JP2006237360A - Gas cleaning system of semiconductor manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas cleaning system for a semiconductor manufacturing device with remarkable improvement in a cleaning interval for a chamber. <P>SOLUTION: A large amount of heated nitrogen gas is introduced into a chamber 42 at a high temperature at high speed to generate turbulence in the chamber 42. Deposited reaction products, moisture, dust or the like are desorbed in coordination with thermal effects, acquired into a viscous flow of the gas itself, and discharged outside via exhaust lines 9-13 on the side of the semiconductor manufacturing device. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to a gas cleaning system for a semiconductor manufacturing apparatus, and more particularly to a hot gas cleaning system.

  In the semiconductor manufacturing process, film formation, processing, and the like are performed using various reaction gases by plasma CVD (chemical vapor deposition), ion implantation, gas etching, and the like. For example, in a thin film formation process on a semiconductor substrate, chemical vapor deposition (CVD) using plasma, physical vapor deposition (PVD), or the like is used. Even in the vapor phase growth method using plasma, film deposition occurs not only on the substrate but also in the processing chamber and throughout the piping, so the deposited film is peeled off and deposited on the substrate. It is taken into the film or adheres to the substrate surface.

  These peeled contaminants lead to defects in the device that the substrate constitutes, causing problems such as a decrease in device yield and device characteristics.

  In addition, when etching a thin film formed substrate or the like, dry etching or the like is performed in which an etching gas is introduced into the processing chamber, and the introduced gas is turned into plasma to generate radical species. ing. In plasma dry etching, products generated by etching adhere to and deposit everywhere in the chamber. These products are by-products generated by etching and reaction products by reaction between radicalized etching gas substances, and these deposit or form an adhesion film in the chamber.

  The deposited or adhered film gradually grows on the inner wall of the chamber and the surface of each part in the chamber as the etching is repeated, and the film thickness increases. This thickened film eventually peels off and causes particles, deteriorates the reproducibility of the etched shape, or reduces the sensitivity of the end point detector by fogging the viewing window for detecting the end point of the chamber.

  Therefore, in a process such as thin film formation or etching using a process gas, particularly a plasma process gas, it is possible to remove a film adhered or deposited on an unnecessary portion other than the object to be processed in the processing chamber. Necessary. Reaction products in the exhaust gas generated by these processes and the like adhere to the process chamber and the exhaust pipe.

  In order to improve the throughput of the semiconductor manufacturing apparatus, it is important to improve the maintenance frequency. Conventionally, high-frequency wet cleaning is performed in order to remove reaction products adhering to the process chamber and the exhaust pipe. In the wet cleaning, a reaction product to be removed is processed by oxidation / reduction reaction or dissolution. It is necessary to perform processing after the processing apparatus is temporarily stopped and opened to the atmosphere. Furthermore, in order to perform wet cleaning, since there is a limit to the size of the process chamber and exhaust pipe that can be cleaned in the cleaning tank, disassembly and assembly are indispensable.

  Since the cleaning process including disassembly and assembly requires a lot of time and effort, there are attempts to reduce the frequency of wet cleaning and attempts to suppress the formation of reaction products themselves and proposals to prevent the adhesion of reaction products. (For example, refer to Patent Document 1).

In addition to wet cleaning, dry cleaning using a cleaning gas is known. Examples of the cleaning gas include a fluorine-containing material such as CF ₄ , C ₂ F ₆ , SF ₆ , and NF ₃ and a gas containing a chlorine-based material such as Cl ₂ and BCl ₄ . For example, the SiO ₂ deposited in the chamber after the CVD process, the case of removing the cleaning gas containing NF _3, NF ₃ gas is turned into plasma, thereby fluorine radicals are active radical species generated reacts with SiO ₂ SiF ₄ is obtained. As the gas SiF ₄ is exhausted to the outside of the chamber along with the gas flow, the SiO ₂ in the chamber is removed, and the cleaning of the chamber proceeds. The chamber of the processing apparatus includes an exhaust device and is evacuated under reduced pressure so that the inside is maintained at a certain degree of vacuum. The reaction rate of the cleaning gas introduced into the chamber to the contaminants in the chamber is usually as low as about 10%, and most of the expensive gas such as NF ₃ constituting the cleaning gas is not used by the exhaust device. Will be discharged. For this reason, in the dry cleaning of the chamber of the processing apparatus by the cleaning gas, since the utilization efficiency of the cleaning gas is low, it is also proposed to recirculate the cleaning gas (see, for example, Patent Document 2).

