JP2006173260A - Semiconductor device and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a semiconductor device conducting a treatment destaticizing a semiconductor substrate before a wet etching treatment and the device. <P>SOLUTION: An element isolation insulating film 2 is formed on the semiconductor substrate 1 in Fig.(a), and a gate insulating film 6 is deposited. A photo-resist 7 is formed in Fig.(b), and the semiconductor substrate 1 is irradiated with a light 9 and a destaticizing is conducted in Fig.(c) for removing charges 8 generated by a pure-water washing or the like. Lastly, the gate insulating film 6 is removed selectively while using the photo-resist 7 as a mask in Fig.(d). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for manufacturing a semiconductor device in which an insulating film is removed by wet etching, and more particularly to a method and an apparatus for manufacturing a semiconductor device that perform static elimination when removing an extremely thin insulating film.

  In a conventional process of removing an insulating film made of an oxide film and a nitride film, charges are generated due to a cleaning process after ion implantation and environmental factors. Thereafter, when the insulating film is removed with a chemical such as dilute hydrofluoric acid, the insulating film is thinned to about 10 nm with the recent miniaturization. It becomes thin and temporarily has a very high electric field strength. As a result, a dielectric breakdown of the insulating film occurs, causing a problem of causing a substrate defect when charges are released to the semiconductor substrate.

  A specific example will be described below. The process of selectively removing the insulating film using a photoresist as a mask is often used for forming a dual gate insulating film. After forming an element isolation insulating film on the semiconductor substrate by a known technique, a gate insulating film is deposited on the entire surface of the semiconductor substrate. Thereafter, a photoresist is formed by a known photolithography technique. Since the cleaning after the development processing at this time is performed with pure water having a high specific resistance, electric charges are generated by friction between the insulators. Then, a substrate defect is caused when the gate insulating film is selectively removed with a chemical such as dilute hydrofluoric acid using the photoresist as a mask.

  And a step of forming a resist pattern to leave a predetermined region of the Al-Si metal thin film, and then removing the resist pattern and washing with water for the purpose of preventing corrosion of the metal wiring due to accumulated static electricity. A method of manufacturing a thin film transistor is disclosed that includes a step of removing static electricity accumulated on the surface of an insulating substrate with an ionizer before a wet etching step and a water washing step (see, for example, Patent Document 1).

  Further, a method for manufacturing a semiconductor device is disclosed in which, when a charge charge caused by charged particles occurs during a process such as dry etching, an ultraviolet irradiation process is performed to perform a charge-up neutralization process ( For example, see Patent Document 2).

Japanese Patent Laid-Open No. 7-221311 JP-A-4-152519

  Since the conventional method for manufacturing a semiconductor device has been performed as described above, the substrate generated when the dielectric breakdown of the insulating film occurs during the wet etching process due to the charge generated by cleaning with pure water after forming the photoresist. There has been a problem of causing a substrate defect.

  The manufacturing method of the thin film transistor of Patent Document 1 relates to a process of forming an electrode wiring by etching a metal thin film, and in recent years, this process has shifted from a wet etching process to a dry etching process. On the other hand, in the process of removing the insulating film having the subject of the present invention, dry etching is difficult from the viewpoint of uniformity, selectivity, damage to the substrate, etc. There is no state. Therefore, there has been a demand for a method of eliminating static electricity before the wet etching process.

  The manufacturing method of the semiconductor device of Patent Document 2 is not a method of removing static electricity before the wet etching process, but when a charge-up caused by charged particles occurs during a process such as dry etching, the post-process is performed by ultraviolet irradiation. Static elimination is performed. The effect is limited to a degree that suppresses a decrease in intrinsic lifetime due to deterioration of the oxide film. In addition, the occurrence of the charge-up itself in the same process can be suppressed by various improvements including recent processing conditions.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a method and apparatus for manufacturing a semiconductor device that performs a process of discharging a semiconductor substrate before performing a wet etching process.

  In the method of manufacturing a semiconductor device according to the present invention, the semiconductor substrate is neutralized before the wet etching process is performed on the insulating film on the semiconductor substrate.

