JPS63133530A - Ashing - Google Patents

Abstract

PURPOSE:To make ashing gas flow out uniformly through a flowing-out port and to make possible a uniform treatment by a method wherein the center of the point of the flowingout port to a substrate to be treated for the ashing gas is set on the central axis of the substrate to be treated and the size of the flowing-out port is made smaller than that of the substrate to be treated. CONSTITUTION:A chamber 2 is descended to couple with a lower chamber 4 and the interior of a treating chamber is held in a sealed state. At this time, a disc 10 formed of glass, for example, is provided in such a way as to be positioned at a position separated at an interval of 0.5-20 mm or thereabouts, for example, from the surface of a semiconductor wafer 7 and the center of the point of a flowing-out port 3 is provided in such a way as to be positioned on the central axes of a placing stand 6 and the semiconductor wafer 7. Ashing gas is flowed out through the flowing- out port 3 penetrated in a diameter of 20-40 mm or thereabouts, for example, at the central part of the disc 10 via a nozzle 15 being continuously connected to an ozone generator 9 through an upper chamber 2. A diffusing part 16 provided with a plurality of small holes 17 of 0.01-5 mm or thereabouts, for example, is provided at the connecting part of this nozzle 15 and the flowing-out port 3, the ashing gas is made to flow out more uniformly to the surface of the wafer 7 and the uniformity of an ashing treatment in the whole surface of the wafer is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ashing method for ashing a film deposited on a substrate to be processed.

(Prior Art) Generally, fine patterns for semiconductor integrated circuits are formed by etching a base film formed on a semiconductor wafer using an organic polymer photoresist film formed by exposure and development as a mask. Therefore, the photoresist film used as a mask must be removed from the surface of the semiconductor wafer after the etching process.

Ashing processing is performed to remove the photoresist film in such cases.

An example of this is disclosed in Japanese Unexamined Patent Publication No. 52-20766.

According to this publication, in order to uniformly diffuse ashing gas onto the semiconductor wafer and flow it out, a diffusion plate having multiple openings and having a diameter equal to or larger than that of the wafer is placed parallel to and close above the semiconductor wafer. A configuration is disclosed in which an ashing process is performed by uniformly flowing ashing gas onto a semiconductor wafer through a plate.

(Problems to be Solved by the Invention) In the above-mentioned mechanism, a plurality of outflow ports for the ashing gas to the semiconductor wafer are formed, and when the ashing gas flows out onto the semiconductor wafer from the outflow ports, the diffusion plate and the wafer come close to each other. Therefore, there is a problem in that the ashing gas does not come into uniform contact with the entire surface of the semiconductor wafer, resulting in uneven ashing. Furthermore, there is a problem in that the ashing gas adheres to the diffusion plates that are disposed in close opposition to each other.

The present invention has been made to address the above-mentioned problems, and provides an ashing method that allows ashing gas to flow uniformly onto a substrate to be processed, thereby performing a uniform ashing process.

[Structure of the invention]

(Means for Solving the Problems) The present invention is characterized in that the center of the tip of the outlet of the ashing gas to the substrate to be processed is set on the central axis of the substrate to be processed. The size of the outlet is smaller than the size of the substrate to be processed.

(Function) In the ashing method of the present invention, since the center of the tip of the outlet of the ashing gas to the substrate to be processed is set on the central axis of the substrate to be processed, the ashing gas flows uniformly from the outlet onto the substrate to be processed. This makes it possible to perform a uniform ashing process without uneven ashing.

(Example) Hereinafter, an example in which the method of the present invention is applied to an ashing process in a semiconductor manufacturing process will be described with reference to the drawings.

A cylindrical upper chamber 2 with a U-shaped cross section is provided so as to be movable up and down by a lifting mechanism 1. The central axis of the upper chamber 2 has an outlet 3 for letting out the ashing gas.
For example, a cylindrical nozzle with a diameter of 8 m is provided. A disk 10 is provided on the same surface formed by the tip of this nozzle. A lower chamber 4 is provided to engage with the upper chamber 2, and within this chamber 4 is provided a disk-shaped mounting table 6 for semiconductor wafers whose temperature can be freely controlled by a temperature control mechanism 5. . A substrate to be processed, such as a semiconductor wafer 7, is set on the mounting table 6. This wafer 7
An ozone generator 9 equipped with an oxygen supply source 8 is disposed so as to irradiate the surface with 7 shinging gas. The ashing gas is caused to flow out from the outlet 3 onto the surface of the wafer 7. The disk 1 is placed parallel to the semiconductor wafer 7 placed a on the mounting table 6 in order to ash the film on the surface of the semiconductor wafer 7.
For example, glass plates are provided at equal intervals around the center.

After the ashing process, the ashing gas is decomposed by an ozone decomposer (not shown) and exhausted by the exhaust mechanism 11. The ashing gas flow path inside the nozzle has
The tip of the nozzle 6 has a built-in diffuser plate provided with a large number of openings for diffusing this gas, and has a fan-shaped cross section.

Next, a method of ashing a semiconductor wafer using the above-described ashing apparatus will be described.

The upper chamber 2 is raised by the lifting mechanism 1, and the substrate to be processed, such as a semiconductor wafer 7, is automatically moved to a predetermined position t on the mounting table 6 installed inside the lower chamber 4 by a transport mechanism (not shown). Transport and place. By aligning the orientation flat of the wafer 7 as necessary, devices with the same characteristics can be manufactured with good reproducibility.

Next, the chamber 2 is lowered and connected to the lower chamber 4 to seal the inside of the processing chamber.