  On the other hand, hot gas cleaning systems are also beginning to be used. This cleaning system introduces a large amount of nitrogen gas or inert gas into the chamber at a high temperature and high speed to generate turbulent flow in the chamber. The reaction product, moisture, dust and the like adhering to the heat effect are desorbed, taken into the viscous flow of the gas itself, and discharged to the outside by the exhaust system on the apparatus side.

  However, even when such a hot gas supply device is connected to a semiconductor manufacturing facility as an external device, a desired cleaning effect may not be obtained.

Therefore, there is a demand for the construction of a gas cleaning system that optimizes the connection method and process of the hot gas supply device.
JP 2001-189277 A JP 2003-17416 A

  An object of the present invention is to provide a gas cleaning system of a semiconductor manufacturing apparatus in which the chamber cleaning cycle is greatly improved.

  According to one aspect of the present invention, there is provided a semiconductor manufacturing apparatus that has a vacuum front chamber and a vacuum main chamber and performs a desired process on an object to be processed, and a residue in the semiconductor manufacturing apparatus generated by the desired process. A cleaning gas introduction mechanism that compresses and heats the inert gas to be removed and introduces it into the vacuum front chamber of the semiconductor manufacturing apparatus, and compresses and heats the residue removed from the semiconductor manufacturing apparatus together with the exhaust gas, There is provided a gas cleaning system for a semiconductor manufacturing apparatus comprising an exhaust mechanism for variably exhausting the gas, and a system controller for controlling the cleaning gas introduction mechanism and the exhaust mechanism.

  According to the present invention, there is provided a gas cleaning system for a semiconductor manufacturing apparatus in which the chamber cleaning cycle is greatly improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing a configuration of a gas cleaning system of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

  This gas cleaning system introduces a large amount of heated nitrogen gas or inert gas into the chamber at a high temperature and high speed to generate turbulent flow in the chamber. Reaction products, moisture, dust, etc. adhering to the thermal effect are desorbed, taken into the viscous flow of the gas itself, and discharged to the outside by an exhaust system on the semiconductor manufacturing apparatus side.

  In FIG. 1, an introduction pipe 2 for supplying a cleaning gas is connected to an external device 1. The introduction pipe 2 may be a SUS BA pipe, for example. In the middle of the introduction pipe 2, an air operated valve 3 is disposed as an operation valve for controlling the flow rate. The external apparatus 1 is for supplying hot gas to the semiconductor manufacturing apparatus 4 and is connected to a system controller 5. The system controller 5 controls the cleaning system 100 including an external device. For example, the system controller 5 performs air operation valve control, heater control, interlock control, or process monitoring. The external device 1 is connected to a load lock (vacuum front chamber) chamber 41 of the semiconductor manufacturing apparatus 4 through an introduction pipe 2. The introduction pipe 6 immediately before the load lock chamber 41 is provided with a straight valve 7 having a straight valve body structure and no liquid pool, as a gas introduction part valve. This is because the speed loss of the cleaning gas is reduced with a high flow rate rating characteristic.

  A sensor 8 is disposed in the vicinity of the outlet side of the straight valve 7. This sensor 8 detects the pressure and temperature of hot gas. The introduction pipes 2 and 6 are heated by a heating device (not shown) so that the cleaning gas is heated to a desired temperature and the temperature loss is minimized. The cleaning gas sent into the load lock chamber 41 of the semiconductor manufacturing apparatus 4 is supplied to a process chamber 42 that is a vacuum main chamber of the semiconductor manufacturing apparatus 4. When a large amount of inert gas is introduced into the process chamber 42 at a high temperature and a high speed, a turbulent flow is generated in the process chamber 42. Coupled with the thermal effect of the cleaning gas, reaction products, moisture, dust, etc. adhering in the process chamber 42 are desorbed.

  The outlet side of the process chamber 42 is connected to the exhaust pump and the pump unit 10 via the exhaust pipe 9. The pump unit 10 has a mechanical booster pump (MBP) 11 and an oil diffusion pump (DP) 12 as main components, and variably controls the exhaust speed of the hot gas discharged from the process chamber 42 by the exhaust pump, and has a controller function. is doing. The hump unit is connected to the scrubber 13 via the exhaust pipe 9. The exhaust pipe 9 is heated by a heating device (not shown) so that the temperature loss of the cleaning gas is minimized.

