KR19990026120A - Endpoint Detection System for Semiconductor Devices - Google Patents

Abstract

An end point detection system for a semiconductor device of the present invention includes a chamber in which a wafer is loaded and a predetermined etching process is performed on a process surface of the wafer, and an outside of the chamber, and an etching stop layer in the wafer process surface where the etching process is performed. Hollow cathode lamps with metal cathodes, such as metals, beam drawers that reduce the spot size and divergence of the light generated from the hollow cathode lamps, and transmitting light transmitted from the beam drawers as pulsed light For a chopper, a first window installed on one surface of the chamber and allowing light transmitted through the chopper to be transmitted into the chamber, and light installed on one side of the wafer and transmitted through the first window. A first mirror portion to be reflected to the surface, and the first mirror portion and the wafer are disposed to face each other, and the first mirror portion A second mirror portion for reflecting the light passing through the processing surface of the fur toward one side of the chamber, and a second window provided on one surface of the chamber and allowing the light reflected from the second mirror portion to be transmitted to the outside of the chamber. And a photo multiplier tube installed outside the chamber and receiving light transmitted through the second window, a preamplifier for enlarging the signal transmitted from the photo multiplier tube, and collecting and processing the signal transmitted from the preamplifier. It includes a box car to store.

Description

An endpoint detection system for semiconductor device

The present invention relates to an end point detection system for a semiconductor device, and more particularly to an end point detection system for a semiconductor device for detecting the end point during the etching process in the process of manufacturing the semiconductor device.

An optical method is used as an endpoint detection method during a dry etch process. The optical method finds an end point by observing the emission of plasma generated during the dry etching process using a spectrometer, a photo multiplier tube, or a photo diode. However, this method adjusts the endpoint with etch time because the sensitivity is too low to find the endpoint during contact etch.

To solve this problem, an end point detection system and laser induced fluorescence (LIF) are used to detect the end point by detecting the amount of etched elements in the etch stop layer using a mass spectrometer. An endpoint detection system that detects the amount of elements etched in an etch stop layer using a detection method.

In this case, the endpoint detection system using the mass spectrometer is very sensitive, but it is difficult to obtain data on a specific part of the wafer, and a separate pumping system must be used. There is a problem to be attached. In addition, since a turbo molecular pump or the like must be used for smooth operation of the mass spectrometer, the cost of attaching or purchasing a vacuum device is considerable.

On the other hand, the endpoint detection system using the LIF detection method, unlike the mass spectrometer, has the advantage of obtaining local data by sending a laser to a specific portion of the wafer. However, expensive lasers with varying wavelengths are needed, and observation windows for laser-induced fluorescence must be provided in the etch chamber. In particular, lasers capable of varying wavelengths are expensive to maintain and repair, and require expert personnel.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and an object thereof is to detect data at a relatively low cost and a simple method when detecting an endpoint during an etching process in a process of manufacturing a semiconductor device. To provide an endpoint detection system for a new type of semiconductor device that can be easily found.

1 is a block diagram illustrating an endpoint detection system for a semiconductor device in accordance with an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10 endpoint detection system 12 Hollow cathode lamp

14 Beam Narrow 16: Chopper

18: first window 20: first mirror portion

22: second mirror portion 24: second window

26: photo multiplier tube 28: preamplifier

30: boxcar 32: dual pulse generator

34: wafer 36: chamber

40: light

According to a feature of the present invention for achieving the above object, an endpoint detection system for a semiconductor device comprises: a light source portion having a cathode of a metal, such as a metal of an etch stop layer, in a wafer process surface on which an etching process is performed; A detection portion for receiving the light transmitted from the light source portion and passing through the process surface of the wafer where the etching process is performed; And a light guide portion for allowing the light transmitted from the light source portion to pass to the process surface of the wafer and for the light passing through the process surface of the wafer to be transmitted to the detection portion.

In the present invention, the light source portion includes a hollow cathode lamp for generating predetermined light; A beam narrower to reduce spot size and divergence of light generated from the hollow cathode lamps; And a chopper for transmitting pulsed light to the light guide portion. The lamp is used at conditions of 200 to 240 volts and 8 to 12 amps. The beam narrower consists of a plurality of lenses. The detecting portion includes a photo multiplier tube for receiving light transmitted from the light guide; A preamplifier for amplifying the signal transmitted from the photo multiplier tube; And a box car that collects, processes, and stores the signal transmitted from the preamplifier. The photo multiplier tube is driven by a TTL pulse. The photo multiplier tube can adjust the operating time. The photo multiplier tube includes a spectrometer. The light guide portion is provided on one side of the wafer, the first mirror portion for reflecting the light transmitted from the light source portion to the process surface of the wafer; And a second mirror unit disposed to face the first mirror unit and the wafer therebetween, and configured to transmit the light passing through the process surface of the wafer to the detection unit by the first mirror unit. The first and second mirrors are installed such that light incident from the light source portion passes through the entire process surface of the wafer.

