JPH06101424B2 - Semiconductor wafer processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention performs an ashing process for oxidizing and removing a photoresist film or the like deposited on a semiconductor wafer using ozone. The present invention relates to a semiconductor wafer processing apparatus.

(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.

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 an example of 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.

As a semiconductor wafer processing apparatus for performing the ashing process for removing the photoresist film, a device using oxygen plasma is generally used.

A semiconductor wafer processing apparatus that performs an ashing process on a photoresist film with oxygen plasma places a semiconductor wafer with a photoresist film in a processing chamber, converts oxygen gas introduced into the processing chamber into a plasma by a high-frequency electric field, and generates oxygen. The photoresist film, which is an organic substance, is oxidized by atomic radicals and decomposed into carbon dioxide, carbon monoxide, and water for removal.

Further, there is a semiconductor wafer processing apparatus that generates oxygen atom radicals by irradiating ultraviolet rays and performs ashing processing in batch processing.

FIG. 11 shows a semiconductor wafer processing apparatus for generating oxygen atom radicals by such ultraviolet irradiation. A large number of semiconductor wafers 2 are vertically arranged at a predetermined interval in the processing chamber 1. Ultraviolet rays from an ultraviolet arc tube 3 installed at the upper part of the chamber are irradiated through a transparent window 4 such as quartz provided on the upper surface of the processing chamber 1 to excite oxygen filled in the processing chamber 1 to generate ozone. Let The oxygen atom radicals generated from this ozone atmosphere are transferred to the semiconductor wafer 2
To effect ashing processing.

(Problems to be Solved by the Invention) However, among the conventional semiconductor wafer processing apparatuses described above, in the semiconductor wafer processing apparatus using oxygen plasma, in the semiconductor wafer processing apparatus, ions and electrons accelerated by an electric field existing in the plasma are transferred to the semiconductor wafer. However, there is a problem in that the semiconductor wafer is damaged due to the irradiation.

Further, in a semiconductor wafer processing apparatus using ultraviolet rays, the semiconductor wafer is not damaged by the above-mentioned plasma, but the ashing speed is slow at 50 to 150 nm / min, and it takes time to process the semiconductor wafer. There is a problem that the single-wafer processing, which is suitable for the above processing, for processing the semiconductor wafers one by one cannot be performed.

The present invention has been made in response to such conventional circumstances,
An object of the present invention is to provide a semiconductor wafer processing apparatus which does not damage the semiconductor wafer, has a high processing speed, and can be used for single-wafer processing of large-diameter semiconductor wafers.

[Structure of the Invention] (Means for Solving the Problems) That is, the first aspect of the present invention is to provide a mounting table provided in a processing chamber for mounting a semiconductor wafer, and a temperature of the semiconductor wafer built in the mounting table. A temperature control device that controls the temperature of the semiconductor wafer, a gas outflow portion that is arranged to face the semiconductor wafer and has an opening for flowing gas toward the semiconductor wafer, and a gas outlet that faces the semiconductor wafer, and discharges exhaust gas from the processing chamber. A gas discharge part having an opening is provided, and the opening of the gas outflow part and the opening of the gas discharge part are alternately provided.

The second aspect of the present invention is to provide a mounting table, which is provided in a processing chamber, and on which a semiconductor wafer is mounted, an opening which is arranged to face the semiconductor wafer and which allows gas to flow toward the semiconductor wafer, and the exhaust gas to be treated. A gas outflow / exhaust portion provided with openings for exhausting from inside the chamber, and a relative position of the mounting table and the gas outflow / exhaust portion are set to an interval at which an arm of a transfer device for transferring the semiconductor wafer is introduced. An elevating device for changing between the processing intervals of the semiconductor wafer, the elevating device elevating and lowering at least one of the mounting table and the gas outflow / exhaust part.

(Operation) In the semiconductor wafer processing apparatus of the present invention, the semiconductor wafer processing apparatus is provided with an opening facing the semiconductor wafer, through which gas flows toward the semiconductor wafer, and an opening through which exhaust gas is discharged from the processing chamber.

By flowing out oxygen gas containing ozone, etc., from these openings, new ozone can be supplied to the surface of the semiconductor wafer, and the oxidation chemical reaction between the oxygen atom radicals and the film deposited on the semiconductor wafer is promoted. be able to.

Further, the exhaust gas generated by the oxidation chemical reaction with the deposited film on the surface of the semiconductor wafer is immediately discharged to the outside of the treatment room.

Therefore, since the exhaust gas is immediately removed from the surface of the semiconductor wafer without passing through the surface of the semiconductor wafer, for example, the ashing speed on the vertical axis and the distance from the center of the semiconductor wafer on the horizontal axis are indicated by the dotted line in the graph of FIG. As shown by a, there is no difference in the ashing speed depending on the part of the semiconductor wafer in the central part and the peripheral part and the like, and a high speed and uniform ashing speed can be obtained over the entire semiconductor wafer as shown by the solid line b.

