container via the transport means. And a step of removing the mask layer of the object to be processed in the another processing container.
[0006]
According to a second aspect of the present invention, there is provided a plasma processing method using the multi-chamber system according to the first aspect, wherein the second layer is formed of an organic siloxane. It is.
[0007]
A plasma processing method using a multi-chamber system according to a third aspect of the present invention is a plasma processing method using a multi-chamber system having a plurality of processing vessels and a transfer unit. A step of loading the object to be processed into the processing container; a step of introducing a processing gas containing F into the one processing container; and a step of converting the gas into plasma to form a first layer containing Si in the object to be processed. A step of etching halfway through a pattern opening of the mask layer covering the first layer, and a step of transporting the object to be processed from the one processing vessel into another processing vessel via the transporting means. And removing the mask layer of the object to be processed in the other processing container.
[0008]
Further, in the plasma processing method using the multi-chamber system according to claim 4 of the present invention, in the invention according to any one of claims 1 to 3, the first layer is made of SiN, SiO _2. , And SiC.
[0009]
Further, in the plasma processing method using the multi-chamber system according to claim 5 of the present invention, in the invention according to any one of claims 1 to 3, the first layer is made of polysilicon, It is characterized by being formed of any one selected from crystalline silicon, doped silicon and amorphous silicon.
[0010]
Further, in the plasma processing method using the multi-chamber system according to claim 6 of the present invention, in the invention according to any one of claims 1 to 4, the processing gas is CF ₄ , CHF _3. , CH ₂ F ₂ , CH ₃ F, C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , C ₈ F ₈ The gas is characterized by containing.
[0011]
Further, in the plasma processing method using the multi-chamber system according to claim 7 of the present invention, in the invention according to any one of claims 1 to 6, the mask layer is formed of an organic material. It is characterized by becoming.
[0012]
Also, in the plasma processing method using the multi-chamber system according to claim 8 of the present invention, in the invention according to any one of claims 1 to 7, the mask layer is formed of a photoresist. It is characterized by becoming.
[0013]
In the plasma processing method using the multi-chamber system according to the ninth aspect of the present invention, in the method according to any one of the first to eighth aspects, the step of removing the mask layer may include: It is characterized by using a plasma of a gas containing H ₂ and H ₂ .
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the embodiment shown in FIGS.
First, a multi-chamber system suitably used in the present invention will be described. The multi-chamber system 10 used in the present embodiment includes a plurality (four in the present embodiment) of vacuum processing vessels (hereinafter, referred to as “process chambers”) 11 to 14 as shown in FIG. The first to fourth process chambers 11 to 14 are connected via respective gate valves 11A to 14A, and the pentagonal transfer chamber 15 is connected to the remaining wall surfaces of the transfer chamber 15 via gate valves 16A and 17A. And two cassette chambers 16 and 17. An articulated transfer arm 15A is provided in the transfer chamber 15, and transfers the wafers W one by one from the cassette in the cassette chamber 16 to any of the process chambers 11 to 14 via the transfer arm 15A. The first to fourth process chambers 11 to 14 are configured to generate plasma of a process gas in the process chamber and perform etching or ashing on the wafer W on the susceptors 11B to 14B.
[0015]
Next, an embodiment of a plasma processing method using the multi-chamber system of the present invention will be described with reference to FIG. First, the gate valve 16A of the cassette chamber 16 is opened, the wafer W is loaded into the transfer chamber 15 from the cassette in the cassette chamber 16 via the transfer arm 15A, and then the gate valve 16A is closed. Next, for example, after opening the gate valve 11A of the first process chamber 11, the wafer W is loaded into the first process chamber 11 from the transfer chamber 15 via the transfer arm 15A, and is placed on the susceptor 11B, and the gate valve is opened. Close 11A. Next, a processing gas containing F is introduced as an etching gas while the inside of the first process chamber 11 is evacuated, the etching gas is turned into plasma by a plasma generating means at a predetermined degree of vacuum, and a portion of the wafer W to be subjected to plasma processing is etched. .
