JPS6343322A - Ashing equipment - Google Patents

Abstract

PURPOSE:To perform a high-speed and uniform ashing by providing a planar gas outlet closely opposed to a wafer, a cooling mechanism disposed in this opposed portion, and a wafer heating device. CONSTITUTION:A diffusion board 17c of a gas outlet 17 is disposed close to a semiconductor wafer 12, and O3 is caused to flow out to supply new O3 to the wafer surface, thereby facilitating the oxidation reaction between the oxygen atom radicals and the film deposited on the wafer. A cooling pipe 18a is provided in the diffusion board 17c and cooling is provided by a device 18, and the diffusion board 17c is kept at a low temperature against the wafer 12 heated by a heater 15, thereby suppressing the decomposition of O3. The gas flow from the diffusion board 17c is heated by the heated wafer and the atmosphere around it and is decomposed to generate a large amount of oxygen atom radicals, thereby enabling a high-speed and uniform ashing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an ashing device that oxidizes and removes a photoresist film or the like deposited on a semiconductor wafer using ozone.

(Prior Art) Formation of fine patterns in semiconductor integrated circuits is generally performed by etching a base film formed on a semiconductor wafer using an organic polymer photoresist film formed by exposure and development as a mask. It will be done.

The photoresist film previously 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.

This ashing process is used to remove resist, clean silicon wafers and masks, as well as remove ink, solvent residue, etc., and is suitable for dry cleaning in semiconductor processes.

As an ashing device for removing a photoresist film, one that uses oxygen plasma is generally used.

Oxygen plasma ashing equipment for photoresist films places a semiconductor wafer with a photoresist film in a processing chamber, turns the oxygen gas introduced into the processing chamber into plasma using a high-frequency electric field, and generates oxygen atomic radicals that remove organic substances. Nikaku carbon with phytoresist film as core, −
Removed by decomposition into carbon oxide and water.

Furthermore, there is an ashing device that performs ashing processing in badge processing by generating oxygen atom radicals by irradiating ultraviolet rays.

Figure 17 shows an ashing device that prevents the generation of oxygen atom radicals through ultraviolet irradiation.
In this process, a large number of semiconductor wafers 2 are vertically arranged at predetermined intervals, and ultraviolet light from an ultraviolet light emitting tube 3 installed at the top of the processing chamber 1 is transmitted to a transparent material such as quartz installed on the top surface of the processing chamber 1. irradiation through a window 11 to excite oxygen filled in the processing chamber 1 and generate ozone. Oxygen atom radicals generated from this ozone atmosphere act on the semiconductor wafer 2 to perform an ashing process.

(Problems to be Solved by the Invention) However, among the conventional ashing devices described above,
An ashing device using oxygen plasma is used to irradiate a semiconductor wafer with ions and electrons accelerated by the electric field existing in the plasma.
There is a problem of giving j.

In addition, in the case of an ashing device using ultraviolet rays, the JW lj caused by the plasma described above may not be applied to the semiconductor wafer, and the ashing speed is slow at 50 to 150 nm/mi, which takes a long time to process. There is a problem in that single wafer processing, which is suitable for processing semiconductor wafers one by one, cannot be performed.

The present invention has been made in response to such conventional circumstances,
The object of the present invention is to provide an ashing device that can perform a fast ashing process for a photoresist film without damaging the semiconductor wafer, and can handle processing such as confection processing of large-diameter semiconductor wafers.

[Structure 1 of the Invention (Means for Solving the Problems) In other words, the present invention provides an ashing apparatus for removing a film deposited on the surface of a semiconductor wafer by oxidizing it with a gas containing ozone. a gas outflow section that causes the gas to flow out toward the semiconductor wafer from a substantially planar opposing section that closely opposes the wafer; a cooling mechanism disposed in the opposing section that cools the opposing section; and a cooling mechanism that heats the semiconductor wafer. It is characterized by not having a heating device.

(Function) The ashing apparatus of the present invention is provided with a gas outflow section that allows ozone-containing gas to flow out toward the semiconductor wafer from the substantially planar facing section that closely opposes the semiconductor wafer. By preventing oxygen gas containing ozone from flowing out from this gas outlet, new ozone can be supplied to the semiconductor wafer surface, promoting the oxidation chemical reaction between oxygen atomic radicals and the film deposited on the semiconductor wafer. You can avoid it.

