JPH10242122A - Device and method for dry etching - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of a semiconductor wafer by reducing the amount of foreign matters which adhere to the wafer in a dry etching process. SOLUTION: A dry etching device performs etching on a semiconductor wafer W mounted on lower and upper electrodes 20 and 30 counterposed to each other in a treating chamber 10 by generating plasma of a reactive gas 71 by supplying high-frequency power across the electrodes 20 and 30 from a high-frequency power source 40. The peeling of hydrophobic reaction products of etching from the surfaces of susceptors 22 and 32 which are respectively arranged around the electrodes 20 and 30 and composed of quartz is prevented by improving the affinity (adhesion) between the hydrophobic reaction products and the surfaces of the susceptor 22 and 32 by giving a hydrophilic property to the surfaces of the susceptors 22 and 32 by introducing such a material as silicon, carbon, etc. The yield of the semiconductor wafer W can be improved, because the amount of foreign matters which are produced from peeled reaction products of etching and adhere to the surface of the wafer W can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry etching technique, and more particularly to a technique effective when applied to a dry etching step of a semiconductor wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art For example, Industrial Research Institute, Inc., Showa 5
As described in literatures such as “Electronic Materials” issued Nov. 15, 1995, “Electronic Materials” Nov. 1982, P146 to P151, etc., in a dry etching process for an oxide film or the like of a semiconductor wafer, a CF-based material is used. Because an etching gas is used,
As a reaction product, a CF-based polymer is deposited on the inner wall of the reaction chamber.

[0003]

The reaction product deposited and deposited on the inner wall of the reaction chamber during the etching process is peeled off due to a change in temperature, a transfer operation of the semiconductor wafer, and the like, and adheres as a foreign substance to the surface of the semiconductor wafer. . If this foreign matter adheres to the semiconductor wafer at the timing before the start of etching, during the etching, or the like, there is a technical problem that the foreign matter is transferred to the base and causes a pattern defect to lower the yield.

As a countermeasure, for example, it is conceivable to frequently perform cleaning of the inner wall of the reaction chamber of the etching apparatus to suppress the generation of foreign matter. However, the operating rate of the etching apparatus decreases, and the throughput of the entire process decreases. Do
Another technical problem arises.

An object of the present invention is to provide a dry etching technique capable of reducing foreign substances adhering to a semiconductor wafer.

Another object of the present invention is to provide a dry etching technique capable of reducing the occurrence of defects due to the attachment of foreign matter to a semiconductor wafer and improving the yield of semiconductor devices formed on the semiconductor wafer. It is in.

Another object of the present invention is to provide a dry etching technique capable of reducing foreign substances adhering to a semiconductor wafer without lowering the throughput.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0009]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

In other words, the present invention provides a dry etching apparatus for performing dry etching on a semiconductor wafer by supplying a reactive gas into a processing chamber in which a semiconductor wafer is accommodated, thereby exposing the component to the reactive gas. Is made hydrophobic.

[0011] As a constituent member, for example, at least one of the first electrode on which the semiconductor wafer is mounted and the second electrode arranged opposite to the first electrode is provided near the semiconductor wafer. A susceptor made of quartz or the like is conceivable, and the surface of the susceptor is selectively made hydrophobic.

As a method of hydrophobization, a hydrophobic substance such as silicon or carbon is present at a desired concentration on the susceptor surface, or a bipolar molecule having a hydrophilic group and a hydrophobic group is vacuum-deposited or coated or coated. Using the LB method, the hydrophilic group side is attached to the surface of a susceptor made of hydrophilic quartz or the like, and the hydrophobic group side covers the susceptor surface.
It is conceivable to make the surface of the susceptor hydrophobic.

[0013]

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

(Embodiment 1) FIG. 1 is a cross-sectional view showing an example of the structure of a dry etching apparatus according to an embodiment of the present invention, and FIGS. It is sectional drawing which illustrated typically.

Inside the processing chamber 10, a lower electrode 20 on which a semiconductor wafer W is mounted and an upper electrode 30 are vertically opposed to each other and connected to a high frequency power supply 40, respectively.

