JPH0734435B2 - Assing method and apparatus - Google Patents

Description

The present invention relates to an ashing method and an apparatus for removing an unnecessary film by ashing.

(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.

An ashing process is performed as a process for removing the photoresist film in such a case.

FIG. 2 shows a conventional ashing device, in which an upper chamber 11 provided so as to be movable up and down is raised and a semiconductor wafer 12 is
Is transported from the outside and adsorbed and supported on a hot plate 13 heated to 300 ° C. or higher, and then the upper chamber 11 is processed and connected to the lower chamber 14. In this state, the inside of the chamber is hermetically closed, and ozone generated by the ozone generator 15 flows into the chamber through the ozone introducing pipe 16. The ozone that has flowed in has a plurality of ventilation holes 18 provided in the diffusion plate 17.
Semiconductor wafer heated by hot plate 13 via
Pour over 12. Then, the resist formed on the semiconductor wafer is heated to react with ozone to form carbon dioxide gas and water vapor, and the resist formed on the semiconductor wafer 12 is peeled off and exhausted from the exhaust pipe 19.

The resist is ashed by the above method.

(Problems to be Solved by the Invention) According to the ashing process by the above ashing device, the hot plate is always kept at 300 ° C. or higher, the semiconductor wafer is adsorbed and supported on the hot plate, and ozone is sprayed onto the semiconductor wafer. And the heated resist formed on the semiconductor wafer reacted to peel off the resist.
There is a problem in that the aluminum wiring pattern of the circuit portion formed on the semiconductor wafer is damaged due to heating to 300 ° C. or higher.

Further, if the temperature of the hot plate is set to 300 ° C. or lower, the circuit portion formed on the semiconductor wafer will not be damaged, but the processing time will be delayed.

The present invention has been made in response to the above point, because the uppermost layer formed on one surface of the substrate to be processed is heated by infrared rays, and at the same time, the substrate to be processed is cooled by the cooling plate from the opposite surface of the substrate to be processed. Provided is an ashing method and an ashing method which do not cause a high temperature and do not damage an aluminum wiring pattern formed on a substrate to be processed.

[Structure of Invention]

(Means for Solving Problems) According to the method of the present invention, a substrate to be processed is placed on a mounting table in a processing chamber, and at the same time, an ashing gas containing at least ozone is introduced into the processing chamber, so that the surface of the substrate is processed. The formed resist film is irradiated with infrared rays from an infrared lamp facing the processed substrate to heat the resist film, and at the same time, the resist film is ashed while cooling the processed substrate from the back surface side. And In this case, the irradiation of the infrared lamp may be performed intermittently.

The apparatus of the present invention is an apparatus for placing a substrate to be processed on a mounting table in a processing chamber and introducing an ashing gas containing at least ozone into the processing chamber to ash a resist film formed on the surface of the substrate to be processed. In, an infrared lamp provided to face the substrate to be processed, for irradiating infrared rays to heat the resist film, and a cleaning unit provided on the mounting table for cooling the substrate to be processed from the back surface side. And a plate.

(Function) When the substrate to be processed is irradiated with infrared rays after the ashing gas has flowed into the processing chamber, the substrate to be processed, for example, the semiconductor wafer transmits infrared rays, so that only the film deposited on the upper surface of the semiconductor wafer is heated. Also, since the semiconductor wafer is simultaneously cooled from below by a cooling plate as needed, the semiconductor wafer does not reach a high temperature and the aluminum wiring pattern of the circuit portion formed on the surface of the semiconductor wafer is not damaged.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG.

The processing chamber is composed of a lid-shaped upper chamber 1 and a cup-shaped lower chamber 2, and the upper chamber 1 is provided so as to be movable up and down. The processing chamber is hermetically sealed with the upper chamber 1 and the lower chamber 2 connected to each other. It becomes a state.

A transparent quartz glass window 3 is provided on the upper surface of the upper chamber 1, and the quartz glass windows 3 have a double structure and are arranged side by side with some spacing.

The upper quartz glass window is a sheet of glass, and the lower quartz glass window has a plurality of ventilation holes 4, and the side wall of the upper chamber 1 is penetrated between the two quartz glass windows. An ashing gas, for example, an ozone introducing pipe 6 connected to an ozone generator 5 is provided. Further, an infrared ray, for example, an infrared lamp 7 is arranged in parallel on the quartz glass window 3 above the upper chamber 1.

