JP2002367966A - Semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is extremely difficult to measure the amount of deposition without opening a treatment chamber, and it is difficult to carry out a deposit film removal process appropriately. SOLUTION: Probe light is transmitted to a fiber 106 where deposition 111 is adhering, thus obtaining the amount of the deposition 111 that adheres onto the surface of the fiber 106, by measuring the amount of attenuation of light with a specific wavelength with a spectrophotometer 110.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly, to an apparatus for easily measuring the amount of deposited film formed in a processing chamber during a manufacturing process.

[0002]

2. Description of the Related Art In an etching apparatus for a semiconductor manufacturing process, a reaction product formed by a reaction between a gas used in an etching process and a substance to be etched is exhausted by an exhaust system attached to a processing chamber. Without cutting, they adhere to and accumulate on the inner wall of the etching processing chamber and the surface of the component (hereinafter referred to as deposits). When the etching process is repeated, the deposited film gradually thickens and peels off from the adhering part (the surface of the component in the processing chamber).
Drops on the wafer cause dust contamination and cause poor etching. Further, a specific gas is generated from these deposited films, and the process becomes unstable, so that the reproducibility of the etching cannot be obtained. As a result, there is a problem that the yield is reduced.

[0003] Therefore, when deposits reach a certain amount, they must be removed. For example, a process for removing deposits in a processing chamber by generating a specific plasma is performed. At times, the processing chamber is opened to the atmosphere to clean and clean internal components.

[0004] However, these operations cause a reduction in the price competitiveness of semiconductor devices due to a reduction in device production efficiency, and therefore, it is necessary to reduce the work as much as possible. Therefore, it is important to monitor the amount and state of the deposited film in order to determine when to perform these operations and to determine the effect.

As a method of monitoring a deposited film, for example, as described in JP-A-7-86254, infrared light is transmitted through an internal reflection prism installed in a processing chamber, and the transmitted light is spectrally analyzed. There is a method of estimating the amount of sediment from the amount absorbed by sediment.

[0006]

However, since it is technically difficult to reduce the size of the prism to several millimeters or less,
It could not be installed in an area that is apt to be spatially restricted, such as near the wafer. Further, since the prism has no mechanical flexibility, there is a great restriction when the prism is mounted on a curved portion in the processing chamber. Further, although an optical fiber is connected to the prism to supply light, it is difficult to reduce the connecting portion to several millimeters or less, and there is also a problem in mechanical strength reliability.

[0007]

SUMMARY OF THE INVENTION A fiber which is transparent to a specific wavelength absorbed by a deposit and is mechanically flexible is installed at a position where the deposit is formed in the processing chamber, and the fiber is specified. Probe light including light of a wavelength is transmitted through the fiber. By measuring the amount of attenuation at a specific wavelength, the amount of deposits adhering to the fiber surface is monitored, and the amount of deposits at that location in the processing chamber is estimated.

[0008]

FIG. 1 shows an embodiment of a fiber-based deposit monitor.

A process is performed by placing a wafer 102 on a wafer table 103 in a processing chamber 101. The processing chamber 101 is provided with a flange 104 that is kept airtight so that vacuum evacuation can be performed. A light guide path 105 is provided in the flange 104, and this portion is also kept airtight. A fiber 106 is connected to the vacuum side of the light guide 105 by a connector 107, and probe light required for monitoring is supplied to the light guide 10
It can pass between 5 and the fiber 106.
A light guide cable 108 is also connected to the air side of the light guide path 105 via a similar connector, so that probe light can be exchanged with the light source 109 or the spectrometer 110.

The probe light emitted from the light source 109 is supplied to a light guide cable 108, a light guide path 105, a fiber 106, a light guide path 105,
After passing through the light guide cable 108 in this order, the attenuation is measured by the spectrometer 110.

As the fiber, for example, a sapphire fiber having a diameter of 0.15 mm can be used. Since sapphire has high corrosion resistance and is thermally stable up to about 2000 degrees, it can be used in a plasma process using a corrosive gas. In addition, the radius of curvature is 10
Since it does not break even if it is bent to about mm, the handling is good and the restrictions on the installation place are relatively small. Since sapphire can transmit infrared light having a wavelength of about 4 microns or less, it is possible to monitor deposits such as silicon nitride and hydrocarbons.

