JP2000223474A - Ashing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ashing system excellent in resist stripping performance in which generation of residual resist can be prevented. SOLUTION: An ashing system comprises a vacuum chamber 2, a wafer mounting table 10 disposed in the vacuum chamber 2, and a plasma generating chamber 3 disposed above the wafer mounting table 10 wherein radicals r in plasma P generated in the plasma generating chamber 3 down flows onto the wafer mounting face 10a of the wafer mounting table 10. In such an ashing system, a plurality of straightening fins 11 are provided on the side circumference of the wafer mounting table 10 while extending outer downward from the circumferential edge of the wafer mounting face 10a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ashing apparatus, and more particularly, to an ashing apparatus used for removing a resist on a wafer in a semiconductor device manufacturing process.

[0002]

2. Description of the Related Art FIG. 4 shows a configuration diagram of a main part of an ashing apparatus. The ashing apparatus shown in FIG. 1 includes a vacuum chamber 2 in which a wafer mounting table 1 for mounting a wafer W is provided, and a plasma provided above the wafer mounting table 1 in a state of communicating with the vacuum chamber 2. And a generation chamber 3. A vacuum pump 4 is connected to the bottom of the vacuum chamber 2 so that the gas inside the vacuum chamber 2 can be exhausted. The wafer mounting table 1 provided in the vacuum chamber 2 has, for example, a columnar shape, and has a temperature control unit such as a heater therein. A gas introduction pipe 5 is connected to the upper part of the plasma generation chamber 3, and a coil 6 is wound therearound.

In the ashing apparatus having such a configuration, after the wafer W is mounted on the wafer mounting table 1 and the gas in the vacuum chamber 2 is exhausted, the ashing gas is supplied from the gas introduction pipe 5 into the plasma generation chamber 3. RF into coil 6 with introduced
An electric current is supplied to generate plasma P in the plasma generation chamber 3. The radicals r in the plasma P are supplied to the wafer mounting table 1 in the vacuum chamber 2 in a downflow manner, whereby the resist on the surface of the wafer W is removed by ashing.

[0004]

However, the ashing device having the above configuration has the following problems. That is, as shown in FIG. 5, in the ashing process, when radicals r in the plasma P are supplied to the resist R on the surface of the wafer W, the resist R reacts with the radicals r to generate a reaction gas g, and the resist R Is released and removed as a reaction gas g. Here, as shown in FIG. 6, most of the released reaction gas g is removed from the inside of the vacuum chamber by the vacuum pump, but some of the reaction gas g adheres to the surface of the wafer W without being removed. Solidifies. In the ashing process, vapor phase growth using the solidified substance as a nucleus proceeds, and remains as a resist residue on the wafer W.
This resist residue is very difficult to peel off, and causes pattern defects in subsequent pattern formation and the like.

Further, in an atmosphere in which a large amount of the reaction gas g is generated, supply of new radicals tends to be insufficient, and there is a problem that the reaction between the resist and the radicals is reduced and the peeling characteristic of the resist is deteriorated.

Accordingly, an object of the present invention is to provide an ashing apparatus which can prevent the generation of a resist residue and has excellent resist peeling characteristics.

[0007]

According to a first aspect of the present invention, there is provided a vacuum chamber, a wafer mounting table provided in the vacuum chamber, and a wafer mounting table provided above the wafer mounting table. An ashing apparatus comprising: a plasma generation chamber; and a plasma generated in the plasma generation chamber, wherein plasma generated in the plasma generation chamber is down-flowed onto a wafer mounting surface of the wafer mounting table. A plurality of rectifying fins extending downward from the periphery of the fin are provided.

[0008] In the ashing apparatus having such a configuration, a plurality of rectifying fins extending downward from the periphery of the wafer mounting surface to the outside are provided on the wear mounting table, so that the plasma is generated from the plasma generation chamber to the wafer mounting surface. When the flow is performed, an airflow is formed from the wafer mounting surface to the outside along the extending direction of the rectifying fins. Therefore, when an ashing process is performed by mounting a wafer on the wafer mounting table, the reaction gas generated by the reaction between the plasma and the resist on the wafer surface quickly moves to the outside of the wafer mounting table along the gas flow. Be guided. Then, new plasma is promptly supplied to the wafer portion from which the reaction gas has been removed.