By cooling the gas outlet and the gas outlet, it is possible to supply a gas having a preferable gas temperature to the semiconductor wafer.

Further, by forming the openings of the gas outlet and the gas outlet in parallel elongated slits, uniform processing can be performed over the entire semiconductor wafer.

Further, in the semiconductor wafer processing apparatus of the second invention, the relative position between the mounting table and the gas outflow / exhaust section is set to a wide interval in which the arm of the transfer apparatus for transferring the semiconductor wafer is introduced and a narrow position for processing the semiconductor wafer. By changing the distance and the distance, the optimum arrangement for processing the semiconductor wafer can be obtained.

(Embodiment) An embodiment of the semiconductor wafer processing apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 shows a semiconductor wafer processing apparatus according to an embodiment of the present invention. In the semiconductor wafer processing apparatus according to this embodiment, a processing chamber 11 is mounted with a semiconductor wafer 12 sucked and held by, for example, a vacuum chuck. A table 13 is arranged, and the table 13 includes a heater 15 controlled by a temperature controller 14.
Is built in, and is configured to be movable up and down by a lifting device 16.

Above the mounting table 13, as shown in FIG.
A gas outflow / exhaust part 17 having 10 narrow slit-shaped openings 17a ... 17j parallel to each other having a width of about 1 mm, preferably about 1 to 2 mm is arranged. Is cooled by cooling water or the like circulated from the cooling device 18.

Further, the openings 17a to 17e of the gas outflow / exhaust portion 17 are connected to the oxygen supply source 20 via the gas flow rate controller 19 and are an ozone generator.
21 and the openings 17f to 17j are connected to the discharging device 22.

Then, in the semiconductor wafer processing apparatus of this embodiment having the above configuration, ashing is performed as follows.

That is, first, the mounting table 13 is lowered by the elevating device 16, and an interval, such as an arm of a wafer transfer device (not shown), is introduced between the mounting table 13 and the gas outflow portion 17, and the semiconductor wafer 12 is provided.
Is mounted on the mounting table 13 by this wafer transfer device,
Adsorbed and held.

After that, the mounting table 13 is raised by the elevating device 16, and the gap between the gas outflow / exhaust portion 17 and the surface of the semiconductor wafer 12 is set to a predetermined gap of, for example, about 0.5 to 20 mm. In this case, the gas outflow / exhaust unit 17 may be moved up and down by the lifting device.

Then, the heater 15 built in the mounting table 13 is installed in the temperature control device.
Controlled by 14, the semiconductor wafer 12 is heated to, for example, a range of about 150 ° C. to 500 ° C., and the oxygen supply source 20 and the ozone generator 21 are heated.
Oxygen gas containing ozone supplied from the device is adjusted by the gas flow rate controller 19 to have a flow rate of, for example, about 3 to 15 / min, and is made to flow out from the openings 17a to 17e toward the semiconductor wafer 12, and the discharge device 22 is provided. Thus, the gas is exhausted from the openings 17f to 17j so that the gas pressure in the processing chamber 11 is in the range of about 700 to 200 Torr.

At this time, as shown by the arrow in FIG. 3, between the gas outflow / exhaust portion 17 and the semiconductor wafer 12 is directed from the openings 17a to 17e to the semiconductor wafer 12 and reflected on the surface of the semiconductor wafer 12, and the opening 17f. Heading to ~ 17j, a stream of gas exiting here is formed. Therefore, the exhaust gas generated by the oxidation chemical reaction with the deposited film on the surface of the semiconductor wafer is immediately removed from the surface of the semiconductor wafer 12 without passing through the surface of the semiconductor wafer 12, so that Fresh ozone can be constantly supplied to the surface, and the oxidative chemical reaction between the oxygen atom radicals and the film deposited on the semiconductor wafer 12 can be promoted.

Then, for example, the semiconductor wafer in the central portion and the peripheral portion
It is possible to obtain a high speed and uniform ashing speed over the entire semiconductor wafer 12 without causing a difference in ashing speed depending on the 12 parts.

The life of the ozone generated by the ozone generator 21 depends on the temperature. As shown in the graph of FIG. 4, the vertical axis represents the ozone decomposition half-life and the horizontal axis represents the temperature of the gas containing ozone. When the temperature rises, the life of ozone shortens sharply.
Therefore, it is preferable that the temperature of the opening of the gas outflow portion 17 is about 25 ° C. or lower, while the temperature of the semiconductor wafer 12 is 150 ° C. or lower.
It is preferable to heat to about C or higher.