[0016]
As shown in, for example, FIG. 2A, the portion of the wafer W to be subjected to the plasma processing includes a metal wiring layer 21, a barrier layer 22 as a first layer containing Si, and a second layer as a second layer. An insulating film layer 23 and a mask layer 24 are formed, and openings 24A are formed in the mask layer 24 in a predetermined pattern. Then, the plasma processing is performed on the target portion of the plasma processing through the opening 24A of the mask layer 24. At the time of the plasma processing, the insulating film layer 23 is etched from the opening 24A of the mask layer 24 using a gas containing fluorocarbon or the like to expose the barrier layer 22 as shown in FIG.
[0017]
Next, the gate valve 11A of the first process chamber 11 is opened, the wafer W after the etching is carried out from the first process chamber 11 to the transfer chamber 15 via the transfer arm 15A, and then the gate valve 11A is closed. Thereafter, for example, the gate valve 12A of the other second process chamber 12 is opened, and the wafer W having the barrier layer 22 after the etching is exposed via the transfer arm 15A from the transfer chamber 15 to the susceptor 12B in the second process chamber 12. And the gate valve 12A is closed. Subsequently, a gas containing N ₂ and H ₂ is introduced into the second process chamber 12 as an ashing gas, the ashing gas is turned into plasma by a plasma generating means, and the mask layer 24 is ashed as shown in FIG. And remove.
[0018]
As described above, the etching of the insulating film layer 23 on the barrier layer 22 and the removal of the mask layer 24 are performed in the first and second process chambers 11 and 12, respectively, so that the etching is performed in the second process chamber 12. Since the mask layer 24 can be removed by ashing in a state where the by-product containing F is not attached, that is, in a state where the fluorine active species acting on the exposed barrier layer 22 is not generated, the barrier layer 22 by the fluorine active species is removed. Shaving can be suppressed, and thus, device degradation can be prevented.
[0019]
Further, while the ashing is performed in the second process chamber 12, the inside of the first process chamber 11 is cleaned as necessary to remove by-products including F by etching to prepare for the next etching. At the time of cleaning, a gas containing O ₂ is introduced into the first process chamber 11, oxygen is converted into plasma through plasma generation means, and this plasma is used.
[0020]
After removing the mask layer 24 of the wafer W in the second process chamber 12, the gate valve 12A is opened, and the wafer W is unloaded from the second process chamber 12 into the transfer chamber 15 via the transfer arm 15A. Then, the gate valve 17A of the cassette chamber 17 is opened. Subsequently, the wafer W after the plasma processing is stored in the cassette in the cassette chamber 17 from the transfer chamber 15 via the transfer arm 15A.
[0021]
Thus, it is preferable that the barrier layer 22 which is the first layer containing silicon is formed of any one of SiN, SiO ₂ , and SiC. Further, the insulating film layer 23 as the second layer covering the barrier layer 22 is preferably an insulating film having a low relative dielectric constant in order to improve device performance. It is preferable that the insulating film layer 23 having a low relative dielectric constant is formed of, for example, organic siloxane. In addition, the insulating film layer 23 as the second layer is formed of, for example, MSQ, porous MSQ (trade name of JSR Corporation: LKD), porous silica, FSG, CVD-SiOC (trade name: CORAL, Black Diamond, etc.). Is preferred. Of course, SiO ₂ can also be used.
[0022]
Examples of the processing gas containing F for etching the insulating film layer 23 as the second layer include CF ₄ , C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₃ F ₈ , and C ₄ F. ₆ , a gas containing at least one of fluorocarbons such as C ₄ F ₈ and C ₈ F ₈ and hydrofluorocarbons such as CHF ₃ , CH ₂ F ₂ and CH ₃ F can be used. In addition, a mixed gas of methane (CH ₄ ), carbon tetrachloride (CCl ₄ ), fluorine (F ₂ ), chlorine trifluoride (ClF ₃ ), or the like can be used. Further, nitrogen (N ₂ ), oxygen (O ₂ ), carbon monoxide (CO), argon (Ar), helium (He), or the like may be added to these. As the mask layer 24, for example, an organic layer is preferable, and as the organic layer, for example, a photoresist is preferable. In order to remove the mask layer 24 by ashing, plasma of a gas containing oxygen (O ₂ ) can be used as an ashing gas in addition to the gas containing N ₂ and H ₂ .