According to a second aspect of the present invention, there is provided a vacuum chamber, a wafer mounting table provided in the vacuum chamber, and a plasma generation chamber provided above the wafer mounting table. In the ashing apparatus for causing the plasma generated in the downflow on the wafer mounting surface of the wafer mounting table, between the plasma generating chamber and the wafer mounting table, the plasma mounting chamber side of the wafer mounting table A fan for forming an airflow toward the wafer mounting surface side is provided.

In the ashing apparatus having such a configuration, a fan is provided between the plasma generation chamber and the wafer mounting table to form an airflow from the plasma generation chamber to the wafer mounting surface of the wafer mounting table. As a result, the airflow that has reached the wafer mounting surface is further directed to the outside of the wafer mounting surface. Therefore, when an ashing process is performed by mounting a wafer on the wafer mounting table, the reaction gas generated by the reaction between the plasma and the resist on the wafer surface quickly moves to the outside of the wafer mounting table along the gas flow. Be guided. Then, new plasma is promptly supplied to the wafer portion from which the reaction gas has been removed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment to which an ashing device of the present invention is applied will be described below with reference to the drawings. Note that the same components as those of the conventional ashing device described with reference to FIG.

(First Embodiment) FIG. 1 is an overall configuration diagram for explaining an embodiment of an ashing apparatus to which the invention of claim 1 is applied, and the invention of claim 1 will be described with reference to FIG. A first embodiment to which the present invention is applied will be described. The ashing device shown in FIG. 1 is an RF downflow type ashing device, which includes a vacuum chamber 2 and a plasma generation chamber 3 provided in communication with the vacuum chamber 2. The wafer transfer chamber 7 is connected via a gate valve 7a.

A vacuum pump 4 is connected to the bottom of the vacuum chamber 2 so that the gas inside the vacuum chamber 2 can be exhausted.

In the vacuum chamber 2, a wafer mounting table 10 characteristic of this embodiment is provided. The wafer mounting table 10 has a temperature control means (not shown) such as a heater inside a cylindrical main body, for example, and is characterized in that a plurality of rectifying fins 11 are provided on the side circumference. These rectifying fins 11 extend from the peripheral edge of the wafer mounting surface 10a of the wafer mounting table 10 to the outside and downward. The number of the rectifying fins 11, the spacing between the rectifying fins 11, and the shape and size of each of the rectifying fins 11 are set such that an airflow is uniformly formed over the entire surface of the wafer W on the wafer mounting surface 10a. It will be selected appropriately.

Further, a gas introduction pipe 5 is connected to an upper portion of the plasma generation chamber 3 provided on the wafer mounting table 10, and a coil 6 is wound therearound.

A transfer arm 8 is provided in the wafer transfer chamber 7. The transfer arm 8 is for loading and unloading the wafer W between the wafer mounting table 10 in the vacuum chamber 2 and the wafer carrier 9 in the wafer transfer chamber 7.

Ashing removal of the resist on the surface of the wafer W using the ashing apparatus having such a configuration is performed as follows. First, the wafer carrier 9 containing the wafer W is inserted into the wafer transfer chamber 7, and the gate valve 7a is opened to open the wafer W contained in the wafer carrier 9.
Is mounted on the wafer mounting table 10 using the transfer arm 8. Next, the gate valve 7a is closed, the inside of the vacuum chamber 2 is evacuated to a predetermined pressure by the vacuum pump 4, and the wafer mounting table 10 is controlled by the temperature control means of the wafer mounting table 10.
The wafer W mounted thereon is heated to a predetermined temperature. Thereafter, an ashing gas is introduced from the gas introduction pipe 5 into the plasma generation chamber 3 and an RF current flows through the coil 6, thereby generating a plasma P of the ashing gas in the plasma generation chamber 3. The ashing gas is appropriately selected from oxygen, a gas obtained by adding a fluorine-based gas to oxygen, a hydrogen-based gas, and the like. Then, the radicals r in the generated plasma P are caused to flow down to the wafer mounting table 10 side, and the radicals r remove ashing on the surface of the wafer W mounted on the wafer mounting table 10 by ashing.

