Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With measuring – sensing – detection or process control means
Reexamination Certificate
2001-02-26
2004-03-30
Hassanzadeh, Parviz (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With measuring, sensing, detection or process control means
C156S345250, C118S715000, C118S712000
Reexamination Certificate
active
06712928
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and device for detecting fine particles (contaminants) suspended in a processing chamber of a processing device for semiconductor devices for forming desired films, circuit patterns, and the like on a semiconductor substrate using plasma through etching, sputtering, CVD, or the like. The present invention also relates to a device for processing semiconductor devices equipped with a function for measuring, in real time during processing, particles generated in the processing chamber when films, circuit patterns, and the like are being formed with a plasma processing technology.
Processes using plasma are widely used in semiconductor device processing (production) processes and liquid crystal display device substrate processing (production) processes, e.g., in etching devices.
FIG. 25
shows an example of a processing device that uses plasma in the form of a parallel flat plasma etching device. As shown in
FIG. 25
, this type of device uses a high-frequency signal from a signal generator
83
to modulate the output potential from a power amp
84
. This high-frequency potential is split up using a distributor
85
applied to an upper electrode
81
and a lower electrode
82
disposed parallel to each other in a processing chamber
86
. Discharge between the two electrodes
81
,
82
generates a plasma
71
from an etching gas. Etching is performed on the workpiece, e.g., a semiconductor substrate (wafer) W.
The high-frequency signal is a signal with a frequency of, for example, 400 kHz. In the etching operation, the progress of etching is monitored and the timing at which to stop etching is detected as accurately as possible so that etching is performed for a predetermined pattern and depth. When the stopping timing is detected, the output from the power amp
84
is stopped and the semiconductor wafer W is ejected from the plasma processing chamber
86
.
In this plasma etching device, it is known that the etching reaction product from the plasma operation is deposited on the wall surface of the plasma processing chamber or the electrodes. As time goes by, the product peels off and forms suspended fine particles. As soon as the etching operation is completed and the plasma discharge stops, these suspended fine particles drop onto the wafer to form adhesed particles, leading to negative circuit properties and visual pattern defects. Ultimately, these can lead to reduced yield and reduced reliability of the elements.
Many types of devices for inspecting particles adhered to the surface of the wafer have been proposed and implemented, but these remove the wafer from the plasma processing device to perform inspection. By the time it is known that many particles are present, the processing of another wafer is already begun. This leads to clusters of defects and reduced yield. Also, evaluations performed after processing cannot determine distribution or changes over time in particles inside the processing.
Thus, there is a need in the field of semiconductor fabrication, liquid crystal fabrication, and the like of a technology for performing in-situ real-time monitoring of contamination status in processing chambers.
The sizes of fine particles suspended in the processing chamber range from submicrons to several hundred microns. In the semiconductor field, where integration scale is growing to include 256 Mbit DRAMs (Dynamic Random Access Memory) and 1 Gbit DRAMs, the minimum circuit pattern widths is decreasing to 0.25-0.18 microns. Thus, there is a need to detect sizes of particles down to the order of submicrons.
Conventional technologies for monitoring fine particles suspended in processing chambers (vacuum processing chambers) such as plasma processing chambers include Japanese laid-open patent publication number 57-118630 (background technology 1), Japanese laid-open patent publication number 3-25355 (background technology 2), Japanese laid-open patent publication number 3-147317 (background technology 3), Japanese laid-open patent publication number 6-82358 (background technology 4), Japanese laid-open patent publication number 6-124902 (background technology 5), and Japanese laid-open patent publication number Hei 10-213539 (background technology 6).
The background technology 1 discloses a vaporization device equipped with: means for illuminating a reaction space with a parallel light having a spectrum different from the spectrum of self-emitted light of the reaction space; and means for receiving parallel light illumination and detecting light scattered by fine particles generated in the reaction space.
The background technology 2 discloses a device for measuring fine particles that uses scattering of laser light to measure fine particles adhesed to a semiconductor device substrate surface and suspended fine particles. The device for measuring fine particles is equipped with a laser light phase modulator generating two laser lights modulated at predetermined frequencies having identical wavelengths and mutual phase differences; an optical system intersecting the two laser lights in a space containing the fine particles to be measured; an optical detection system receiving light scattered by the fine particles to be measured in the region where the two laser lights intersect and converting the light into an electrical signal; and a signal processor extracting a signal component from the electrical signal generated by the scattered light where the frequency is identical or twice the frequency of a phase modulation signal from the laser light phase modulator and the phase difference with the phase modulation signal is constant in time.
The background technology 3 discloses a technology for measuring contamination status in a reaction container that includes a step for performing scanning illumination with coherent light and generating scattered light in the reaction container and a step for detecting the scattered light in the reaction container. The scattered light is analyzed to measure the contamination status.
The background technology 4 discloses a particle detector equipped with: laser means generating a laser light; scanner means using the laser light to scan a region in a reaction chamber of a plasma processing tool containing particles to be measured; a video camera generating a video signal of laser light scattered by particles in the region; and means for processing and displaying an image from the video signal.
The background technology 5 discloses a plasma processing device equipped with: a camera device observing a plasma generating region in a plasma processing chamber; a data processing module processing an image obtained from the camera device to obtain desired information; and a control module controlling at least one of the following list to reduce particles based on information obtained by the data processing module: evacuating means; process gas introducing means; high-frequency potential applying means; and purge gas introducing means.
The background technology 6 discloses a fine particle sensor including: a light emitter sending out a light beam illuminating a space to be measured; a detector containing an optical detector and an optical system focusing the scattered light from the space to be measured and directing it to the optical detector, the being set up so that the optical detector generates a signal representing the intensity of the light directed toward the optical detector; a pulse detector connected to the optical detector to analyze the signal from the optical detector, and detecting pulses in the signal from the optical detector; and signal processing means containing an event detector detecting a series of pulses resulting from scattered light generated by fine particles accompanying multiple illuminations by the beam while it moves in the measurement space.
In the conventional technologies described above, a laser light is sent in through an observation window disposed on a side surface of a processing device. A different observation window from the laser entry observation
Nakano Hiroyuki
Nakata Toshihiko
Hassanzadeh Parviz
Hitachi , Ltd.
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