According to another aspect of the present invention for achieving the above object, an endpoint detection system for a semiconductor device includes a chamber in which a wafer is loaded and a predetermined etching process is performed on the process surface of the wafer; A hollow cathode lamp installed outside the chamber and having a cathode of a metal, such as a metal of an etch stop layer, on the wafer process surface on which an etching process is performed; A beam narrower to reduce spot size and divergence of light generated from the hollow cathode lamps; A chopper for transmitting the light transmitted from the beam narrower into pulsed light; A first window installed on one surface of the chamber and configured to transmit light transmitted through the chopper into the chamber; A first mirror unit disposed on one side of the wafer and configured to reflect light transmitted through the first window to a process surface of the wafer; A second mirror unit installed to face the first mirror unit and the wafer therebetween, and reflecting the light passing through the process surface of the wafer toward one side of the chamber by the first mirror unit; A second window installed on one surface of the chamber and configured to transmit light reflected from the second mirror to the outside of the chamber; A photo multiplier tube installed outside the chamber and configured to receive light transmitted through the second window; A preamplifier for amplifying the signal transmitted from the photo multiplier tube; And a box car that collects, processes, and stores the signal transmitted from the preamplifier.

Such a present invention includes a dual pulse generator electrically connected to the chopper and the photo multiplier tube and simultaneously operating the photo multiplier tube only when light is irradiated by simultaneously adjusting the chopper and the photo multiplier tube. The first and second windows are made of quartz.

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

Referring to FIG. 1, an endpoint detection system 10 for a semiconductor device in accordance with an embodiment of the present invention is a metal such as a metal of an etch stop layer in the process of wafer 34 where an etching process is performed. A light source portion having a cathode, a detection portion receiving light transmitted from the light source portion and passing through a process surface of the wafer 34 in which an etching process is performed, and light transmitted from the light source portion includes the wafer ( And a light guide portion that passes through the process surface of 34 and passes through the process surface of the wafer 34 to the detection portion.

In this case, the light source portion may reduce the spot size and the divergence of the light generated from the hollow cathode lamp 12 and the hollow cathode lamp 12. A beam narrower 14 and a chopper 16 for transmitting light in the form of pulses to the light guide portion. In addition, the lamp 12 is used under the conditions of 200 to 240 volts and 8 to 12 amp, and the beam narrower 14 is composed of a plurality of lenses.

On the other hand, the detection portion is a photo multiplier tube 26 for receiving the light transmitted from the light guide and a pre-amp for enlarging the signal transmitted from the photo multiplier tube 26 ( 28 and a boxcar 30 for collecting, processing and storing the signal transmitted from the preamplifier 28. At this time, the photo multiplier tube 26 is driven by a TTL pulse (transistor-transistor-logic pulse), it is possible to adjust the operating time. The photomultiplier tube 26 may include a spectrometer to select light having a specific wavelength.

On the other hand, the light guide portion is provided on one side of the wafer 34, the first mirror portion 20 and the first to reflect the light transmitted from the light source portion to the process surface of the wafer 34 It is installed so as to face each other with the mirror portion 20 and the wafer 34 therebetween, so that the light passing through the process surface of the wafer 34 by the first mirror portion 20 is transmitted to the detection portion. It is comprised by the 2nd mirror part 22. As shown in FIG. In this case, the first and second mirrors 20 and 22 are installed such that light incident from the light source portion passes through the entire process surface of the wafer 34.

Referring back to FIG. 1, in more detail an endpoint detection system for a semiconductor device in accordance with an embodiment of the present invention, the endpoint detection system 10 is loaded with a wafer 34 to process the wafer 34. A chamber 36 having a predetermined etching process on a surface thereof, and a cathode of a metal, such as a metal of an etch stop layer, in the process surface of the wafer 34 which is installed outside the chamber 36 and in which the etching process is performed. Pulses transmitted from the hollow cathode lamp 12, the beam drawer 14 to reduce the spot size and the divergence of the light generated from the hollow cathode lamp 12, and the beam drawer 14 A chopper 16 for transmitting light of a form, and a first window installed on one surface of the chamber 36, the light transmitted through the chopper 16 is transmitted to the interior of the chamber 36 ( 18) and one side of the wafer 34 First mirror portion 20, the first mirror portion 20, and the wafer 34 to reflect light transmitted through the first window 18 to the process surface of the wafer 34. Is installed to face each other, and the second mirror unit reflects the light passing through the process surface of the wafer 34 by the first mirror unit 20 toward one side of the chamber 36. And a second window 24 provided on one surface of the chamber 36 to allow the light reflected from the second mirror portion 22 to be transmitted to the outside of the chamber 36. A photo multiplier tube 26 which is provided outside of the 36 and receives light transmitted through the second window 24, and a preamplifier 28 which enlarges a signal transmitted from the photo multiplier tube 26; ) And a box car 30 for collecting, processing and storing the signal transmitted from the preamplifier 28. .

At this time, the photo multiplier tube 26 is electrically connected to the chopper 16 and the photo multiplier tube 26, and only when the light is irradiated by simultaneously adjusting the chopper 16 and the photo multiplier tube 26. A dual pulse generator 32 is provided to enable operation, and the first and second windows 18 and 24 are made of quartz.