In the graph of FIG. 5, the vertical axis represents the ashing speed, the horizontal axis represents the flow rate of the gas containing ozone, and the distance between the gas outflow / exhaust portion 17 and the semiconductor wafer 12 in the semiconductor wafer processing apparatus of this embodiment described above. Shows the change in the ashing speed when the 6-inch semiconductor wafer 12 is heated to 300 ° C. The ozone concentration is 3-10% by weight.
Adjusted to a degree. As can be seen from this graph, in the semiconductor wafer processing apparatus of this embodiment, the distance between the semiconductor wafer 12 and the gas outflow / exhaust portion 17 is several mm, and the flow rate of the gas containing ozone is 2 to 40 S (S is normal temperature at normal temperature). By setting the flow rate within a range of about (pressure conversion), it is possible to perform high-speed ashing processing with an ashing speed of 1 to several μm / min.

In this embodiment, the gas outflow / exhaust portion 17 is composed of parallel slit-shaped openings 17a ... 17j, but the present invention is not limited to this embodiment. For example, as shown in FIG. 27j may be formed by a plurality of concentric slits 27a ... 27j, or even without slits, for example, as shown in FIG. 7, an opening 37a in which a diffusion plate made of a sintered body such as metal or ceramic is arranged. Needless to say, it may be constituted by 37j or by openings 47a ... 47j in which a diffusion plate having small holes is arranged as shown in FIG.

Further, as shown in FIG. 9, the openings 17a to 17e are also connected to the discharge device 22, and the openings 17f to 17j are also connected to the gas flow rate controller 19, and the valves 23a for switching the gas flow paths are connected to these pipes. ~ 23d are arranged so that openings 17a to 17e through which gas flows out and openings through which exhaust gas is discharged in one ashing process step
It is also possible to switch 17f to 17j depending on time or the like so as to perform outflow and discharge of gas.

Further, in this embodiment, the case of the photoresist film is explained as the ashing target, but it is applicable to various things such as ink removal and solvent removal, and what kind of ashing target is applicable if it can be oxidized and removed. The ozone-containing gas is not limited to oxygen, and a gas that does not react with ozone, particularly an inert gas such as N ₂ , Ar, or Ne, can be used by incorporating ozone.

[Effects of the Invention] As described above, in the semiconductor wafer processing apparatus of the present invention, since the semiconductor wafer is not damaged and the processing speed is uniform and high, even a large-diameter semiconductor wafer or the like can be processed in a short time by single-wafer processing. Can be processed with.

[Brief description of drawings]

FIG. 1 is a block diagram showing a semiconductor wafer processing apparatus according to an embodiment of the present invention, FIG. 2 is a bottom view showing a main part of FIG. 1, FIG. 3 is an explanatory view showing a gas flow, and FIG. Is a graph showing the relationship between the ozone half-life and temperature, FIG. 5 is a graph showing the relationship between the ashing rate and the gas flow rate, and the distance between the gas outflow part and the semiconductor wafer, and FIGS. 6 to 8 are the gas outflow and exhaust. FIG. 9 is a bottom view showing a modified example of the part, FIG. 9 is a configuration diagram showing a modified example of the semiconductor wafer processing apparatus shown in FIG. 1, and FIG. 10 is a graph showing the relationship between the ashing speed and the distance from the center of the semiconductor wafer. FIG. 11 is a block diagram showing a conventional semiconductor wafer processing apparatus. 12 ... Semiconductor wafer, 17 ... Gas outflow / exhaust section, 17a-1
7j ... Opening, 19 ... Gas flow controller, 21 ... Ozone generator, 22 ... Exhaust device.

Claims (4)

[Claims] 1. A mounting table provided in a processing chamber for mounting a semiconductor wafer, a temperature control device built in the mounting table for controlling the temperature of the semiconductor wafer, and arranged to face the semiconductor wafer. A gas outflow part having an opening for outflowing gas toward the wafer; and a gas exhaust part having an opening for facing the semiconductor wafer and exhausting exhaust gas from the processing chamber, wherein the gas outflow part has an opening. A semiconductor wafer processing apparatus, wherein the openings of the gas discharge portion are provided alternately. 2. The semiconductor wafer processing apparatus according to claim 1, further comprising a cooling device for cooling the gas outflow portion and the gas exhaust portion. 3. The semiconductor wafer processing apparatus according to claim 1, wherein the opening of the gas outlet and the opening of the gas outlet are parallel elongated slit-shaped openings. 4. A mounting table provided in a processing chamber for mounting a semiconductor wafer, an opening arranged to face the semiconductor wafer, for discharging gas toward the semiconductor wafer, and exhaust gas discharged from the processing chamber. The gas outflow / exhaust portions with the openings alternately provided, the relative positions of the mounting table and the gas outflow / exhaust portion, the interval at which the arm of the transfer device for transferring the semiconductor wafer is introduced, and the semiconductor wafer A semiconductor wafer processing apparatus, comprising: an elevating device that changes between a processing interval and an elevating device that elevates and lowers at least one of the mounting table and the gas outflow / exhaust portion.