  According to the present invention, since the process of removing the charge on the surface of the semiconductor substrate is added before the wet etching process for removing the insulating film with a chemical solution such as dilute hydrofluoric acid, an increase in electric field strength in the wet etching process can be prevented. Thus, it is possible to eliminate defects in the semiconductor substrate and to obtain a semiconductor device having a reduced defect rate and excellent reliability.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below. FIG. 1 is a diagram showing a processing flow of the method for manufacturing a semiconductor device according to the first embodiment. In FIG. 1A, after forming an element isolation insulating film 2 on a semiconductor substrate 1 by a known technique, a gate insulating film 6 is deposited on the entire surface of the semiconductor substrate 1. Subsequently, as shown in FIG. 1B, a photoresist 7 is formed by a known photolithography technique. At this time, since cleaning after development processing is performed with pure water having a high specific resistance, electric charges 8 are generated due to friction between insulators.

  Thereafter, as shown in FIG. 1C, the surface of the semiconductor substrate 1 is irradiated with light 9 with a fluorescent lamp or the like, and the surface is neutralized. FIG. 2 is a correlation graph between the illuminance of the light 9 in FIG. 1 and the defect rate of the semiconductor substrate 1. 2 that the illuminance of the light 9 needs to be at least 200 lux in order to reduce the defect rate. Finally, as shown in FIG. 1D, the gate insulating film 6 is selectively removed with a chemical such as dilute hydrofluoric acid using the photoresist 7 as a mask.

  As described above, according to the first embodiment, the process of removing the charge on the semiconductor substrate surface is added before the wet etching process of removing the insulating film with a chemical solution such as dilute hydrofluoric acid. It is possible to prevent an increase in electric field strength, eliminate defects in the semiconductor substrate 1, and obtain a semiconductor device having an excellent defect rate and reliability.

Embodiment 2. FIG.
The second embodiment of the present invention will be described below. FIG. 3 is a configuration diagram of a developing device including the light irradiation processing mechanism according to the second embodiment. If a mechanism for performing static elimination (FIG. 1C) according to the first embodiment is added to a developing device or a wet etching device, the same effect can be obtained without increasing the number of steps. In FIG. 3, the developing device includes a vacuum chuck 10 that holds the semiconductor substrate 1, a developing cup 11, a developing nozzle arm 12, a developing nozzle 13, a rinse nozzle 14, a light irradiation unit 15, an illuminance meter 16, and an illuminance control unit 17. ing. Except for the light irradiation unit 15, the illuminance meter 16, and the illuminance control unit 17, the configuration of the conventional developing device is the same.

  Next, the operation will be described. The developer is discharged from the developing nozzle 13 while rotating the semiconductor substrate 1 fixed by the vacuum chuck 10. And a developing solution is uniformly apply | coated to the semiconductor substrate 1 surface, and a photoresist is developed. Thereafter, a rinse liquid and pure water are sequentially discharged from the rinse nozzle 14 onto the surface of the semiconductor substrate 1 to complete the development process. Thereafter, light is emitted from the light irradiation unit 15, the illuminance on the surface of the semiconductor substrate 1 is detected by the illuminance meter 16, and the illuminance control unit 17 holds the illuminance at 200 lux or more to perform static elimination.

  FIG. 4 is a configuration diagram in which a light irradiation processing chamber according to Embodiment 2 is separately provided. The light irradiation processing chamber 21 includes the light irradiation unit 15, the irradiometer 16, and the illuminance control unit 17 shown in FIG. 3. Although the light irradiation process is performed in the development processing chamber in FIG. 3, the light irradiation process is performed in the light irradiation processing chamber 21 after the development processing is completed and before the semiconductor substrate 1 is stored in the transport cassette 20 as shown in FIG. 4. Can also be performed.

  As described above, according to the second embodiment, the light irradiation processing mechanism (light irradiation unit 15, illuminance meter 16, illuminance control unit 17) is incorporated in the developing device, or the light irradiation processing chamber 21 is provided. The same effect as in the first embodiment can be obtained without increasing the number.

Embodiment 3 FIG.
The third embodiment of the present invention will be described below. FIG. 5 is a configuration diagram of a wet etching apparatus provided with a light irradiation processing mechanism according to the third embodiment. In FIG. 5, the wet etching apparatus includes a transport cassette 20 for storing the semiconductor substrate 1, a chemical solution layer 23 filled with a chemical solution 22, a drain port 24, an auxiliary drain port 25, a light irradiation unit 15, an illuminance meter 16, and an illuminance control unit. 17 is provided. In addition, except the light irradiation unit 15, the illuminance meter 16, and the illuminance control unit 17, it is a wet etching apparatus of a conventional configuration.

