JPH0810690B2 - Ashing method and ashing apparatus - Google Patents

Description

The present invention relates to an ashing method and an ashing apparatus for removing a film deposited on a substrate to be processed.

(Prior Art) Generally, a fine pattern for forming a semiconductor integrated circuit is formed, for example, by using a photoresist film of an organic polymer formed by exposure and development as a mask and etching a base film of this mask. Therefore, the photoresist film used as the mask needs to be removed from the surface of the semiconductor wafer after the etching process.

An ashing process is performed as a process for removing the photoresist film in such a case.

This ashing process is also used for removing resist, cleaning silicon wafers and masks, removing ink, removing solvent residues, etc., and is suitable when performing dry cleaning process in a semiconductor process.

There is an ashing device which generates oxygen atom radicals by irradiating with ultraviolet rays and performs the ashing process in a batch process.

FIG. 2 shows an ashing device for generating oxygen atom radicals by such ultraviolet irradiation.
In this case, a large number of semiconductor wafers 2 are vertically arranged at a predetermined interval, and ultraviolet rays from an ultraviolet ray emitting tube 3 installed in the upper portion of the processing chamber 1 are transparent such as quartz provided on the upper surface of the processing chamber 1. It irradiates through the transparent window 4 to excite the oxygen filled in the processing chamber 1 to generate ozone.

Then, oxygen radicals generated from the ozone atmosphere are caused to act on the semiconductor wafer 2 to perform an ashing process.

(Problems to be Solved by the Invention) However, the above-described conventional ashing device may cause uneven ashing, which is not preferable for processing a large-diameter semiconductor wafer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ashing method and an ashing device that can perform a uniform ashing process while preventing ashing unevenness so as to be applicable to a large-diameter semiconductor wafer.

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention, as an ashing method, removes an ashing gas from an outflow port provided in an outflow plate facing a substrate to be processed at a predetermined distance. In the method of flowing out onto the surface of the substrate to be processed and ashing the substrate to be processed, the outflow plate is made of glass, the substrate to be processed is heated to a predetermined temperature, and the ashing gas is discharged from the outlet. There is provided an ashing method, characterized in that the ashing gas heated to a predetermined temperature is caused to flow out to the substrate to be processed by heating the gas flow conduit leading to the substrate.

Further, the present invention is an ashing device for suitably carrying out the ashing method, wherein an ashing gas is applied to the surface of the substrate to be processed from an outlet provided in an outflow plate facing the substrate to be processed at a predetermined distance. While flowing out, in the device for heating the substrate to be processed to ash the substrate to be processed, the outflow plate is made of glass,
Further, a mounting table on which the substrate to be processed is mounted, a heater with a temperature control mechanism built in the mounting table, a gas flow conduit for guiding the ashing gas to the outlet, and heating for heating the gas flow conduit. And a mechanism,
An ashing device is provided.

(Operation) According to the ashing method of the present invention, the ashing gas is made to flow out to the surface of the substrate to be processed from the outflow port provided on the outflow plate facing the substrate to be processed at a predetermined distance. At this time, the outflow plate is made of glass, the substrate to be processed is further heated to a predetermined temperature, and the gas flow conduit for guiding the ashing gas to the outlet is also heated, so that the ashing gas is also heated to a predetermined temperature. Since this is done, it is possible to perform uniform ashing processing in a stable temperature atmosphere without cooling the substrate to be processed.

Further, according to the ashing device of the present invention, the ashing method can be preferably implemented.

(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 having a U-shaped cross section is provided so as to be vertically movable by an elevating mechanism (not shown). The upper chamber 5 is provided with, for example, a flat plate 6 made of glass for allowing the ashing gas to flow out uniformly. An outlet 7 having a diameter of 8 mm, for example, is provided on the central axis of the flat plate 6 for allowing the ashing gas to flow out. Lower chamber 8 so as to engage with the upper chamber 5
The lower chamber 8 is provided with a disk-shaped mounting table 10 on which a substrate to be processed, for example, a semiconductor wafer 9 can be mounted. A heater 11 is internally provided on the mounting table 10. The temperature of the heater 11 is controllable by a temperature control mechanism 12 provided outside the lower chamber 8, whereby the mounting table 10 is configured to be temperature controllable. A heating mechanism is provided by the gas flow conduit 13 so that the ashing gas flows out to the surface of the semiconductor wafer 9 set on the mounting table 10.
14 An ozone generator 16 provided with an oxygen supply source 15 is provided via, for example, a ceramic heater. 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 by the above-described ashing apparatus will be described.

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

Next, the ashing gas containing ozone generated by the ozone generator 16 provided with the oxygen supply source 15 is heated to 150 to 500 ° C., for example 350 ° C. by the heating mechanism 14 such as a ceramic heater, and the outlet 7 provided on the flat plate 6 is heated. From the surface to the surface of the semiconductor wafer 9 set on the mounting table 10. At this time, since the heater 11 provided in the mounting table 10 has already heated the mounting table 10 to about 300 ° C. by the temperature control mechanism 12, the set semiconductor wafer 9 is also heated. In this state, the heated ashing gas flows out to the surface of the semiconductor wafer 9. The heating mechanism 14 heats the ashing gas to prevent the semiconductor wafer 9 from being cooled by the ashing gas when the ashing gas flows out.

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

After that, the ashing gas in the processing chamber 18 is decomposed by an ozone decomposer (not shown) and is exhausted through the exhaust pipe 20.
Evacuate from 19. Then, the elevating mechanism raises the upper chamber 5, and the transfer mechanism transfers the semiconductor wafer 9 to the next step.

Although the ceramic heater is used as the heating mechanism in the above embodiment, 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, since the semiconductor wafer is not cooled by heating the ashing gas in advance, it is possible to prevent the ashing unevenness due to the temperature change.

〔The invention's effect〕

As described above, according to the present invention, by heating the ashing gas in advance, the substrate to be processed is not cooled, and a uniform ashing process that prevents uneven ashing can be performed in a stable temperature atmosphere, and a large diameter It becomes possible to perform the single-wafer processing suitable for processing the substrate to be processed one by one.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ashing device in an ashing method and an ashing device of the present invention, and FIG. 2 is a configuration diagram of a conventional ashing device. 2,9 ... Semiconductor wafer, 14 ... Heating mechanism, 18 ... Processing room.

Claims (2)

[Claims] 1. A method of ashing a substrate to be processed by causing an ashing gas to flow to the surface of the substrate to be processed from an outlet provided in an outflow plate facing the substrate to be processed at a predetermined distance. The outflow plate is made of glass, and the substrate to be processed is further heated to a predetermined temperature, and by heating a gas flow conduit that guides the ashing gas to the outlet, the ashing gas heated to a predetermined temperature is removed. And flowing out to the substrate to be processed,
Ashing method. 2. An ashing gas is caused to flow to the surface of the substrate to be processed from an outlet provided in an outflow plate facing the substrate to be processed at a predetermined distance, and the substrate to be processed is heated to obtain the ashing gas. In the apparatus for ashing a substrate to be processed, the outflow plate is made of glass, and a mounting table on which the substrate to be processed is mounted, a heater with a temperature control mechanism built in the mounting table, and the ashing gas An ashing device comprising a gas flow conduit leading to the outlet and a heating mechanism for heating the gas flow conduit.