[0023]
As the ashing gas to remove the mask layer 24, a gas containing N _2, or when using a gas comprising N ₂ and H _2, the abrasion of the side surface of the insulating film layer 23 overlying barrier layer 22 containing silicon Can be suppressed.
[0024]
As described above, according to the present embodiment, when performing the etching and ashing plasma processing on the wafer W using the multi-chamber system 10, the transfer arm 15A in the transfer chamber 15 of the multi-chamber 10 is used. Loading the wafer W from the cassette chamber 16 into the first process chamber 11, introducing an etching gas containing F into the first process chamber 11, converting the etching gas into plasma, Etching the insulating film layer 23 covering the barrier layer 22 containing Si through the opening 24A of the mask layer 24 covering the insulating film layer 23 to expose the barrier layer 22; Transfer the wafer W from the first process chamber 11 to another second process chamber 12 via And the step of removing the mask layer 24 of the wafer W in the second process chamber 12, so that the second process chamber is not affected by the by-products including F attached in the first process chamber 11. Ashing is performed on the mask layer 24 in the wafer W in the process chamber 12 to remove the mask layer 24. As a result, it is possible to prevent the barrier layer 22 of the wafer W from being scraped and prevent device performance from deteriorating.
[0025]
In addition, the present invention can be applied to, for example, a case where a groove shown in FIG. 3 is formed. For example, as shown in FIG. 3A, a metal wiring layer 31, a silicon-containing insulating film layer (for example, SiO ₂ film layer) 32 as a first layer, a mask, A layer (photoresist layer) 33 is formed, and openings 33A are formed in the mask layer 33 in a predetermined pattern. In this embodiment, similarly to the above-described embodiment, the wafer W is placed on the susceptor 11A in the first process chamber 11 from the cassette chamber 16 via the transfer arm 15A, and the gate valve 11A is closed. A gas is introduced into the first process chamber 11, the etching gas is turned into plasma through plasma generating means, and the insulating film containing Si is opened from the opening 33A of the mask layer 33 by the plasma as shown in FIG. The layer 32 is partially etched to form a groove 32A (see FIG. 3B). Next, after the transfer from the first process chamber 11 to the second process chamber 12 via the transfer arm 15A, the gate valve 12A is closed, the ashing gas is introduced into the second process chamber 12, and the plasma is supplied through the plasma generating means. The ashing gas is turned into plasma, and the mask layer 33 is ashed and removed by the plasma (see (c) in the figure).
[0026]
Thus, in the above embodiment, as the etching gas in the first process chamber 11, for example, a mixed gas of C ₄ F ₈ (or C ₅ F ₈ , C ₄ F ₆ ), CO, O _2, and Ar is used. Can be used. When the insulating film layer 32 containing silicon is an organic silicon oxide film, N ₂ may be further added. As the ashing gas in the second process chamber 12, for example, it may be used gas, or a gas containing N ₂ and H ₂ containing N _2. In the present embodiment, similarly to the above-described embodiment, while ashing is performed in the second process chamber 12, components in the first process chamber 11 are formed by using, for example, oxygen gas plasma in the first process chamber 11. The by-product containing fluorine adhering to the surface is removed. In this embodiment, the same operation and effect as those of the above embodiment can be expected.
[0027]
【Example】
Hereinafter, examples of the present invention will be specifically described.
Example 1
In the present embodiment, the plasma processing of the wafer W shown in FIG. 2 was performed using the multi-chamber system 10 shown in FIG. In the wafer W used in this example, only the type of the barrier layer 22 was changed to SiN, SiO ₂ , or SiC, the insulating film layer 23 covering the barrier layer 22 was formed of organosiloxane, and the mask layer 24 was formed of photoresist. Have been. After each of these three types of wafers W is loaded into the first process chamber 11, a mixed gas of C ₄ F ₈ , Ar, and N ₂ is supplied into the first process chamber 11 at a predetermined flow rate (C ₄ F ₈ : Ar: N ₂ = 6 sccm: 1000 sccm: 150 sccm) was introduced as an etching gas, and this etching gas was turned into plasma under a pressure of 150 mTorr, for example, and the insulating film layer 23 covering the barrier layer 22 was etched by this plasma. After the etching, each wafer W is transferred from the first process chamber 11 into the second process chamber 12, and then a mixed gas of N ₂ gas and H ₂ gas is introduced into the second process chamber 12 as an ashing gas. The gas was turned into plasma, and the mask layer 24 was ashed by this plasma.