  Next, the operation will be described. First, the semiconductor substrate 1 is irradiated with light from the light irradiation unit 15. The illuminance on the surface of the semiconductor substrate 1 is detected by the illuminance meter 16, and the illuminance control unit 17 holds the illuminance at 200 lux or more, so that the semiconductor substrate 1 is neutralized. Next, the transport cassette 20 containing the semiconductor substrate 1 is placed in the chemical solution layer 23 and sufficiently immersed in the chemical solution 22. When the predetermined time is reached, the transport cassette 20 is taken out from the chemical solution layer 23 to complete the etching process. At this time, if the chemical liquid 22 overflows, it is drained from the auxiliary drain port 25.

  FIG. 6 is a configuration diagram in which a light irradiation processing chamber according to Embodiment 3 is separately provided. In FIG. 6, the semiconductor substrate disposed in the processing standby chamber 26 is stored in the transport cassette 20, and the light irradiation processing chamber 21, the chemical solution processing chamber 27, the pure water processing chamber 28, and the drying processing chamber 29 are sequentially performed by the transport robot 30. Carried. The light irradiation processing chamber 21 is provided with the light irradiation unit 15, the irradiator 16 and the illuminance control unit 17 shown in FIG. In FIG. 5, the light irradiation process is performed by the wet etching apparatus. However, as shown in FIG. 6, the light irradiation process may be performed in the light irradiation process chamber 21 before the semiconductor substrate is carried into the chemical processing chamber 27. it can.

  As described above, according to the third embodiment, the light irradiation processing mechanism (light irradiation unit 15, illuminance meter 16, illuminance control unit 17) is incorporated in the wet etching apparatus, or light irradiation processing is performed before the chemical solution processing chamber 27. By providing the chamber 21, the same effect as in the first embodiment can be obtained without increasing the number of steps.

It is a figure which shows the processing flow of the manufacturing method of the semiconductor device which concerns on Embodiment 1 of this invention. It is a correlation graph of the illumination intensity of the light in FIG. 1, and the defect rate of a semiconductor substrate. It is a block diagram of the developing device provided with the light irradiation processing mechanism which concerns on Embodiment 2 of this invention. It is the block diagram which provided separately the light irradiation process chamber which concerns on Embodiment 2 of this invention. It is a block diagram of the wet etching apparatus provided with the light irradiation process mechanism which concerns on Embodiment 3 of this invention. It is the block diagram which provided separately the light irradiation process chamber which concerns on Embodiment 3 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Semiconductor substrate, 2 Element isolation insulating film, 6 Gate insulating film, 7 Photoresist, 8 Electric charge, 9 Light, 10 Vacuum chuck, 11 Developing cup, 12 Developing nozzle arm, 13 Developing nozzle, 14 Rinse nozzle, 15 Light irradiation unit , 16 illuminance meter, 17 illuminance control unit, 18 development processing chamber, 19 transport arm, 20 transport cassette, 21 light irradiation processing chamber, 22 chemical solution, 23 chemical solution layer, 24 drainage port, 25 auxiliary drainage port, 26 processing standby chamber, 27 Chemical treatment chamber, 28 Pure water treatment chamber, 29 Drying treatment chamber, 30 Transfer robot.

Claims (8)

  A method for manufacturing a semiconductor device, comprising: performing a process of neutralizing the semiconductor substrate before performing a wet etching process on an insulating film on the semiconductor substrate.   2. The method of manufacturing a semiconductor device according to claim 1, wherein in the wet etching process, the insulating film is selectively etched using a photoresist as a mask.   The method for manufacturing a semiconductor device according to claim 1, wherein the process of neutralizing the semiconductor substrate is a light irradiation process.   The method of manufacturing a semiconductor device according to claim 3, wherein an illuminance of light irradiated in the light irradiation process is 200 lux or more. A light irradiation unit for irradiating the semiconductor substrate with light to neutralize the semiconductor substrate;
An illuminometer for detecting the illuminance of the light irradiation;
An illuminance control unit that controls the light irradiation unit from the illuminance detected by the illuminance meter.   6. The apparatus for manufacturing a semiconductor device according to claim 5, wherein the light irradiation unit, the illuminance meter, and the illuminance control unit are incorporated in a developing device or a wet etching device.   6. The semiconductor device manufacturing apparatus according to claim 5, wherein the light irradiation unit, the illuminance meter, and the illuminance control unit are arranged in an independent light irradiation processing chamber.   The illuminance control unit holds the illuminance of the light irradiation at 200 lux or more based on the illuminance of the light irradiation detected by the illuminance meter. An apparatus for manufacturing a semiconductor device according to claim 1.

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