JPH0810689B2 - Ashing processing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ashing processing apparatus for removing a film deposited on a substrate to be processed.

(Prior Art) Generally, a fine pattern of a semiconductor integrated circuit is formed by etching a base film formed on a semiconductor wafer using a photoresist film of an organic polymer formed by exposure and development as a mask. Be done. Therefore, the photoresist film used as the mask needs to be removed from the surface of the semiconductor wafer after the etching process. Etching or ashing is performed as a process for removing the photoresist film in such a case. In particular, etching and ashing processing using plasma are the mainstream.

However, the integration density of semiconductors has improved, and from 256 Mbit to 1 M
As the bit and 2M bits are improved, the wiring and the like have narrow intervals, and a strong discharge is generated in the plasma atmosphere, the semiconductor wafer is damaged, and the yield is significantly reduced.
The applicant has developed an asher that does not suffer this damage. The ashing process is used for removing resist, cleaning silicon wafer and mask, removing ink, removing solvent residue, etc., and is suitable for performing dry cleaning process in a semiconductor process.

Further, there is an ashing device that generates an oxygen atom radical by irradiating with ultraviolet rays and performs the ashing process in a batch process.

FIG. 3 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 atom radicals generated from the ozone atmosphere are caused to act on the semiconductor wafer 2 to perform the ashing process.

(Problems to be Solved by the Invention) However, the conventional ashing apparatus using ultraviolet rays has a problem that ashing unevenness is likely to occur and single-wafer processing suitable for processing a large-diameter semiconductor wafer cannot be performed.

The present invention has been made in view of the above points, and an object of the present invention is to provide an ashing processing apparatus that can perform uniform ashing processing without unevenness in processing when processing a substrate such as a semiconductor wafer.

(Means for Solving the Problems) In order to achieve the above object, an ashing processing apparatus according to the present invention is provided with a mounting table provided in a processing chamber, and an ashing apparatus that opposes a substrate to be processed mounted on the mounting table. An ashing processing device having a gas outflow portion, configured to flow out ashing gas from the outflow portion to perform ashing processing on the substrate to be processed, wherein the outflow portion is a glass flat plate. Slit grooves are provided on the surface of the flat plate facing the substrate to be processed so as to be parallel to each other, exhaust holes are formed in each slit groove, and ashing gas is applied to the substrate to be processed. A plurality of first openings and second openings to flow out are alternately provided on the flat plate between the slit grooves along the longitudinal direction of the slit grooves, and the first openings and the second openings are further provided. Are characterized in that the ashing gas is allowed to flow out alternately.

(Operation) According to the ashing treatment apparatus of the present invention, first, the first opening and the second opening for letting out the ashing gas are provided in the flat plate made of glass, but the glass has low thermal conductivity. Therefore, the flat plate facing the substrate to be processed has an excellent property of blocking the temperature atmosphere from the space above the substrate to be processed and the ceiling wall of the processing chamber. Therefore, the temperature atmosphere suitable for the treatment can be stably maintained.

Further, since the first opening and the second opening are arranged along the longitudinal direction of the slit groove between the slit grooves having the exhaust holes, the groups and rows of the openings formed by these openings are arranged. Gas interference due to outflow of ashing gas is prevented. And the group,
As for each opening in the row, since the ashing gas flows out alternately from the first opening and the second opening,
Gas interference due to outflow of ashing gas between the first opening and the second opening is prevented.

Therefore, uniform ashing processing without ashing unevenness is possible.

(Example) Hereinafter, an example in which the method of the present invention is applied to an assink 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 a flat plate 7 made of glass for allowing the ashing gas to uniformly flow out. The flat plate 7 is provided with openings, for example, a plurality of openings 6a and 6b having a diameter of about 0.5 to 2.0 mm alternately as shown in FIG. .

The flat plate 7 has a surface larger than the substrate to be processed, for example, the semiconductor wafer 16, and has a stepped shape at the periphery. For example, a Teflon gas flow conduit 8a is connected to each of the openings 6a. The pipe 8a is connected to an ozone generator 12 having an oxygen supply source 11 via a switching valve 9a and a gas flow rate controller 10.

On the other hand, for example, a gas flow conduit made of Teflon is provided in each of the openings 6b.
8b is connected. The pipe 8b is connected to the ozone generator 12 having the oxygen supply source 11 via the gas flow rate controller 10 via the switching valve 9b. That is, the switching valves 9a and 9b
This enables intermittent control of the ashing gas.
A slit groove 18 is provided at an interval that forms a pair of two opening rows formed by the openings 6a and 6b, and an exhaust hole 19 is formed at the center of the slit 18.

A lower chamber 13 is provided so as to engage with the upper chamber 5. In the lower chamber 13, there is provided a circular hill-shaped mounting table 15 for mounting the semiconductor wafer 16 on the flat plate.
17 are provided at equal intervals over the peripheral portion of the central portion. A heater 21 for setting the semiconductor wafer 16 to a desired temperature is provided in the mounting table 15 to form a reaction container 22.

The temperature of the heater 21 is adjusted by a temperature control mechanism 14 provided outside the container 22. By disposing a temperature sensor (not shown) near the semiconductor wafer 16, a constant temperature can be automatically set. An exhaust hole 23 is provided at the center of the bottom surface of the reaction container 22 and is exhausted by an exhaust mechanism 17. It is also beneficial that exhaust gas decomposes ozone by a catalyst or the like and then discharges it.

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

The upper chamber 5 is raised by the lifting mechanism,
A substrate (eg, semiconductor wafer 16) to be processed is automatically transported and placed at a predetermined position on the mounting table 15 provided in the lower chamber 13 by a transport mechanism (not shown) such as a hand arm.