The light guide cable 108 used on the atmosphere side includes:
For example, chalcogenide fibers can be used. Although chalcogenide is inferior to sapphire in corrosion resistance and heat resistance, it has a high light transmission efficiency and is therefore a material that is convenient for transmitting probe light in the atmosphere.

By using a stainless steel SMA connector or the like as the connector 107, the influence of corrosion can be minimized. When installing or replacing the fiber, the fiber is separated from the connector 107.

As the light source 109 and the spectrometer 110, for example, a Fourier transform infrared spectrometer in which they are integrated can be used. A light source having a wavelength of 2.5 to 25 microns is emitted from a light source that is a tungsten filament, and the light that returns through a fiber or the like is separated, and the intensity of light at each wavelength is measured.

The fiber is mechanically flexible,
The inside of the processing chamber 101 can be handled relatively without restriction. In the present embodiment, the deposit 111 formed on the side surface of the wafer table 103 is monitored, but the deposit formed on the surface of the fiber 106 in other portions may be monitored. In such a case, the surface of the fiber 106 is coated with a photoresist or the like, and the coating is removed only on the side of the wafer table 103. Then, the value remaining after subtracting the measurement result before the process from the result measured after the process is
This is due to the deposits formed on the area where the coating was removed.

The probe light emitted from the light source 109 is supplied to a light guide cable 108, a light guide path 105, a fiber 106, a light guide path 105,
After passing through the light guide cable 108 in order, it is measured by the spectrometer 110.From this attenuation, the amount of the deposit 111 adhered to the surface of the light guide cable 108 is obtained, and the inside of the processing chamber 101 in which the fiber is installed is obtained. It is possible to estimate the amount of the sediment formed in the specific region. FIG. 2 shows the detection of the deposit on the fiber surface. The probe light 202 transmitted through the inside of the fiber 201 is transmitted through the fiber while repeating internal reflection on the fiber surface.
Due to the evanescent effect, a specific wavelength is absorbed by the deposit 203 in the vicinity of the portion where the deposit 203 is in contact with the surface of the fiber 201 when the light is internally reflected below the surface to which the 3 is attached. The amount of absorption is proportional to the thickness of the deposit 203 when the thickness of the deposit 203 is equal to or less than the length of the specific wavelength. The change in the thickness of the object 203 can be known.

Although the present embodiment is used for monitoring a deposit, it may be used for monitoring a film forming amount in a film forming apparatus or the like. In addition, by coating the surface of the fiber with a specific material in advance and monitoring the change in the coating thickness with this method,
It is also possible to monitor the etching amount of a specific material in the processing chamber.

[0018]

As described above, by measuring the deposited film thickness, the amount of the film formed during the etching process and deposited in the processing chamber can be monitored without opening the processing chamber. This makes it possible to perform an appropriate process for removing the deposits and clean the inside of the processing chamber, and to reduce dust generated from the deposited film, thereby preventing defective device fabrication. Thus, finer processing becomes possible. Further, it leads to an improvement in yield and a reduction in production cost of semiconductor devices.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a fiber-based deposit monitor.

FIG. 2 is a diagram illustrating detection of a deposit on a fiber surface.

[Explanation of symbols]

101: Processing chamber, 102: Wafer, 103: Wafer stand, 104: Flange, 105: Light guide path, 106: Fiber, 107: Connector, 1
08… Light guide cable, 109… Light source, 110… Spectrometer, 111
... deposits, 201 ... fiber, 202 ... probe light, 203 ... deposits.

Claims (2)

[Claims] In a semiconductor manufacturing apparatus for performing a wafer processing process in a processing chamber, a probe including light having a wavelength absorbed by the deposit to estimate an amount of the deposit formed in a specific region in the processing chamber. A fiber capable of transmitting light is set in the specific area, and the amount of deposits formed on the fiber surface is monitored by measuring the amount of attenuation of the probe light transmitted through the fiber. Semiconductor manufacturing equipment. 2. The semiconductor manufacturing apparatus according to claim 1, further comprising: a light guide path through which the probe light can pass, and an airtight flange for vacuum provided in the processing chamber. A semiconductor manufacturing apparatus characterized in that, when the above-mentioned fiber is consumed, only the above-mentioned fiber can be replaced by connecting via a connector which is detachable and allows probe light to pass therethrough.