In the ashing apparatus having the above-mentioned structure operated as described above, the plurality of rectifying fins 11 extending downward from the peripheral edge of the wafer mounting surface 10a to the outside of the wear mounting table 1a.
0, the radicals r in the plasma P are caused to flow down from the plasma generation chamber 3 to the wafer mounting surface 10a, and the wafer mounting surface 1 along the rectifying fins 11.
An airflow is formed from the center of Oa toward the outside.
For this reason, the reaction gas generated by the reaction between the radical r and the resist on the surface of the wafer W is quickly guided to the outside of the wafer mounting table 10 along with this gas flow. Then, new radicals r are promptly supplied from the plasma generation chamber 3 to the wafer portion from which the reaction gas has been removed.

As a result, it is possible to prevent the reactive gas from re-adhering to the surface of the wafer W, so that it is possible to prevent the generation of a resist residue due to the re-adhered substance and to prevent radicals r from adhering to the surface of the wafer W. Can be activated, so that the resist stripping characteristics can be improved. In addition, since it is possible to form an airflow that goes outward from the center of the wafer mounting surface 10a without increasing the gas flow rate, the above-described process gas (i.e., ashing gas) is not wastefully used. The effect can be obtained.

(Second Embodiment) FIG. 2 is a configuration diagram for explaining an embodiment of an ashing device to which the invention of claim 2 is applied. The invention of claim 2 will be described below with reference to FIG. A second embodiment to which the present invention is applied will be described. Note that the same components as those of the ashing device of the first embodiment described with reference to FIG. 1 are denoted by the same reference numerals, and redundant description will be omitted.

The ashing device of the second embodiment shown in FIG. 2 is different from the ashing device of the first embodiment in that a fan 20 is provided between the plasma generation chamber 3 and the wafer mounting table 1. . Further, the wafer mounting table 1 is also assumed to be of a columnar shape different from the wafer mounting table (10) with the rectifying fins of the first embodiment.

Here, the fan 20 provided between the plasma generation chamber 3 and the wafer mounting table 1
It is installed, for example, directly above the wafer mounting surface 1a, preferably in parallel with the wafer mounting surface 1a, so as to form an airflow from the side toward the wafer mounting surface 1a of the wafer mounting table 1. . By setting the fan 20 parallel to the wafer mounting surface 1a, the wafer W mounted on the wafer mounting surface 1a
So that an airflow is uniformly formed over the entire surface.

As shown in FIG. 3, the distance d between the blades 21 constituting the fan 20 is increased as much as
Reduce the area covered. This prevents the supply of the radical r supplied from the plasma generation chamber 3 shown in FIG. 2 to the wafer mounting surface 1a side from being hindered. The distance d is appropriately adjusted depending on the shape and the mounting state of the wing 21. Further, in order to form a sufficient airflow over the entire surface of the wafer W mounted on the wafer mounting table 1, the entire size of the fan 20 should be approximately equal to or larger than the diameter of the wafer W. Is desirable.

The fan 20 has a resistance to the radicals r supplied from the plasma generation chamber 3 and is made of a material which does not become a contamination source for the wafer W. As such a material, for example, sapphire-coated quartz is preferably used.

In order to remove the resist on the surface of the wafer W by ashing using the ashing apparatus having such a configuration, radicals r in the plasma P are removed by the same procedure as described in the first embodiment. At the time of downflow to the first side, the fan 20 is operated to form an airflow from the plasma generation chamber 3 toward the wafer mounting surface 1a.

In the ashing apparatus having the above-mentioned structure operated in this manner, a fan 20 is provided between the plasma generation chamber 3 and the wafer mounting table 1 so that the wafer mounting surface 1a of the wafer mounting table 1 is provided from the plasma generation chamber 3 side. By forming the airflow toward the side, the airflow that has reached the wafer mounting surface 1a further flows outward from the center side of the wafer mounting surface 1a. For this reason, the reaction gas generated by the reaction between the radical r and the resist on the surface of the wafer W is quickly guided to the outside of the wafer mounting table 1 by carrying this gas flow. Then, new radicals r are promptly supplied to the wafer portion from which the reaction gas has been removed.

