JP2003218090A - Perfect ashing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide that a ashing system can make cleaning and drying cleanly by this system, as well as perfectly removing resists. <P>SOLUTION: It is possible to remove resist perfectly by using ozone gas (concentration exceeding 12%), ozonized water (concentration exceeding 30 PPM), and HF water (0.6%). Also, it is possible to dry clean in this system, protecting from the occurrence of natural oxide, by spraying ultrapure water through the inside of ultrasonic vibrator, and by drying under spin rotation force and reduced pressure of a clean hot N<SB>2</SB>gas (higher than or equal to 120°C) under an atmosphere of clean hot N<SB>2</SB>gas. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001] In a silicon wafer manufacturer, an ashing device is used to remove a resist after ion implantation in a process of manufacturing an epi-wafer. In a device manufacturer, a raw resist is removed and dry etching is performed. An ashing device is used for subsequent resist removal, resist removal after ion implantation, and the like.

[Prior Art] Until now, various dry gases have been used. In order to remove a slight amount of remaining resist, resist peeling or boil sulfate was used to completely remove the resist.

[Problems to be Solved by the Invention] When the resist is completely removed and the conventional ashing device is used, Na contained in the resist becomes mobile ions and becomes hard to yield on the silicon wafer surface. However, in order to prevent this, and to use the LOWK material in the interlayer insulating film, further reduce the damage in the resist removal after the metal wiring.

[Means for Solving the Problems] Conventional ashing apparatuses use dry gas in the form of plasma, micro
The resist was removed by forming a wave shape or a helicon wave shape, but the resist could not be completely removed. At the same time, much dust was attached to the wafer surface. The method invented this time is ozone gas (concentration 12% or more), ozone water (concentration 30PPM or more) and HF water (concentration 0.6%).
Position) was used together to completely remove the resist. And
Using the same apparatus, the wafer surface was cleaned cleanly with ultrapure water with an ultrasonic function, and dried with clean hot N ₂ gas (100 ° C. or higher) and the force of spin rotation to make the wafer surface cleaner.

[Operation] In the perfect ashing apparatus of the present invention, most of the resist is removed using a strong O ₃ gas (concentration: 12% or more). The remaining trace amount of resist is completely removed with ozone water and HF water.
A slight amount of resist is deteriorated and hardened when the resist is removed after the ion implantation. This is also removed by the chemical action of ozone water and HF water.

[Example] In order of Example 1, ozone gas concentration is 12% or more, actually about 20% is used, and ozone gas is wiped on the wafer surface. 20 wafers
Heat gradually to 0-250 ° C. At this time, the pressure in the chamber is 10 Torr. 2. Wipe the surface of the wafer with ozone water from above. (The wafer surface temperature is kept at 80 ° C. or higher.) Concentration of ozone water 3
0PPM or more, at this time, the chamber is processed in clean air of 1 atm. 3. HF water (concentration 0.6%) is wiped onto the wafer surface from above. At this time, the inside of the chamber is processed in a clean N ₂ atmosphere. The pressure is normal pressure. 4. From the top, spray ultrapure water on the wafer surface with a drop-type ultrasonic wave. Processed under a normal pressure in a clean N ₂ atmosphere. 5. Drying (spin drying), processing under reduced pressure. Step 1, 4,000R / M (5~10 seconds) central portion Clean _{N 2} blow step 2, 60R / M (5 to 10 sec) Clean hot _{N 2} blow (120 ° C. or higher) to the entire Step 3, 4, 000R / M (5 to 10 seconds) Entirely clean N ₂ blows 1, 2 are processed in the same chamber, and 3, 4, 5 are processed in the same chamber. Experimental data 1, ashing rate 8 inches wafer, 30, 0
00 Å / min · (when ozone gas is 19%) 2, resist removal after ion implantation, dose amount 10 ¹⁶ ,
Ozone gas 19%, ozone water 30PPM and HF water (0.6%) were able to remove 100%. 3, resist removal after dry etching, 0.18 micron, aspect ratio 8, ozone gas 19%, and ozone water 3
100% removal was possible with 0 PPM and HF water (0.6%).

[Advantages of the Invention] With respect to the ashing apparatus used so far, only a small amount of resist remains. In this method, the residual resist was zero. At the same time, by utilizing this device, it is possible to perform more clean cleaning, and since the drying process is performed in a clean N ₂ gas atmosphere, it is possible to prevent the generation of a natural oxide film during drying. . That is, in this device, the resist can be completely removed, and cleaning and drying can be performed more cleanly in one device.

[Brief description of drawings]

FIG. 1 shows a wafer transfer robot that takes a wafer stored in a cassette and places it in a chamber that uses ozone. Then, after the sealing is completed, the pressure in the chamber is adjusted to 10 Torr by the vacuum pump. Then, the temperature of the wafer is gradually heated to 200 to 240 ° C. From the start of heating, ozone gas is sprinkled while moving from the slit nozzle of 0.1 mm into the wafer surface. After the completion, the pressure inside the chamber is set to normal pressure. Then, add ozone water to 0.1
Spray ozone water while moving from the millimeter slit nozzle into the wafer surface. The transfer robot takes out the wafer and places it in the next chamber. The inside of this chamber is made into a clean N ₂ gas atmosphere, and HF water is sprayed onto the wafer surface from a 0.1 mm slit nozzle. At this time, the wafer is rotating at 30 R / M. After completion, wash with ultrapure water. Process under the same conditions as sprinkling with HF water. After cleaning with ultrapure water, the wafer surface is dried. Drying is performed under reduced pressure using a clean hot N ₂ gas blow. Initially 4000 R / M (5-10 seconds), central clean N ₂ blow, then 60 R / M clean hot N ₂ blow (120 ° C or more) over the entire wafer, and finally 4000 R / M to blow clean N _{2 over the} entire wafer, and after completion, clean N ₂ in the chamber is discharged to create a clean air atmosphere for both loader and unloader. Then, the wafer is placed in a cassette.

[Explanation of symbols]   Cassette containing wafers   Chamber that uses ozone   Chamber using HF water, ultrapure water, drying   Wafer transfer robot

Claims (3)

[Claims] 1. In this apparatus, ozone gas (concentration 12% or more) and ozone water (concentration 3) are used as an ashing function.
This is a system that uses 0 PPM or more) and HF water (concentration of about 0.6%). 2. It can also be used for resist removal in a liquid crystal process. 3. This apparatus has a cleaning plus drying function after the ashing function is completed.