JPS6318630A - Method for removing organic coating - Google Patents

Abstract

PURPOSE:To remove rapidly a coating from a substrate, by injecting high- concentration ozone while heating the substrate to a temperature higher than a particular level. CONSTITUTION:A semiconductor substrate carried on a substrate supporting device 2 in a processing chamber 1 is heated by a heater 4 to a temperature of 280 deg.C or more at which ozone is thermally decomposed. High-concentration ozone is injected into the processing chamber through an ozone supply tube 5 and a nozzle 7 so that a coating on the substrate, such as a resist film of the like, is removed rapidly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for removing an organic film in a dry state, and particularly to a method for removing a resist film used in the manufacture of semiconductor devices.

(Prior art) When manufacturing semiconductor devices, a resist film treated with photo processing technology, X-ray irradiation, electron beam irradiation, etc. is used as a mask to perform etching or other processing on a base material such as silicon. It is necessary to remove the resist film.

The resist film is removed by a wet process performed by immersing it in an oxidizing liquid, or by a dry process using oxygen plasma, ultraviolet rays, ozone, etc.

Wet processing using a solution has problems in waste liquid treatment, and fine impurities contained in the liquid have an adverse effect on semiconductor devices, so there is an increasing demand for dry processing.

The method using oxygen plasma, which is the mainstay of dry processing, can cause damage to semiconductor devices due to the plasma.
Removal methods using ozone and ultraviolet rays are attracting attention.

(Problems to be Solved by the Invention) A technique for removing an organic film while heating a semiconductor substrate in a housing supplied with ozone is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 52-20766.

In the method disclosed in this application, as a result of the supplied ozone coming into contact with the heating means 81 and the inside of the apparatus which has reached a high temperature, thermal decomposition of ozone occurs, and the supplied ozone does not work effectively. Therefore, [the optimal range for photoresist removal by ozone treatment is 200'C-2
The bottom layer is heated to a temperature of 50'C. If the underlayer temperature is maintained below 200'C, the photoresist removal rate tends to become too slow, and a similar characteristic is exhibited above about 260'C, where the photoresist removal rate begins to slow again. In this latter case, 260'
It is theorized that at temperatures above 2°C, the ozone molecules cannot be decomposed by the heat from the "hot plate" provided in the underlying photoresist layer before the ozone actually contacts the photoresist material. ” (Japanese Unexamined Patent Publication No. 52-20766 No. 11
It was thought that the maximum removal rate could be increased by 1 by setting the temperature to 200° C. to 250° C., as described in (line 19 of the upper right column of the page to line 10 of the lower left column of the same page).

However, even in such a temperature range, it has not been possible to obtain a commercially satisfactory removal rate. Furthermore, in the process of manufacturing semiconductor devices, when ions of boron and phosphorus are implanted, it takes an extremely long time to remove the photoresist using ozone.

(Means for Solving the Problems) The present inventors have found that the above-mentioned Japanese Patent Application Laid-Open No. 52-20766 describes it as unfavorable, and that other documents (Gmel
1Kflandbuch der Anorgani
It was discovered that the removal rate of the organic film could be increased by supplying a high concentration of ozone in the temperature range where the thermal decomposition of ozone occurs almost completely in the sch. It was.

Hereinafter, the present invention will be explained based on the accompanying drawings.

FIG. 1 is a diagram showing an apparatus for removing organic matter according to the method of the present invention, in which a substrate support device 2 on which a semiconductor substrate 3 to be processed is placed is necessarily provided in the processing chamber 1. A heating device 4 is provided.

The rotation of the substrate support device may be increased in order to eliminate unevenness in processing and increase processing speed.

There is a highly concentrated ozone supply pipe 5 in the process.

The supply pipe is surrounded by a cooling pipe 6. The ozone supply pipe is connected to a plurality of nozzles 7 that inject ozone onto the semiconductor substrate, and the nozzles are provided with pores 8 that pass through the cooling pipe.

Various materials can be used for the constituent materials including the treatment tube, ozone supply pipe, nozzle, etc., as long as they are resistant to ozone corrosion, such as stainless steel.

Further, the shape of the cooling medium supply pipe can be cylindrical or square, and the number of nozzles can be appropriately set depending on the size of the substrate to be processed.

Although the diameter of the nozzle can be determined as appropriate, it is preferable to set it to less than 2 mm.

Ozone is generated by supplying pure oxygen to an ozone generator 9 using silent discharge, but it is preferable to use an ozone generator that uses creeping corona discharge, which is small and has high ozone generation efficiency. After the ozone acts on the substrate during the process, it is decomposed in the ozone decomposition device 1O.

(Function) The removal rate of organic matter can be improved by injecting highly concentrated ozone while heating the substrate to be processed above 280'C, which is the temperature at which ozone almost completely thermally decomposes.

(Example) Tokyo Ohka Kogyo (
Co., Ltd. positive photoresist 0)-PR-800 at 1.5
μTrL was applied and prebaked at 80'C for 30 minutes.

This photoresist-coated silicon substrate was placed on a sample support device, and while the substrate was being heated, ozone was injected onto the substrate from a nozzle with an inner diameter of 0.5# at a flow rate of 10 L/min. The removal rate (A>(B) and (C) of the organic film relative to the substrate temperature when the ozone concentration is 2.5%, 3.5%, and 4.5%, respectively (A>(B) and (C)) is As shown in the figure.

(Effect of the invention) In the method for removing the formal coating jFu from a substrate on which an organic film has been formed, ozone almost completely thermally decomposes the substrate.
By injecting high-temperature ozone while heating the photoresist to a temperature of 80'C or higher, the removal rate of photoresist can be improved, and the ion implantation process, which takes an extremely long time to remove using conventional methods, can be improved. The applied photoresist can also be removed at a practical processing speed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an apparatus for removing organic matter according to the method of the present invention. FIG. 2 shows the relationship between the removal rate of the organic film and the temperature when the ozone concentration is maintained at a constant value. 1, ... Processing 2, ... Substrate support device 3, ... Semiconductor substrate 4, ... Heating device 5, ... Ozone supply pipe 6, ... Cooling pipe 7, ... Nozzle 8, ... Pore 9, ... Ozone generator 10, ... Ozone decomposition device special δ'F Applicant Chlorin Engineers Co., Ltd. Figure 1 Figure 2 Procedural amendment (voluntary) October 1988 9th of the month

Claims (1)

[Claims] 1. In a method for removing an organic film from a substrate on which the film has been formed, the substrate to be processed in a processing chamber is heated to 280° C. or higher from the surface on which the film is not formed, and a high concentration A method for removing an organic film, characterized by spraying ozone. 2. The method for removing an organic film according to claim 1, which comprises injecting highly concentrated ozone onto the surface of the organic film from the pores of a cooled nozzle.