As a result, it is possible to prevent the reactive gas from re-adhering to the surface of the wafer W, so that it is possible to prevent the generation of the resist residue due to the re-adhering, and to prevent the radicals r from adhering to the surface of the wafer W. Since the supply can be activated, the stripping characteristics of the resist can be improved. Moreover, since it is possible to form an air flow directed outward from the center of the wafer mounting surface 1a without increasing the gas flow rate, the process gas (i.e., the ashing gas) is not wasted, and The effect can be obtained.

The ashing device of the second embodiment may use a wafer mounting table provided with a rectifying fin provided in the ashing device of the first embodiment. In such a case, since an airflow from the center side of the wafer mounting surface to the outside is more likely to be formed, the effect of preventing the generation of resist residues and the effect of improving the resist peeling characteristics are further improved. Can be achieved.

[0029]

As described above, according to the first aspect of the present invention,
According to the ashing device described above, a plurality of rectifying fins extending downward from the peripheral edge of the wafer mounting surface to the outside are provided on the wear mounting table, so that the airflow from the center side of the wafer mounting surface to the outside is reduced. It can be formed. For this reason, the reaction gas generated at the time of stripping the resist can be quickly guided to the outside of the wafer mounting table. As a result, it is possible to prevent the reaction gas from re-adhering to the wafer surface, thereby preventing the generation of resist residues, and to activate the supply of plasma to the wafer surface, thereby improving the resist peeling characteristics. Becomes possible.

According to the ashing apparatus of the second aspect, a fan for forming an airflow from the plasma generation chamber side to the wafer mounting surface side is provided between the plasma generation chamber and the wafer mounting table. With this configuration, it is possible to form an airflow from the plasma generation chamber through the wafer mounting surface and further outward from the center of the wafer mounting surface. For this reason, the reaction gas generated at the time of stripping the resist can be quickly guided to the outside of the wafer mounting table. As a result, it is possible to prevent the reaction gas from re-adhering to the wafer surface, thereby preventing the generation of resist residues, and to activate the supply of plasma to the wafer surface, thereby improving the resist peeling characteristics. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of an ashing device according to a first embodiment.

FIG. 2 is a configuration diagram illustrating an example of an ashing device according to a second embodiment.

FIG. 3 is a plan view illustrating a configuration of a fan of an ashing device according to a second embodiment.

FIG. 4 is a configuration diagram showing a conventional ashing device.

FIG. 5 is a diagram illustrating ashing removal of a resist in an ashing apparatus.

FIG. 6 is a diagram illustrating a problem of a conventional ashing device.

[Explanation of symbols]

1, 10: wafer mounting table, 1a, 10a: wafer mounting surface, 2: vacuum chamber, 3, plasma generation chamber, 11: rectifying fin, 20: fan, P: plasma

Claims (2)

[Claims] A vacuum chamber, a wafer mounting table provided in the vacuum chamber, and a plasma generation chamber provided above the wafer mounting table, wherein plasma generated in the plasma generation chamber is supplied to the wafer generation chamber. An ashing apparatus for down-flowing on a wafer mounting surface of a mounting table, wherein a plurality of rectifying fins extending downward from the periphery of the wafer mounting surface to the outside are provided on a side circumference of the wafer mounting table. Ashing device. 2. A vacuum chamber, a wafer mounting table provided in the vacuum chamber, and a plasma generation chamber provided above the wafer mounting table, wherein plasma generated in the plasma generation chamber is supplied to the wafer by the plasma generation chamber. An ashing apparatus for down-flowing on a wafer mounting surface of a mounting table, wherein an air current flowing between the plasma generation chamber and the wafer mounting table from the plasma generation chamber side toward the wafer mounting surface side of the wafer mounting table. An ashing device, wherein a fan for forming the fin is provided.