On the side wall of the processing chamber 10, a semiconductor wafer W
Is provided with a gate valve 50 for carrying in and carrying out the wafer. An exhaust port 60 to which a vacuum pump (not shown) for exhausting the inside of the processing chamber 10 is connected is provided at the bottom of the processing chamber 10.

Further, a part of the processing chamber 10 is
A gas supply mechanism 70 for supplying a reaction gas 71 is connected to the inside.

An electrostatic chuck 21 made of, for example, ceramics such as alumina is provided on the upper surface of the lower electrode 20, and the mounted semiconductor wafer W is fixed by being attracted by static electricity. A susceptor 22 made of, for example, quartz is arranged around the lower electrode 20 so as to surround the semiconductor wafer W.

The lower electrode 20 is provided with wafer push-up pins 23 which penetrate in the thickness direction and move up and down. When loading and unloading the semiconductor wafer W, the electrostatic chuck 21 is used.
To lift the semiconductor wafer W to a predetermined height.

The upper electrode 30 is made of, for example, single crystal silicon or the like, and the back surface thereof is an electrode substrate 31 made of a conductor.
It is supported by. A susceptor 32 made of, for example, quartz is arranged around the upper electrode 30.

Here, the susceptor 22 and the susceptor 32
Is composed of quartz, the quartz is hydrophilic as it is, while the etching reaction product 72 generated in the process of dry etching in the processing chamber 10 as described later is a CF-based reaction gas 71. When the etching gas is used, the composition becomes CxFy (x and y are arbitrary natural numbers) and exhibits hydrophobicity, and therefore, the affinity (bonding strength) between the surface of the susceptor 22 and the susceptor 32 and the etching reaction product 72 is obtained. Is low, as illustrated in FIG.
The etching reaction product 72 is easily separated from the surfaces of the susceptor 22 and the susceptor 32.

Therefore, in the case of the present embodiment, as illustrated in FIG. 2, the surfaces of the susceptor 22 and the susceptor 32 made of quartz are made of hydrophobic silicon to a desired concentration by ion implantation or diffusion. A hydrophobizing substance 80 made of (Si) or carbon (C) is introduced. The value of the concentration of the hydrophobizing substance 80 to be introduced may be, for example, 10 ¹⁵ to 10 ¹⁶ Atoms / cm ² for atoms such as silicon and carbon.

As a result, the surfaces of the susceptor 22 and the susceptor 32 become hydrophobic due to the presence of the hydrophobizing substance 80, and the affinity (bonding strength) with the etching reaction product 72 of the same hydrophobicity is increased. As a result, it is possible to prevent the etching reaction product 72 attached to the susceptor 22 and the susceptor 32 from peeling off.

Hereinafter, an example of the operation of the dry etching apparatus according to the present embodiment will be described.

First, the semiconductor wafer W is carried into the processing chamber 10 directly above the lower electrode 20 through the gate valve 50, and is placed on the wafer push-up pins 23 projecting from the lower electrode 20. Thereafter, the semiconductor wafer W is placed on the electrostatic chuck 21 by lowering the wafer lifting pins 23, and is fixed by electrostatic suction.

Next, the inside of the processing chamber 10 is
The reaction gas 71 is introduced while evacuating to a desired degree of vacuum, and high-frequency power is applied between the lower electrode 20 and the upper electrode 30 from the high-frequency power supply 40, so that the lower electrode 20 and the upper electrode 30 Plasma of the reaction gas 71 is formed in the space between the two, and an oxide film or the like formed on the surface of the semiconductor wafer W is etched. Then, the semiconductor wafer W after the completion of the etching is carried out in a procedure reverse to the carrying-in.

Here, in the above-mentioned etching process,
As the etching reaction progresses, an etching reaction product 72 generated is formed on the inner wall of the processing chamber
And susceptor 2 arranged around upper electrode 30
2 and the susceptor 32. In particular, the susceptor 22 and the susceptor 3 existing near the semiconductor wafer W
The etching reaction product 72 attached to 2 has a high possibility of becoming a foreign substance when detached and attaching to the semiconductor wafer W.