The semiconductor wafer 16 can be manufactured with reproducible elements having the same characteristics by performing orientation / fla adjustment as needed.

Next, the upper chamber 5 descends and is connected to the lower chamber 13 to set the inside of the processing chamber in a sealed state. At this time, the flat plate 7 formed of, for example, glass is provided at a position spaced from the surface of the semiconductor wafer 16 by, for example, about 0.5 to 20 mm. In this case, the lower chamber 13 may be moved up and down by an elevating mechanism.

Then, the heater installed in the mounting table 15 is controlled by the temperature controller 14 to heat the semiconductor wafer 16 to a range of, for example, about 150 to 500 ° C., and the ozone generator provided with the oxygen supply source 11 is provided.
The ashing gas generated by 12 is adjusted by the gas flow rate controller 10 so that the flow rate is, for example, about 3 to 15 / min. A plurality of openings provided on the flat plate 7 being installed
It flows out onto the semiconductor wafer 16 on the mounting table 15 from 6a and 6b.

At this time, when the adjacent openings 6a and 6b simultaneously flow out the ashing gas, the ashing gas flowing out from the opening 6a and the ashing gas flowing out from the opening 6b interfere with each other,
At the intermediate position between the opening 6a and the opening 6b, the flow rate of the asig gas becomes 0 m / sec, and it becomes difficult to remove the ashing of the film deposited on the surface of the semiconductor wafer 16 directly below this intermediate position, so In order to prevent the above interference, the outflow of the ashing gas between the openings 6a and 6b adjacent to each other is switched to alternately flow out. This is the same as the switching valve 9a
9b is always operated in reverse, and when the switching valve 9a is opened, the switching valve 9b is closed at the same time, and the ashing gas is discharged through the switching valve a by the gas flow conduit 8a to the opening 6a.
Flows out from the surface onto the surface of the semiconductor wafer 16 mounted on the mounting table 15.

Further, when the switching valve 9b is opened, the switching valve 9a is closed at the same time, and the ashing gas flows from the opening 6b to the surface of the semiconductor wafer 16 through the switching valve 9b by the gas flow conduit 8b. The switching valves 9a and 9b may be switched every few seconds, or may be switched in half of the ashing gas outflow time.

The interference of the ashing gas between the adjacent openings 6a and 6b is prevented by the method described above. Further, as shown in FIG. 2, the interference of the ashing gas between the lines due to the openings 6a and 6b formed in a line form a slit groove 18 having a width of 0.5 to 5.0 mm and a depth of 1.0 to 5.0 mm, for example, as shown in FIG. By forming an exhaust hole 19 in the slit groove 18 and exhausting gas through an exhaust pipe (not shown), uneven ashing of the semiconductor wafer 16 caused by interference of the ashing gas between the lines is prevented.

The ashing gas is flown from the flat plate 7 to the surface of the semiconductor wafer 16 on the mounting table 15 by the method described above. Then, the ashing gas after the ashing process is decomposed by an ozone decomposer (not shown) and is exhausted from the exhaust mechanism 17.

As described above, the ashing process of the semiconductor wafer 16 is completed, and the semiconductor wafer 16 is transferred to the next step by the transfer mechanism (not shown).

In the above embodiment, the switching valves 9a and 9b always prevent the interference on the semiconductor wafer by the reverse operation, but it is sufficient if the outflow timings of the ashing gas from the openings 6a and 6b are not always synchronized. However, the mechanism is not limited to the above.

As described above, according to this embodiment, since the slit groove 18 having the exhaust hole 19 is provided between the lines formed by the linear openings 6a and 6b, it is caused by the interference of the ashing gas between the lines. The unevenness of ashing of the semiconductor wafer 16 is prevented. Moreover, since the ashing gas alternately flows out from the openings 6a and 6b, the interference of the ashing gas between the adjacent openings 6a and 6b is also prevented. Therefore, uniform ashing processing without ashing unevenness is possible.

Further, since the openings 6a and 6b are provided in the glass flat plate 7 and the flat plate 7 is provided so as to face the semiconductor wafer 16, the heat insulating property from the upper chamber 5 is good,
The processing space has a stable temperature atmosphere, which also improves the uniformity of the ashing process.

(Effect of the invention) According to the present invention, ashing unevenness caused by gas interference at the time of ashing gas outflow is prevented, and
Since the ashing process can be performed in a stable temperature atmosphere, it is possible to perform the ashing process with good uniformity and suitable for a large-diameter substrate to be processed.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an ashing device in an embodiment of the present invention, FIG. 2 is a configuration diagram of a flat plate of an ashing gas outflow portion of FIG. 1, and FIG. 3 is an explanatory diagram showing a configuration of a conventional ashing device. is there. 2,16 ... Semiconductor wafer, 6a, 6b ... Aperture, 7 ... Plate, 8
a, 8b ... Gas flow conduit, 9a, 9b ... Switching valve, 18 ... Slit groove, 19 ... Exhaust hole

Claims (1)

[Claims] 1. A mounting table provided in a processing chamber, and an ashing gas outflow portion facing a substrate to be processed mounted on the mounting table, wherein the ashing gas is caused to flow out from the outflow portion. An ashing processing apparatus configured to perform an ashing process on a substrate to be processed, wherein the outflow portion is composed of a flat plate made of glass, and slit grooves are mutually formed on a surface of the flat plate facing the substrate to be processed. An exhaust hole is provided in each slit groove so as to be parallel to each other, and a plurality of first openings and second openings through which the ashing gas flows out to the substrate to be processed are formed in the slit grooves. The ashing gas is alternately provided on the flat plate in the space along the longitudinal direction of the slit groove, and the ashing gas can alternately flow out from the first opening and the second opening. To, ashing apparatus.