[0028]
Comparative Example 1
In this comparative example, etching and ashing of three types of wafers W were performed in the same first process chamber 11 under the same process conditions as in Example 1.
[0029]
As a result of comparing the etching rate of the barrier layer 22 at the time of ashing of the mask layer 24 of the first embodiment and the comparative example 1, when the barrier layer 22 is silicon nitride, the etching rate of the first embodiment is lower than that of the first comparative example. The ratio was 1/9, that of silicon carbide was 1/17, and that of silicon oxide was 1/66.
[0030]
In the above embodiment, the case where the first layer is formed of SiN, SiO ₂ , or SiC has been described. However, the case where the first layer is formed of polysilicon, single crystal silicon, doped silicon, or amorphous silicon is also described. The present invention can be applied.
[0031]
【The invention's effect】
According to the first to ninth aspects of the present invention, it is possible to provide a plasma processing method using a multi-chamber system capable of performing ashing without being affected by by-products due to etching.
[Brief description of the drawings]
FIG. 1 is a plan view schematically showing an example of a multi-chamber system suitably used in the present invention.
FIG. 2 is a schematic sectional view showing a main part of a wafer used in one embodiment of the present invention.
FIG. 3 is a schematic sectional view showing a main part of a wafer used in another embodiment of the present invention.
[Explanation of symbols]
W Wafer (workpiece)
10 Multi-chamber system 11, 12, 13, 14 Process chamber (processing vessel)
15 Transfer chamber 15A Transfer arm (transport means)
22, 32 barrier layer (first layer)
23, 32 insulating film layer (second layer)
24, 33 mask layer

Claims (9)

In a plasma processing method using a multi-chamber system having a plurality of processing containers and a transfer unit, a step of loading an object to be processed into one processing container via the transfer unit; A step of introducing a processing gas containing the gas, and converting the gas into a plasma to form a second layer covering the first layer containing Si in the object to be processed through a pattern opening of a mask layer covering the second layer. Etching the first layer to expose the first layer; transporting the workpiece from the one processing vessel into another processing vessel via the transporting means; and transporting the workpiece in the other processing vessel. Removing the mask layer of the processing body. A plasma processing method using a multi-chamber system. The plasma processing method according to claim 1, wherein the second layer is formed of an organic siloxane. In a plasma processing method using a multi-chamber system having a plurality of processing containers and a transfer unit, a step of loading an object to be processed into one processing container via the transfer unit; A step of introducing a processing gas containing the gas, a step of converting the gas into a plasma, and etching a part of the first layer containing Si in the object to be processed through a pattern opening of a mask layer covering the first layer. Transporting the object to be processed from the one processing container to another processing container via the transporting means, and removing the mask layer of the object to be processed in the other processing container, A plasma processing method using a multi-chamber system, comprising: 4. The multi-chamber system according to claim 1, wherein the first layer is formed of one selected from SiN, SiO ₂ , and SiC. 5. Plasma processing method using 4. The method according to claim 1, wherein the first layer is formed of any one selected from polysilicon, single crystal silicon, doped silicon, and amorphous silicon. A plasma processing method using the multi-chamber system described in the above section. The processing gas is CF ₄ , CHF ₃ , CH ₂ F ₂ , CH ₃ F, C ₂ F ₄ , C ₂ F ₆ , C ₃ F ₆ , C ₃ F ₈ , C ₄ F ₆ , C ₄ F ₈ , The plasma processing method using the multi-chamber system according to claim 1, wherein the gas is a gas containing at least one of C ₈ F ₈ . 7. The plasma processing method according to claim 1, wherein the mask layer is formed of an organic material. The plasma processing method using a multi-chamber system according to any one of claims 1 to 7, wherein the mask layer is formed of a photoresist. In the step of removing the mask layer, a plasma processing method using a multi-chamber system according to any one of claims 1 to 8 which comprises using a plasma of a gas containing N ₂ and H ₂ .

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