However, as described above, in the case of the present embodiment, the susceptor 22 and the susceptor 32 are rendered hydrophobic by the presence of the hydrophobizing substance 80 introduced to the surface. It has a high affinity with the etching reaction product 72 of the same hydrophobicity, and the etching reaction product 7
2 has an increased adhesive strength to the susceptor 22 and the susceptor 32, and the etching reaction product 72
In addition, the semiconductor wafer W is hardly peeled off from the susceptor 32, so that the amount of foreign matter attached to the semiconductor wafer W can be significantly reduced. As a result, the occurrence of defects such as circuit patterns constituting the semiconductor device formed on the semiconductor wafer W is reduced, and the yield is reliably improved.

The effect of reducing the amount of foreign matter generated by the susceptor 22 and the susceptor 32 according to the present embodiment is based on the amount of the etching reaction product 72 attached to the susceptor 22 and the susceptor 32 in the process of processing a plurality of semiconductor wafers W. Therefore, the frequency of performing long-term maintenance management work such as opening the inside of the processing chamber 10 to the atmosphere and cleaning the processing chamber 10 for the purpose of reducing foreign substances caused by the etching reaction products 72 is reduced. As a result, it is possible to improve the operation rate and the throughput of the dry etching apparatus.

The method of making the surfaces of the susceptor 22 and the susceptor 32 hydrophobic is not limited to the method illustrated in FIG. 2. For example, a bipolar molecule 90 made of alcohols such as polyvinyl alcohol may be used. Evaporation or coating or LB (Langmuir-Blodget)
The susceptor 22 and the susceptor 32 are attached to the surface of the susceptor 22 and the susceptor 32 by a technique such as a method.
The surface may be made hydrophobic.

That is, a bipolar molecule 90 composed of a hydrophilic molecule (hydrophilic group) and a hydrophobic molecule (hydrophobic group) is placed on the side of the hydrophilic molecule, and a susceptor 22 composed of the same hydrophilic quartz,
Adsorbed on the surface of the susceptor 32, the hydrophobic molecules on the opposite side cover the surfaces of the susceptor 22 and the susceptor 32. As a result, the surfaces of the susceptor 22 and the susceptor 32 covered with the bipolar molecule 90 exhibit the same hydrophobicity as the etching reaction product 72, and the etching reaction product 7
2, the adhesion to the surfaces of the susceptor 22 and the susceptor 32 is increased, and the generation of foreign matter adhered to the semiconductor wafer W due to the peeling of the etching reaction product 72 is reduced, so that the yield can be prevented from being reduced due to the foreign matter. Become.

(Embodiment 2) FIG. 4 is a flowchart showing an example of a dry etching method according to an embodiment of the present invention. In this embodiment, the same dry etching apparatus as that in the first embodiment is used. In the case of the second embodiment, for example, a desired release agent is applied to the surfaces of susceptor 22 and susceptor 32 where there is a concern that foreign matter may be generated due to separation of etching reaction product 72, and for example, 1 Each time one semiconductor wafer W is processed, an operation of removing the etching reaction product 72 attached to the susceptor 22 and the susceptor 32 is performed. This removal operation is performed as part of a normal etching process without opening the processing chamber 10 to the atmosphere. Accordingly, it is possible to reduce the generation of foreign matter due to an increase in the amount of the etching reaction product 72 attached to the surfaces of the susceptor 22 and the susceptor 32.

That is, first, a desired release agent is applied to the surfaces of the susceptor 22 and the susceptor 32 (step 100).

Thereafter, the semiconductor wafer W is loaded into the processing chamber 10 (Step 101).

Next, inside the processing chamber 10, the semiconductor wafer W
Is performed (step 102).

Next, the semiconductor wafer W is carried out of the processing chamber 10 (Step 103).

Next, an operation for peeling and removing the etching reaction product 72 from the surfaces of the susceptor 22 and the susceptor 32 in the processing chamber 10 is performed (step 104). At this time, since the release agent is previously applied to the surfaces of the susceptor 22 and the susceptor 32, the removal of the etching reaction product 72 can be easily, quickly and reliably performed.

This operation is repeated for each semiconductor wafer W (step 105).