In addition, a cooling UJ groove for cooling the opposing portion is arranged in the planar opposing portion of the gas outlet, and the opposing portion is kept at a low temperature with respect to the semiconductor wafer heated by the heating device. Suppresses ozone decomposition. Then, the debris flowing out from this opposing part is heated and decomposed by the heated semiconductor wafer and the surrounding atmosphere, generating a large amount of oxygen atomic radicals, which makes it possible to achieve a high and uniform ashing rate. can.

(Example) Hereinafter, an example of the ashing device of the present invention will be described with reference to the drawings.

FIG. 1 shows an ashing apparatus according to an embodiment of the present invention. In the ashing apparatus of this embodiment, a mounting table 13 for holding a semiconductor wafer 12 by suction using a vacuum chuck or the like is arranged in a processing chamber 11. This mounting table 1
3 is a heater 15 controlled by the temperature control device 14;
It has a built-in structure and is configured to be movable up and down by a lifting device 16.

Above the mounting table 13, as shown in FIG.
Diffusion plate 1 forming a substantially planar facing portion close to and facing the
7c is disposed. A pipe 18a connected to the cooling device 18 and through which cooling water or the like is circulated from the cooling device 18 is disposed within the diffusion plate 17C.

The gas outlet 17 is connected to an ozone generator 21 which is connected to an oxygen supply source 20 via one gas flow regulator. Note that an exhaust port 22 is provided at the lower part of the processing chamber 11, and exhaust is performed from this exhaust port 22 by an exhaust device 23.

The ashing device of this embodiment having the above configuration performs ashing as follows.

That is, first, the mounting table 13 is lowered by the lifting device 16, and a gap is provided between it and the gas outlet section 17 in which an arm or the like of a wafer transport device (not shown) is introduced, and the semiconductor wafer 12 is moved to the wafer 1f transport device, etc. is placed on the mounting table 13 and held by suction.

After that, the mounting table 13 is raised by the lifting device 16,
The distance between the diffusion plate 17G of the gas outlet portion 17 and the surface between the semiconductor wafers 12 is set to a predetermined distance of, for example, about 0.5 to 20 mm. In this case, the gas outlet portion 17 may be moved up and down by a lifting device.

Next, the heater 15 built into the mounting table 13 is controlled by the temperature control device 14, and the semiconductor wafer 12 is heated at an angle of, for example, 150°.
It is heated to a temperature in the range of about C to 500"C, and cooling water or the like is circulated from the cooling device 18 into the pipe 18a arranged in the diffuser plate 17c to maintain the temperature of the diffuser plate 17C at about 25 degrees C or less, for example. .

Then, the oxygen gas containing ozone supplied from the oxygen supply source 20 and the ozone generator 21 is transferred to the waste flow rate controller 1.
Adjust the flow rate to, for example, about 3 to 15 iQ/min depending on the number of small holes 17b of the enlarged rli temporary 17c.
from the exhaust device 23 toward the semiconductor wafer 12.
For example, the gas pressure in the processing chamber 11 is 700 to 200.
I think it should be within the Torr range.

At this time, as shown by arrows in FIG. 3, the gas flowing out from the many small holes 17b of the gas outflow section 17 flows from the center of the semiconductor wafer 12 to the periphery between the diffusion plate 17G and the semiconductor wafer 12. Forming a gas flow.

Here, ozone flows out from inside the cooled diffusion plate 17C, is heated by the heated semiconductor wafer 12J3 and the surrounding atmosphere, and is decomposed to generate many acids and elementary atomic radicals. And this M7? The atomic radicals react with the photoresist film deposited on the surface of the semiconductor wafer 12, ashing is performed, and the photoresist film is removed.

The reason why the temperatures of the semiconductor wafer 12 and the diffusion plate 17G are set as explained above is as follows. In other words, the lifespan of ozone generated by the ozone generator 21 is
As shown in the graph of FIG. 4, where the vertical axis is the ozone decomposition half-life and the horizontal axis is the temperature of the ozone-containing gas, the lifetime of ozone rapidly shortens as the temperature increases.

For this reason, it is preferable that the temperature fM of the opening of the gas outlet portion 17 is about 25°C or less, while the temperature of the semiconductor wafer 12 is preferably heated to about 150'C or more.

