JPS63186430A - Ashing process - Google Patents

Abstract

PURPOSE:To enable large diameter semiconductor wafers to cope with the single sheet processing etc. by accelerating the ashing speed of photoresist film by a method wherein the ashing gas being heated is fed to the surface of substrate to be processed. CONSTITUTION:Ashing gas containing ozone produced by an ozone producer 16 provided with an oxygen supply source 15 is heated by a heating mechanism 14 to be fed to the surface of a semiconductor wafer 9 mounted on a base 10 from an outlet provided on a flat plate 6. At this time, the base 10 is previously heated by a heater 11 built-in the base 10 to be controlled by a temperature controlling mechanism 12 resultantly heating the semiconductor wafer 9 mounted on the base 10. The ashing gas heated in such a state is fed to the surface of semiconductor wafer 9. Through these procedures, the heating mechanism 14 can be previously heated not to cool down the semiconductor wafer 9. Thus, the ashing unevenness due to temperature fluctuation can be avoided.

Description

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

(Prior Art) Generally, fine patterns forming semiconductor integrated circuits are formed by using, for example, an organic polymer photoresist film formed by exposure and development as a mask, and etching the base film of this 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.

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.

There is an ashing device that performs batch ashing processing by generating oxygen atom radicals by irradiating ultraviolet rays.

FIG. 2 shows an ashing device that generates oxygen atomic radicals through ultraviolet irradiation. Ultraviolet rays from an ultraviolet light emitting tube 3 installed in the chamber 1 are irradiated through a transparent window 4 made of quartz or the like provided on the upper surface of the processing chamber 1, and the oxygen filled in the processing chamber 1 is excited to generate ozone.

Oxygen radicals generated from this ozone atmosphere are then applied to the semiconductor wafer 2 to perform an ashing process.

(Problems to be Solved by the Invention) However, in the conventional ashing device using ultraviolet rays described above, the ashing speed is 50 to 150 nm/mi.
Since the processing time is slow, for example, there is a problem that single-wafer processing, in which semiconductor wafers are processed one by one, which is suitable for processing large-diameter semiconductor wafers, cannot be performed. The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide an ashing method that has a high ashing speed for a photoresist film and can be applied to single-wafer processing of large-diameter semiconductor wafers.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method for performing ashing by flowing ashing gas onto the surface of the substrate to be processed through an opening provided in an outflow plate that is disposed facing the substrate at a predetermined distance from the substrate to be processed. , the ashing gas is heated and flows out onto the surface of the substrate to be processed.

(Function) When ashing gas flows out onto the surface of the substrate to be processed through the opening provided in the outflow plate, which is disposed facing the substrate at a predetermined distance from the substrate to be processed, the ashing gas is heated in advance by a heating means. death.

By flowing out onto the surface of the substrate to be processed, it is possible to prevent the temperature of the substrate to be processed and the outflow plate from decreasing due to contact when the ashing gas flows from the center to the periphery of the substrate to be processed.

(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.

In FIG. 1, a cylindrical upper chamber 5 with a U-shaped cross section is provided, which is movable up and down by a lifting mechanism (not shown). A flat plate 6 made of glass, for example, is provided in the upper chamber 5 to allow the ashing gas to flow out uniformly. An outflow lower having a diameter of, for example, 8 mm is provided on the central axis of the flat plate 6 to allow the ashing gas to flow out.

A lower chamber 8 is provided to engage with the upper chamber 5, and a disk-shaped mounting table 10 on which a substrate to be processed, such as a semiconductor wafer 9, can be placed is provided within the lower chamber 8. . A heater 11 is installed inside the mounting table 10. The temperature of this heater 11 can be freely controlled by a temperature control mechanism 12 provided outside the lower chamber 8.
As a result, the mounting table 10 is configured to be temperature controllable. An ozone generator 16 equipped with an oxygen supply source 15 is provided through a gas flow conduit 13 via a heating mechanism 14, for example, a ceramic heater, so that the cutting gas flows onto the surface of the semiconductor wafer 9 set on the mounting table 10. has been done. Further, an exhaust mechanism 19 for exhausting the inside of the processing chamber 18 is provided at the bottom of the lower chamber 8 via an exhaust pipe 20. The ashing device is configured in this way. Next, a method of ashing a semiconductor wafer using the above-described ashing apparatus will be described.

The upper chamber 5 is raised by an elevating mechanism (not shown), and the semiconductor wafer 9 is sucked by a transport mechanism such as a hand arm (not shown) to a predetermined position on the mounting table 10 provided in the lower chamber 8. Place it in the correct position. The upper chamber 5 is lowered by a lifting mechanism and connected to the lower chamber 8 in an airtight manner.

Next, ashing gas containing ozone generated by an ozone generator 16 equipped with an oxygen supply source 15 is heated to a heating mechanism 14.
For example, it is heated to 150 to 500° C., for example, 350° C., by a ceramic heater, and flows out from an outflow lower provided on the flat plate 6 onto the surface of the semiconductor wafer 9 set on the mounting table 10. At this time, the temperature control mechanism 12 controls the temperature control mechanism 12 of the mounting table 10 so that the heater 11 installed inside the mounting table 10 has a temperature of 300, for example.
Since it is heated to about .degree. C., the set semiconductor wafer 9 is also heated. In this state, the heated ashing gas flows out onto the surface of the semiconductor wafer 9. By heating the ashing gas with the heating mechanism 14, the semiconductor wafer X9 is heated by the ashing gas when the ashing gas flows out.
to prevent cooling.

Then, the photoresist film deposited on the heated surface of the semiconductor wafer 9 reacts with the ashing gas.

Ashing is performed to remove the photoresist film.

Thereafter, the ashing gas in the processing chamber 18 is decomposed by an ozone decomposer (not shown) and exhausted from the exhaust mechanism 19 via the exhaust pipe 20. Then, the upper chamber 5 is raised by the lifting mechanism, and the semiconductor wafer 9 is transported to the next process by the transport mechanism.

In the above embodiment, a ceramic heater was used as the heating mechanism, but the heating mechanism is not limited to the above as long as it can heat the ashing gas.

As described above, according to this embodiment, by heating the ashing gas in advance, the semiconductor wafer is not cooled down, so that uneven ashing due to temperature changes can be prevented.

〔Effect of the invention〕

As explained above, according to the present invention, by heating the ashing gas in advance, the substrate to be processed is not cooled down, so that uniform ashing processing can be performed without uneven ashing, and large-diameter substrates can be processed. Suitable for substrate processing,
It becomes possible to perform single-wafer processing in which each substrate to be processed is processed one by one.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an ashing device in the ashing method of the present invention, and FIG. 2 is a block diagram of a conventional ashing device. 2.9... Semiconductor wafer, 14... Heating mechanism, 18... Processing chamber. Patent applicant Tokyo Electron Ltd. Figure 1 Figure 2

Claims (3)

[Claims] (1) In a method of ashing by flowing ashing gas onto the surface of the substrate to be processed through an opening provided in an outflow plate disposed opposite to the substrate at a predetermined distance, the preheated ashing gas is applied to the surface of the substrate to be processed. An ashing method characterized by spilling onto the substrate surface. (2) The above ashing gas heating temperature is 150-500℃
An ashing method according to claim 1. (3) The ashing method according to claim 1, wherein the heating means is a ceramic heater.