As described above, in the case of the second embodiment,
At the start of the etching process for each semiconductor wafer W,
Since the surfaces of the susceptor 22 and the susceptor 32 are cleaned, it is possible to reliably prevent foreign matter from adhering to the semiconductor wafer W due to accumulation and separation of the etching reaction products 72 on the surfaces of the susceptor 22 and the susceptor 32. Thus, the yield of semiconductor devices formed on the semiconductor wafer W can be improved. Further, since there is no need to perform a large-scale and time-consuming maintenance management work such as opening to the atmosphere, the throughput is also improved.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and can be variously modified without departing from the gist thereof. Needless to say, there is.

For example, in the above-described embodiment, the case where the surface of the susceptor located near the semiconductor wafer is made hydrophobic is described as an example. However, if necessary, the inner wall surface of the processing chamber may be made hydrophobic. Are also included in the present invention.

[0042]

Advantageous effects obtained by typical ones of the inventions disclosed in the present application will be briefly described.
It is as follows.

According to the dry etching apparatus of the present invention,
The effect of reducing foreign substances adhering to the semiconductor wafer can be obtained.

According to the dry etching apparatus of the present invention,
This has the effect of reducing the occurrence of defects due to the attachment of foreign matter to the semiconductor wafer and improving the yield of semiconductor devices formed on the semiconductor wafer.

According to the dry etching apparatus of the present invention,
The effect is obtained that foreign substances adhering to the semiconductor wafer can be reduced without lowering the throughput.

According to the dry etching method of the present invention,
The effect of reducing foreign substances adhering to the semiconductor wafer can be obtained.

According to the dry etching method of the present invention,
This has the effect of reducing the occurrence of defects due to the attachment of foreign matter to the semiconductor wafer and improving the yield of semiconductor devices formed on the semiconductor wafer.

According to the dry etching method of the present invention,
The effect is obtained that foreign substances adhering to the semiconductor wafer can be reduced without lowering the throughput.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of the structure of a dry etching apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view schematically illustrating a part of a dry etching apparatus according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically illustrating a part of a dry etching apparatus according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an example of a dry etching method according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view schematically illustrating an example of an attached state of a susceptor and a reaction product in a normal quartz state.

[Explanation of symbols]

 Reference Signs List 10 processing chamber 20 lower electrode (first electrode) 21 electrostatic chuck 22 susceptor 23 wafer push-up pin 30 upper electrode (second electrode) 31 electrode substrate 32 susceptor 40 high-frequency power supply 50 gate valve 60 exhaust port 70 gas supply mechanism 71 Reaction gas 72 Etching reaction product 80 Hydrophobizing substance 90 Bipolar molecule W Semiconductor wafer

Claims (7)

[Claims] 1. A dry etching apparatus for performing dry etching on a semiconductor wafer by supplying a reactive gas into a processing chamber containing a semiconductor wafer therein, wherein the component is exposed to the reactive gas. A dry etching apparatus characterized in that the surface of the substrate is made hydrophobic. 2. The dry etching apparatus according to claim 1, wherein a first electrode on which the semiconductor wafer is mounted and a second electrode disposed opposite to the first electrode are provided inside the processing chamber. A dry etching apparatus comprising: two electrodes; and a susceptor disposed around at least one of the first and second electrodes, wherein a surface of the susceptor is selectively made hydrophobic. 3. The dry etching apparatus according to claim 2, wherein the susceptor is made of quartz, and a hydrophobic substance is present at a desired concentration on the surface of the susceptor by ion implantation or diffusion. Is a dry etching device characterized by being made hydrophobic. 4. The susceptor according to claim 2, wherein a bipolar molecule having a hydrophilic group and a hydrophobic group is attached to the surface of the susceptor by vacuum deposition, coating, or LB method. A dry etching apparatus characterized in that the surface of the substrate is made hydrophobic. 5. The dry etching apparatus according to claim 3, wherein said hydrophobic substance comprises silicon atoms or carbon atoms. 6. The dry etching apparatus according to claim 4, wherein said bipolar molecules are made of alcohols. 7. A dry etching method for performing dry etching on a semiconductor wafer by supplying a reactive gas into a processing chamber containing a semiconductor wafer therein, wherein the reactive gas is provided inside the processing chamber. Depositing a release agent on the surface of the component exposed to the substrate, loading the semiconductor wafer into the processing chamber and performing dry etching on the semiconductor wafer, and unloading the semiconductor wafer from the processing chamber. And a step of removing a reaction product attached to the surface of the component member.