In such endpoint detection systems for semiconductor devices, the hollow cathode lamp is intended to emit light corresponding to a particular atomic absorption line of most metal elements. In other words, light having specific atoms is generated depending on the type of the cathode. Thus, using a cathode of the same type as the metal of the etch stop layer can generate light for use in an endpoint detection system for a semiconductor device.

For example, a titanium hollow cathode lamp emits a strong emission of titanium atoms. The light emitted from the light source is changed into light having a small spot size and divergence as it passes through the beam lower, and proceeds to the first mirror part installed inside the chamber through the first window attached to the chamber. The light incident on the first mirror part passes through the upper surface of the wafer, that is, the process surface while repeating between the second mirror part and the first mirror part. At this time, the titanium atoms in the interior of the chamber absorbs the light passing through and weakens the light intensity. The change in the intensity of light is measured using a photomultiplier tube with high sensitivity after selecting a desired wavelength with a spectrometer.

On the other hand, if there is no titanium atom inside the chamber and light reaches 100 and reaches the photomultiplier tube, when titanium atom is present, less than 100 light reaches the photomultiplier tube, and the amount reached reaches the titanium in the chamber. The more atoms there are, the fewer they are. In this case, when the titanium atoms in the chamber are very small, the absorption degree of light cannot be distinguished, so that the light path is further lengthened by adjusting the angle of the light incident on the first mirror, so that a small amount of titanium atoms has several photons. to absorb photons.

Meanwhile, in order to increase the signal and noise ratio, a pulsed light source and a pulse detection method are used using a double pulse generator, and a signal and noise ratio are increased by using a preamplifier and a box car.

By applying the present invention as described above, it is possible to detect the endpoint of the semiconductor device with little expense. The light sources can be easily exchanged by using a cathode of a metal such as the metal of the etch stop layer of the wafer. It may also be used for endpoint detection in all dry etching processes where metal atoms are present in the etch stop layer.

Claims (13)

An endpoint detection system for a semiconductor device, A light source portion having a cathode of a metal, such as a metal of an etch stop layer, on a wafer process surface on which the etching process is performed; A detection portion for receiving the light transmitted from the light source portion and passing through the process surface of the wafer where the etching process is performed; And a light guide portion for allowing light transmitted from the light source portion to pass to the process surface of the wafer and for light to pass through the process surface of the wafer to the detection portion. Detection system. The method of claim 1, The light source portion includes a hollow cathode lamp for generating predetermined light; A beam narrower to reduce spot size and divergence of light generated from the hollow cathode lamps; And a chopper for transmitting pulsed light to the light guide portion. The method of claim 2, And said lamp is used at conditions of 200 to 240 volts and 8 to 12 amps. The method of claim 2, And said beam narrower is comprised of a plurality of lenses. The method of claim 1, The detecting portion includes a photo multiplier tube for receiving light transmitted from the light guide; A preamplifier for amplifying the signal transmitted from the photo multiplier tube; And a box car that collects, processes, and stores the signal transmitted from the preamplifier. The method of claim 5, And said photo multiplier tube is driven by a TTL pulse. The method of claim 5, And the photo multiplier tube is adjustable in time of operation. The method of claim 5, And said photomultiplier tube comprises a spectrometer to select light of a particular wavelength. The method of claim 1, The light guide portion is provided on one side of the wafer, the first mirror portion for reflecting the light transmitted from the light source portion to the process surface of the wafer; And a second mirror unit disposed to face the first mirror unit and the wafer therebetween, and configured to transmit light passing through the process surface of the wafer to the detection unit by the first mirror unit. An endpoint detection system for a semiconductor device. The method of claim 9, And the first and second mirror portions are provided such that light incident from the light source portion passes through the entire process surface of the wafer. An endpoint detection system for a semiconductor device, A chamber in which a wafer is loaded and a predetermined etching process is performed on a process surface of the wafer; A hollow cathode lamp installed outside the chamber and having a cathode of a metal, such as a metal of an etch stop layer, on the wafer process surface on which an etching process is performed; A beam narrower to reduce spot size and divergence of light generated from the hollow cathode lamps; A chopper for transmitting the light transmitted from the beam narrower into pulsed light; A first window installed on one surface of the chamber and configured to transmit light transmitted through the chopper into the chamber; A first mirror unit disposed on one side of the wafer and configured to reflect light transmitted through the first window to a process surface of the wafer; A second mirror unit installed to face the first mirror unit and the wafer therebetween, and reflecting the light passing through the process surface of the wafer toward one side of the chamber by the first mirror unit; A second window installed on one surface of the chamber and configured to transmit light reflected from the second mirror to the outside of the chamber; A photo multiplier tube installed outside the chamber and configured to receive light transmitted through the second window; A preamplifier for amplifying the signal transmitted from the photo multiplier tube; And a box car that collects, processes, and stores the signal transmitted from the preamplifier. The method of claim 11, And a dual pulse generator electrically connected to the chopper and photo multiplier tubes and simultaneously adjusting the chopper and photo multiplier tubes such that the photo multiplier tube is activated only when light is irradiated. Endpoint detection system. The method of claim 11, And said first and second windows are made of quartz.