  The entire gas cleaning system configured as described above is controlled by the system controller so that the operations of the external device, the air operated valve, and the interlock can be linked. In other words, the present gas cleaning system monitors the pressure and temperature of each part constituting the system, and keeps a predetermined process always in an appropriate state.

  Next, a cleaning example in the hot gas cleaning system configured as described above will be described.

Nitrogen (N ₂ ) gas was used as the cleaning gas. The inert gas used is not limited to N ₂ but may be Ar or He gas. The flow rate of the N ₂ gas to be supplied is preferably an output of 10 to 300 liters / minute, and is preferably sent in bursts into the chamber. Compared to the conventional N ₂ gas flow rate of 500 to 700 liters / minute, the amount is greatly reduced.

  The introduction pipe was heated at a heater temperature of 90 to 130 ° C. so that the N 2 gas had a temperature of 50 to 85 ° C. at the load lock chamber inlet. Conventionally, a temperature of 100 to 130 ° C. was required at the inlet portion of the load lock chamber, and about 130 ° C. was required at the introduction pipe, so that not only energy efficiency was significantly improved, but even if such temperature was too high, The inconvenience that the cleaning ability cannot be sufficiently exhibited is improved.

  At this time, the system was controlled so that the exhaust speed of the exhaust pump was 500 to 2000 liters / minute. Conventionally, the exhaust pump has been required to have an exhaust speed of 4000 liters / minute or more, so the exhaust pump itself can be reduced in size. In addition, since a large volume of exhaust is no longer necessary, the cleaning system can be prevented from being overcooled.

  In this way, moisture and particles are taken into the introduced viscous flow gas and discharged to the scrubber through the exhaust pipe.

  According to the cleaning system of the present invention, the chamber wet cleaning cycle (MWBC) can be increased from every 1000 processed wafers to 2000 times / times, which is twice as many. In addition, the frequency of cleaning exhaust pipes has been increased from six months to six times per month, and the maintenance frequency has been greatly improved.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

It is a block diagram of the gas cleaning system of the semiconductor manufacturing apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Cleaning system, 1 ... External device, 2 ... Introducing piping, 3 ... Air operation valve, 4 ... Semiconductor manufacturing apparatus, 41 ... Load lock chamber, 42 ... Process chamber, DESCRIPTION OF SYMBOLS 5 ... System controller, 6 ... Introduction piping, 7 ... Straight valve, 8 ... Sensor, 9 ... Exhaust piping, 10 ... Pump unit, 11 ... Mechanical booster pump (MBP) ), 12 ... Oil diffusion pump (DP), 13 ... Scrubber.

Claims (5)

A semiconductor manufacturing apparatus having a vacuum front chamber and a vacuum main chamber, and performing a desired process on a target object;
A cleaning gas introduction mechanism that compresses and heats an inert gas for removing the residue in the semiconductor manufacturing apparatus generated by the desired treatment and introduces it into the vacuum front chamber of the semiconductor manufacturing apparatus;
It comprises: an exhaust mechanism that compresses and heats the residue removed from the semiconductor manufacturing apparatus together with exhaust gas, and exhausts the exhaust speed in a variable manner; and a system controller that controls the cleaning gas introduction mechanism and the exhaust mechanism. Gas cleaning system for semiconductor manufacturing equipment.   2. The gas cleaning system for a semiconductor manufacturing apparatus according to claim 1, wherein the exhaust mechanism includes a pump unit for sending the exhaust gas to the exhaust side and a heater device for heating the exhaust pipe.   2. The system controller according to claim 1, wherein the system controller controls an air operation valve and a heater provided in the cleaning gas introduction mechanism, interlocks the cleaning gas introduction mechanism and the exhaust mechanism, or performs process monitoring. Gas cleaning system for semiconductor manufacturing equipment. The inert gas is N ₂ and is introduced into the vacuum front chamber after being compressed and heated to a temperature of 50 to 85 ° C. at an output flow rate of 10 to 300 liters / minute and at the inlet of the vacuum front chamber. The gas cleaning system for a semiconductor manufacturing apparatus according to claim 1, wherein:   The semiconductor manufacturing apparatus according to claim 5, wherein the inert gas is introduced into the vacuum front chamber by heating an introduction pipe of the cleaning gas introduction mechanism at a heater temperature of 90 to 130 ° C. Gas cleaning system.

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