At this time, the disk 1o made of glass, for example, is placed at a distance of, for example, about 0.5 to 20 nwn from the surface of the semiconductor wafer 7. Further, the outlet 3 is provided so that the center of the tip thereof is located on the central axis of the mounting table 6 and the semiconductor wafer 7.

Uniform treatment is possible over the entire surface of the wafer 7.

In this case, a center positioning mechanism as shown in FIG. 2 is provided before the ashing processing chamber, and the semiconductor wafer 7 is mounted on a plurality of belts made of silicone rubber, for example, embedded in a base 12 made of aluminum, for example. 13 and comes into contact with a center alignment guide 14 made of, for example, Teflon, at which point alignment of the center of the semiconductor wafer 7 is completed. A center positioning guide is provided so that the center position is aligned when the semiconductor wafer 7 comes into contact with the semiconductor wafer 7.

This mechanism is not limited to being provided before the ashing processing chamber, but may be provided within the ashing processing chamber.

With such a mechanism, the center of the semiconductor wafer 7 is aligned, and the center of the mounting table 6 and the center of the semiconductor wafer 7 are aligned and placed a by a transport mechanism such as a hand arm. Thereafter, ashing gas generated by an ozone generator 9 equipped with an oxygen supply source 8 is diffused by a diffusion plate in the nozzle and flows out onto the surface of the wafer 7 from an outlet 3 provided at the center of the disk lO.

At this time, the wafer 7 has already been placed on the mounting table 6 by the temperature control mechanism 5.
It is heated to, for example, about 300'C by a heater installed inside. The configuration of the above nozzle and diffusion plate is as follows. That is, as shown in FIG. 3, the disc 10 is made of a glass with low thermal conductivity, such as Pyrex, with a diameter of 20 to 40 Il in the center thereof.
The upper chamber 2 is connected to the outlet 3 which penetrates in a circular shape about I11.
For example, the ozone generator 9 is connected to the ozone generator 9 via the
A nozzle 15 formed of an aluminum tube of about 30 nm is connected, and the ashing gas flows out from the outlet 3 through the nozzle 15. At the connection between the nozzle 15 and the outlet 3, there are a plurality of small holes 1 having a diameter of about 0.01 to 5 m, for example, as shown in FIG.
The ashing gas diffusion section 16 made of aluminum and having a diameter of about 2 to 30 mm is provided. This diffusion section 16 allows the ashing gas to flow more uniformly onto the surface of the semiconductor wafer 7 placed on the mounting table 6. If the ashing gas flows out without providing the diffusion section 16, the ashing gas will flow out over the entire surface of the wafer. The uniformity of the ashing process decreases.

The ashing gas is uniformly discharged radially from the center of the semiconductor wafer 7 onto the surface of the semiconductor wafer 7 placed on the mounting table 6 through the outlet 3, thereby performing an ashing process on the semiconductor wafer 7.

The ashing gas after the ashing process is decomposed by an ozone decomposer 9 (not shown) and exhausted from the exhaust mechanism 11.

The ashing process for the semiconductor wafer 7 is thus completed, and the semiconductor wafer 7 is transported to the next process by a transport mechanism (not shown).

In the above embodiment, Pyrex is used as the material for the one circular plate IO, but any heat-resistant glass may be used, and quartz glass may also be used.

Further, if the diameter of the ashing gas disk is larger than the semiconductor wafer, it may be equal to the inner diameter of the upper chamber, and may be large enough to close the upper chamber. Furthermore, the size of the outlet is smaller than the size of the semiconductor wafer6. Although the center positioning mechanism of the semiconductor wafer was performed using the center positioning mechanism described above, the present invention is not limited to the above-described mechanism as long as the center of the semiconductor wafer and the center of the mounting table are aligned.

As described above, according to this embodiment, the center of the semiconductor wafer is aligned with the center of the mounting table, and the outlet is provided on the central axis, so that the ashing gas can flow uniformly over the semiconductor wafer. I can do it.

Furthermore, since heat-resistant glass with low thermal conductivity is used, the temperature of the ashing gas does not decrease.

Furthermore, the use of this glass prevents the occurrence of contamination.

〔Effect of the invention〕

As explained above, according to the present invention, since the center of the tip of the outlet of the ashing gas to the substrate to be processed is set on the central axis of the substrate to be processed, the ashing gas is uniformly distributed from the center of the substrate to the periphery. This makes it possible to perform a uniform ashing process. Further, since an opening smaller than the above-mentioned outlet is provided in the outlet for the ashing gas to the substrate to be processed, it becomes possible for the ashing gas to flow out more uniformly over the substrate to be processed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the ashing apparatus in the ashing method of the present invention, FIG. 2 is a block diagram of the center positioning mechanism for the substrate to be processed in FIG. 1, and FIG. 3 is the ashing gas outlet circle in FIG. 1. The block diagram of the plate, FIG. 4, is a block diagram of the diffusion section provided in the ashing gas outflow nozzle of FIG. 1. 3... Outlet, 10... Disc, 14...
Center positioning guide, 15... Nozzle, 16...
・Diffusion part, 17...Small hole Applicant Tokyo Electron Ltd. Figure 1 Figure 3 Figure 4

Claims (3)

[Claims] (1) In an ashing method in which a film deposited on a substrate to be processed is ashed with an ashing gas, an outflow port having a size smaller than the substrate to be processed, whose tip center is set on the central axis of the substrate to be processed, is used. An ashing method characterized in that the ashing gas is caused to flow toward the substrate to be processed. (2) The ashing gas outlet is provided with a large number of openings smaller than the outlet, and the ashing gas is diffused through the large number of openings.
Ashing method described in section. (3) The ashing gas is irradiated onto the substrate to be processed through a single nozzle, and an ashing gas diffusion plate having a large number of openings is provided in the nozzle. ashing method.