In the graph of FIG. 5, the vertical axis represents the ashing speed, and the horizontal axis represents the flow rate of the ozone-containing gas.
Ashing UI'M when a 6-inch semiconductor wafer 12 is heated to 300°C using the distance between 2 as a parameter
It shows the change in

Note that the ozone concentration is adjusted to be approximately 3 to 10% by weight. As can be seen from this graph, in the ashing apparatus of this embodiment, the semiconductor wafer 12 and the gas outlet 1
By setting the flow rate of the ozone-containing gas in the range of about 2 to 403λ (Sβ is the flow rate converted to room temperature and normal pressure), the ashing speed can be increased from 1 to several μm.
/min high-speed ashing processing can be performed.

In this embodiment, the gas outlet portion 17 is formed by disposing a diffusion plate 17c having a large number of small holes 17b at the opening of a cone-shaped cone portion 17a, and a cooling pipe 18a is provided within this diffusion plate 17C. However, the present invention is not limited to such embodiments; for example, the diffuser plate 17c may be
J shown in the figure: a diffusion plate 27c with a plurality of concentric slits 27b, a diffusion plate 37G made of a sintered body of metal or relamic as shown in FIG. 7, a linear shape as shown in FIG. Diffusion plate 47G equipped with slits 47b
, a diffuser plate 57C having regularly arranged small holes 57b of different sizes as shown in FIG. 9, a diffuser plate 67c having spiral slits 67b as shown in FIG. 10, or the like.

In addition, as shown in FIGS. 11 and 12, when gas is caused to flow out from a plurality of areas divided by concentric slits 77b, linear slits 87b, etc., or exhaust gas is also exhausted from these slits. The present invention can also be applied to cases in which such methods are carried out. In addition, the cooling mechanism may include a cooling mechanism based on an electronic cooling element using a Peltier element or the like, focusing on the circulation of cooling water, etc.1. These cooling pipes 18a and electronic cooling cords 18b are connected to electronic cooling elements 18, as shown in FIGS. 13 to 16, for example.
Of course, it is possible to arrange the cooling pipe 18a in any other way, such as by arranging the cooling pipe 18a on the front or back surface of the slit component 97, and by providing the cooling pipe 18a in two layers.

Furthermore, in this example, the case of a photoresist film as an ashing target was explained, but it can be applied to various things such as ink removal and solvent removal. The ozone-containing gas is not limited to oxygen; any gas that does not react with ozone, particularly an inert gas such as N2, Ar, Ne, etc., may be used by containing ozone.

[Effects of the Invention] As described above, the ashing device of the present invention does not cause lt4 damage to semiconductor wafers and the ashing speed is uniform and high, so even large diameter semiconductor wafers can be processed in one wafer.
This allows ashing to be done in a short time.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a seven-tushing device according to an embodiment of the present invention, FIG. 2 is a bottom view showing the main parts of FIG. 1, and FIG. 3 is an explanatory diagram showing the flow of gas containing ozone. Figure 4 is a graph showing the relationship between the half-life of ozone and temperature, Figure 5 is a graph showing the relationship between ashing rate and the distance between the ozone-containing gas Takigawa and the gas outlet and the semiconductor uenotsuji. Figure 12 is a bottom view showing a modified example of the gas outlet, and Figures 13~
Figure 16 shows a modification of the cooling mechanism installed at the gas outlet.
, a side sectional view, and FIG. 17 are configuration diagrams showing a conventional ashing device. 12... Semiconductor wafer, 17... Noj
Gas outflow part, 17C...Diffusion plate, 18...
・Cooling device, 18a... Cooling piping, 21...
...Ozone generator. Applicant Tokyo Electron Co., Ltd. Agent Patent Attorney Satoshi Suyama - Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 S7 Garden Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Fig. 13 Fig. 14 Fig. 15) aa Fig. 16 Fig. 17

Claims (1)

[Claims] (1) In an ashing device that oxidizes and removes a film deposited on the surface of a semiconductor wafer with an ozone-containing gas, the gas is directed to the semiconductor wafer from a substantially planar facing portion that closely opposes the semiconductor wafer. What is claimed is: 1. An ashing device comprising: a gas outflow section for causing a gas to flow out toward the opposing section; a cooling mechanism that is disposed in the opposing section and that cools the opposing section; and a heating device that heats the semiconductor wafer.