JPS5866838A - Plasma monitor apparatus - Google Patents

Abstract

PURPOSE:To measure the distribution of a chemical seed with high accuracy, by irradiating the laser light having the energies larger and smaller than a half of exciting energy of said chemical seed at right angles to the specific chemical seed containing in plasma and detecting the light of the chemical seed at a crossing point. CONSTITUTION:Lasers 3, 3', a laser light scanning device 6 and a luminous detection device 11 are fixed on an optical stand 7 so that a laser light 4 is crossed nearly at right angles to a laser light 4' emitted from the device 6, and a light 5 from a crossing point 14 is entered the device 11. Each wavelength of the laser light 4, 4' is different from each other and it is selected so that the sum of energies of both photons is made to be equal to the exciting energy of a specific chemical seed in a plasma apparatus 1. The light emitted from said chemical seed at the point 14 is detected by the detector 11 and its output is inputted to a peak detector 12, and highly accurate distribution of the chemical seed is displayed 13 from its peak value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a plasma monitoring device capable of monitoring the distribution of chemical species in plasma within a plasma utilization device.

2. Description of the Related Art Conventionally, there is a plasma monitor device for a plasma utilization device that detects and monitors plasma emission within the plasma utilization device.

However, this method only detects the total amount of plasma light emission in a certain direction, and it is not possible to grasp the distribution of atoms, etc. that make up the plasma with high precision position resolution.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a plasma monitor device that can measure the distribution of plasma constituent chemical species within a plasma utilization device with high precision position resolution.

In order to achieve the above purpose, the present FlI uses a laser beam with a photon energy larger than half of the excitation energy of a specific chemical species contained in the plasma, and a laser beam with a photon energy smaller than half the excitation energy of the chemical species. It is characterized in that the light is irradiated so as to intersect with the light from substantially perpendicular directions, and the light of the chemical species emitted at the intersection is detected.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a block diagram of the embodiment, and FIG. 2 is an explanatory diagram of laser beam intersection.

1 is a plasma utilization device to be measured; 2.2';

2# is an optical window used for measuring laser light introduction and emission, s
, s' is a continuous wave laser, 4.4' is the laser beam emitted from the laser, 5 is the light emitted by the chemical species excited at the intersection of the laser beams 4.4', and 6 is the laser beam 4'. A laser beam scanning device for scanning up and down, 7 is an optical bench, 8.8', 8' is a movement motor for moving the optical bench 7 up and down, left and right, 0 front and back, 9.9' is a shaft, 1
0 is the moving motor 8.8'.

8' and a control device for controlling the laser beam scanning device 6, 11 a light emission detection device for measuring the light emission 5 generated by the laser f4.4', and 12 detecting the peak of the signal from the light emission detection device. , a peak detection device for holding the peak value, and 13 a display device. FIG. 2 is an explanatory view of scanning, where 14 is an intersection of laser beams 4 and 4', and 15 is a scan plane on which laser beam 4' is scanned by laser beam scanning device 6.

laser! 5.5', the laser beam scanning device 6/light emission detection device 11 is such that the laser beam 4 and the laser beam 4' exiting from the laser beam scanning device 6 are almost perpendicular to each other, and the light emission 5 from the intersection 14 is detected by the light emission detection device. 11 and is fixed to the optical bench 7. The laser beam scanning device 7 is arranged so that the laser beam 4' scans an area including the intersection 14 in a plane 15 substantially perpendicular to the laser beam 4, as shown in FIG.

As a result, the narrow diameter laser beams 4.4' always intersect,
Light emission 5 is generated by the laser beam and is converted into an electrical signal by the light emission detection device 11. The strength of the electrical signal is laser light 4
Since the maximum value is reached when 4' and 4' completely intersect at the intersection 14, a peak detection device 12 is provided to detect and hold this maximum value. The results are displayed on the display device 13.

In the above embodiment, the wavelengths of the laser beams 4.4' used are different from each other, and are selected so that the sum of the energies of both photons is equal to the excitation energy of the chemical species to be measured.

This monitor was applied to aluminum dry etching equipment.

Assuming that the wavelength of the laser light is 769.2 nm and 9454 m,
[It was possible to measure the distribution of A1 atoms in an arbitrary region with a sensitivity of IP9 and a positional resolution of 11-.

According to the present invention, it has become possible to measure the distribution of chemical species in a trace amount of plasma in an arbitrary region while having a highly accurate position resolution of approximately α1■.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a plasma monitor according to the present invention, and FIG. 2 is an explanatory diagram of laser beam intersection. 3.5'・・・・・・・・・1.・Laser 6...
・・・・・・・・・・・・Laser beam scanning device 7・
・・・・・・・・・・・・・・・・Optical bench 8.8',
8'...Moving motor 9.9'...
・・・・・・Shaft 10・・・・・・・・・・・・・・・
・Control device 11......Light emission detection device 12...Peak detection device 13... ...Display device representative patent attorney Usui 1) Profitability / 1) Busyness

Claims (1)

[Claims] For a plasma utilization apparatus having a plurality of optical windows formed on a side wall, an optical bench is arranged to be movable in three dimensions, and the optical bench K is arranged to face one of the optical windows,
a first laser oscillator that oscillates a laser beam into the plasma utilization apparatus; a scanning device disposed on the optical bench so as to face the other one of the optical windows; A second laser beam disposed to face the scanning device and oscillating a laser beam into the plasma utilization device from a direction substantially perpendicular to the laser oscillator through the scanning device.
and a laser oscillator arranged on the optical bench so as to face another one of the optical windows, and detecting light emitted at the intersection of the laser beams oscillated from the first and second laser oscillators. A plasma monitor device comprising a detection device and a display device connected to the detection device and displaying detection results.