A cooling means such as a cooling plate 8 is provided at the center of the lower chamber 2 and is connected to a temperature controller (not shown). A plurality of air holes are provided on the surface of the cooling plate 8 so that the semiconductor wafer 9 can be adsorbed and supported on the cooling plate 8. An exhaust pipe 10 for exhausting the inside of the processing chamber is provided below the periphery of the lower chamber 2.

The film deposited on the surface of the semiconductor wafer is peeled off by the following method by the above-mentioned ashing device.

The cooling plate 8 provided in the lower chamber 2 is kept constant at room temperature by a temperature controller (not shown), and the upper chamber 1
Of the semiconductor wafer 9 whose surface has risen and the resist is deposited on the surface thereof is conveyed into the processing chamber and is adsorbed and supported on the cooling plate 8, and then the upper chamber 1 descends and is connected to the lower chamber 2. In this state, the processing chamber is closed.

Next, the ozone generated by the ozone generator 5 flows into between the two quartz glass windows 3 spaced apart at a slight distance via the ozone introducing pipe 6 penetrating the side wall of the upper chamber 1, and the lower quartz It fills the processing chamber through a plurality of ventilation holes 4 of the glass window.

Then, infrared rays are radiated by the infrared lamp 7 provided above the quartz glass window onto the semiconductor wafer 9 adsorbed and supported on the cooling plate 8 in the processing chamber filled with ozone.
Then, the temperature of the resist deposited on the surface of the semiconductor wafer 9 rises to about 400 ° C., while the semiconductor wafer 9 transmits infrared rays, the temperature of the resist does not change but the heat of the resist becomes high. As the temperature rises,
The cooling plate 8 that adsorbs and supports the semiconductor wafer 9 keeps it constant at room temperature.

Then, since the resist is heated to a high temperature, the heated resist reacts with ozone in the processing chamber to form carbon dioxide gas and water vapor, which is exhausted from the exhaust pipe 10.

Since the ozone is harmful, it is decomposed by an ozone decomposer (not shown) connected to the exhaust pipe 10 after exhaust.

As a result of the above, the ashing process is completed, the upper chamber 1 rises, and the semiconductor wafer 9 is transferred to the outside.

In the above-mentioned embodiment, the example in which the infrared irradiation is continuously irradiated within the predetermined period has been described, but the infrared irradiation may be intermittent or the infrared irradiation may be performed by scanning using an infrared beam having an appropriate shape. . In this case, it is possible to selectively irradiate only the portion of the film to be ashed.

As described above, according to this embodiment, since infrared rays pass through the semiconductor wafer, only the film deposited on the surface of the semiconductor wafer can be heated. Therefore, the film deposited on the surface of the semiconductor wafer can be heated. It becomes easy to control the temperature of the product, and the product yield can be improved.

〔The invention's effect〕

As described above, according to the present invention, the substrate to be processed is heated from the front surface side by infrared irradiation, while the substrate to be processed is cooled from the rear surface side, so that ashing can be performed efficiently, and the aluminum wiring pattern is also provided. Since it does not damage the product, the yield of products is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an ashing device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional ashing device. 1,11 ... Upper chamber, 2,14 ... Lower chamber, 3 ... Quartz glass window, 4,18 ... Vent hole, 5,15 ... Ozone generator, 6,16 ...
Ozone introduction tube, 7 ... Infrared lamp, 8 ... Cooling plate, 9, 12 ... Semiconductor wafer, 10, 19 ... Exhaust tube, 17 ... Diffusion plate.

Claims (3)

[Claims] 1. A substrate to be processed is placed on a mounting table in a processing chamber, and an ashing gas containing at least ozone is introduced into the processing chamber to form a resist film formed on the surface of the substrate to be processed. An ashing method comprising irradiating infrared rays from an infrared lamp facing a substrate to heat the resist film and ashing the resist film while cooling the substrate to be processed from the back surface side. 2. The ashing method according to claim 1, wherein the irradiation of the infrared rays is performed intermittently. 3. An apparatus for mounting a substrate to be processed on a mounting table in a processing chamber and introducing an ashing gas containing at least ozone into the processing chamber to ash a resist film formed on the surface of the processing substrate. In, an infrared lamp that is provided so as to face the substrate to be processed and that irradiates infrared rays to heat the resist film, and a cooling provided to the mounting table to cool the substrate to be processed from the back side. An ashing device comprising: a plate.