JPS602773B2 - How to remove photoresist film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing a photoresist film deposited on a substrate to be processed such as a semiconductor substrate.

Silicon (S) is used to replace counterfeit semiconductor devices such as semiconductor integrated circuits (ICs).
When forming on a semiconductor substrate such as I), for example, after forming an insulating film such as silicon dioxide (Si02) on a Si substrate, a photoresist film is deposited on the oxide film, and the photoresist film is patterned into a predetermined pattern. Using the patterned photoresist film as a mask, the underlying oxide film is etched and shaped into a predetermined pattern, and then a specific element-forming impurity is introduced into the Si substrate using the patterned oxide film as a mask. A process is being taken to make a semiconductor device.

Here, the photoresist film needs to be removed after the selective etching of the oxide film and before proceeding to the next step. As one means for removing such a photoresist film, the semiconductor substrate having the photoresist film is inserted into a reaction tube, and then the reaction gas introduced into the reaction tube is excited with high frequency power to generate gas plasma. A gas plasma treatment method is used in which a photoresist film is incinerated by irradiation with . This plasma treatment method uses sulfur (Japanese 2S04
There is no need to use processing liquids such as ), and therefore there is no operational risk associated with using such processing liquids.

Furthermore, it eliminates the problem of waste liquid treatment after removal treatment, and has advantages such as being able to form fine patterns, so it is widely used in semiconductor manufacturing processes.

In order to efficiently excite the ashing gas introduced into the reaction tube, the frequency of a high-frequency power source has recently been increased, for example, a microwave oscillator has been used.

Conventionally, when removing a photoresist film deposited on a substrate to be processed using a microwave oscillator, the substrate to be processed is inserted into a reaction vessel, the inside of the vessel is evacuated, and then gas plasma is applied. Oxygen for generation (02
) gas was introduced, and then microwaves were irradiated into the reaction vessel to generate oxygen gas plasma, and the photoresist film on the substrate to be processed was incinerated and removed by this oxygen gas plasma.

However, as mentioned above, there are problems such as the need to increase the strength of the reaction container in order to evacuate the interior of the reaction container, and the need for equipment such as a pump for evacuating the reaction container.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a method for effectively ashing and removing photoresist on a substrate to be processed by introducing oxygen gas as a reaction gas without evacuating the inside of a reaction vessel. It is something to do.

A method for removing a photoresist film to achieve this purpose involves inserting a substrate covered with a photoresist film into a reaction tube, and then introducing an oxidizing gas into the reaction tube without evacuating the inside of the reaction tube. Then, the substrate to be processed is heated by irradiation with microwaves, and the photoresist film is ashed and removed. An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram of a processing apparatus for implementing the photoresist film removal method of the present invention.

In the figure, 1 is a reaction tube made of quartz that houses a substrate 2 to be processed (IJ silicon (Si)) whose surface is coated with a photoresist film to be removed; are placed on a quartz substrate holder 3 with their main surfaces facing each other. The reaction tube 1 is provided at its upper portion with a gas introduction tube 4 for introducing, for example, oxygen (02) gas, and a discharge tube 5 for discharging the used gas. One end of the reaction tube is sealed, the other end is open to allow the substrate holder to be taken in and taken out, and the other end can be sealed with a cap 6 made of quartz, for example. The cap 6 is adapted to be attached to the crab body 7. Further, in the upper part of the reaction tube, a microwave oscillator 8 for heating the substrate by oscillating high frequency waves is installed approximately at the center in the longitudinal direction of the lotus body. Furthermore, the reaction tube 1 is attached to the coating body 7 by a support 9. According to the present invention, in such a resist film removing apparatus, a silicon (Si) substrate 2 having a diameter of 4 cm and having a photoresist film (trade name OMR manufactured by Tokyo Ohka Co., Ltd.) coated with a thickness of 1 [mountain surface] is used. After installing the substrate holder 3, the cap 6 is opened and the substrate holder 3 is inserted into the reaction tube 1.

After that, instead of introducing gas, while introducing 02 gas at a flow rate of 10 [so/min], the microwave oscillator 8 with a frequency of 2.45 [GKz] was operated at an output of 600 [W] to irradiate the inside of the reaction tube with microwaves. do. As a result, the number of substrates to be processed is 1 to 2.
After 30 minutes, the temperature reaches a temperature of about 400 CO], and after 30 minutes, the photoresist film deposited on the unprocessed substrate is ashed and removed. In this case, since the main component of the photoresist film is carbon (C), when the substrate is rapidly heated by microwave irradiation, the 02 gas introduced from the gas introduction pipe and the first equation A reaction as shown in the following occurs and the result is C+. 21C.

2. ．． ．． ．． ．． ．． (1) The photoresist film is ashed and removed.

The carbon gas (C02) generated in this manner is discharged to the outside from the gas exhaust pipe 5. If the photoresist film deposited on the substrate is removed by ashes using the method described above, there is no need to evacuate the inside of the reaction tube as in the conventional method, making the equipment simple and inexpensive. The surface of the substrate is rapidly heated by the irradiation, and the photoresist film on the processed substrate is carbonized and removed in a short time, so the substrate surface is less likely to be damaged by the impact of the oxygen gas plasma. The advantage is that the characteristics of the formed semiconductor device are improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram for explaining the photoresist film removal method of the present invention.

In the figure, 1 is a reaction tube, 2 is a substrate, 3 is a substrate holder,
4 is a gas introduction pipe, 5 is a gas discharge pipe, 6 is a cap, 7 is a protrusion, and 8 is a microwave oscillator.

Younger brother 1

Claims (1)

[Claims] 1. Insert a substrate to be processed covered with a photoresist film into a reaction tube, then introduce oxygen gas into the reaction tube without reducing the pressure inside the reaction tube, and then introduce the oxygen gas while irradiating the substrate with microwaves. A method for removing a photoresist film, characterized in that the photoresist film is ashed and removed by a reaction between a gas and the resist film.