Liquid purification or separation – With alarm – indicator – register – recorder – signal or...
Reexamination Certificate
2000-02-03
2001-07-03
Drodge, Joseph W. (Department: 1723)
Liquid purification or separation
With alarm, indicator, register, recorder, signal or...
C210S138000, C210S167050, C210S258000, C417S042000, C417S293000, C451S060000, C451S446000
Reexamination Certificate
active
06254767
ABSTRACT:
This application relies for priority upon Korean Patent Application No. 99-4427, filed on Feb. 9, 1999, the contents of which are herein incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus used to manufacture a semiconductor device, and more particularly, to a semiconductor manufacturing apparatus having a controller detecting function of a filter.
2. Description of the Related Art
Most processes for manufacturing a semiconductor device require the use of chemical solutions. In particular, a chemical and mechanical polishing (CMP) apparatus used to planarize a highly integrated semiconductor device uses a slurry as a polishing agent. Such a slurry generally contains impurities, e.g., clustered impurities, in a predetermined size. These impurities contained in the slurry are then filtered by a filter, and the filtered slurry is used for a real process. However, once a filter has been used for a long period of time, the filtering function of the filter deteriorates. Accordingly, it takes an increased period of time to filter a predetermined amount of slurry.
FIG. 1
is a schematic view of a conventional CMP apparatus. Here, reference a represents a service area where the CMP apparatus is repaired, and reference b represents a clean room area where a real process is performed. Thus, the service area a and the clean room area b are separated and the concentration of particles in the atmosphere is also different in each area.
Referring to
FIG. 1
, within the service area a there is a tank
10
that contains a chemical solution
15
such as slurry, a pump
20
for circulating the chemical solution in the tank
10
, and a filter for filtering impurities in the chemical solution discharged from the pump
20
. Usually, the pump
20
is a diaphragm pump having an air inlet
23
and an air outlet
26
. Also, a main body
30
, i.e., a chemical mechanical polisher, is installed in the clean room area b. An outlet of the filter
35
is connected to the main body
30
to provide a part of the filtered chemical solution, i.e., a part of filtered slurry, to the main body
30
. As the period of time that the filter
35
has been used increases, the filtering function of the filter
35
deteriorates. Also, as the functioning of the filter
35
decreases, the operating cycle of the pump
20
becomes longer. Also, in the worst case, the filter
35
may become clogged, so that the process in the main body
30
, i.e., the CMP process, cannot be performed.
In the above-described conventional CMP apparatus, an operator must periodically check the operating cycle of the filter
35
installed in the service area and must take the time to replace the filter when necessary. However, visual and aural checking of the operating cycle of the pump
20
can be inaccurate. Thus, a set maximum safe period of use for a filter
35
is predetermined, and when the actual period of time for which the filter
35
has been used reaches this set maximum safe usable period, the filter
35
should be replaced. However, all filters have different life spans, and so it is difficult to differentiate the maximum actual usable period for each filter. Thus, it is difficult to efficiently use the filter and to prevent problems caused by the clogging of the filter or the discarding of usable filters.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a semiconductor device manufacturing apparatus capable of accurately detecting whether a filter has deteriorated by changing the operating cycle of a pump that circulates a chemical solution into an electrical pulse signal and then by measuring the cycle of the pulse signal.
It is another object of the present invention to provide a semiconductor device manufacturing apparatus capable of accurately detecting the timing for replacing a filter according to the condition of the filter, thereby preventing abrupt stoppages of a main body during processing.
It is still another object of the present invention to provide a semiconductor device manufacturing apparatus having a controller that automatically detects the level of a chemical solution in a tank, thereby preventing accidents caused by the shortage of a chemical solution in a tank.
According to an aspect of the present invention to achieve these and other objects, there is provided a semiconductor device manufacturing apparatus comprising: a tank for storing a chemical solution; a pump for circulating the chemical solution contained in the tank; a filter interposed between the pump and the inlet of the tank, for filtering impurities from the circulating chemical solution; at least one main body connected to an outlet of the filter, for a predetermined function; a pumping cycle sensor for changing the pumping operation of the pump into an electrical signal, e.g. a pulse signal; and a controller for measuring the cycle time of the pulse signals generated by the pumping cycle sensor to determine the level of deterioration of the filter.
The pump circulates the chemical solution contained in the tank. Preferably, at least one level sensor is installed on the sidewalls of the tank. A signal generated by at least one level sensor is transferred to the controller. The controller then processes the signal transferred from the at least one level sensor to detect the amount of chemical solution contained in the tank. Preferably, the pump is a diaphragm pump having an air inlet and an air outlet. The diaphragm pump releases air with a constant pressure via the air outlet whenever the chemical solution contained in the tank is transferred to the filter. When the chemical solution is a slurry used for chemical mechanical polishing, at least one main body corresponds to a chemical mechanical polisher.
The pumping cycle sensor preferably comprises a switch for supplying a power supply voltage, e.g., a DC power voltage, to the controller whenever a button supported by a spring installed in the body is pressed, and a panel installed between the button and the air outlet of the pump. One end of the panel is connected to the body of the switch by a hinge. Thus, when a predetermined pressure of air is exhausted via the air outlet of the pump, the switch instantaneously turns on to transfer a pulse signal to the controller.
The controller preferably comprises an adaptor for changing an AC power voltage to a DC power voltage, a pumping cycle setting portion for storing the maximum allowable operating period of the pump, a pumping cycle signal generator for generating a toggle signal whose logic state changes whenever a pulse signal is input from the pumping cycle sensor, a pumping cycle measuring portion for measuring the time for which the toggle signal output from the pumping cycle signal generator remains at a first state, a comparator for determining whether the maximum allowable operating period stored in the pumping cycle setting portion is equal to the actual operating cycle of the pump measured by the pumping cycle measuring portion, a first switch interposed between the pumping cycle sensor and the pumping cycle signal generator, a second switch interposed between the pumping cycle signal generator and the pumping cycle measuring portion, an alarm unit for generating an alarm and turning off the first and second switches when the measured pumping cycle is equal to the maximum allowable operating period, to stop the operation of the pumping cycle signal generator and the pumping cycle measuring portion, and a reset switch for initializing the pumping cycle signal generator and the pumping cycle measuring portion.
Preferably, the controller further comprises a multi-vibrator for operating the alarm unit when the pulse signal output via the first switch is longer than a predetermined cycle. More preferably the multi-vibrator is a triggerable multi-vibrator.
According to another aspect of the present invention to achieve these and other objects, there is provided a semiconductor device manufacturing apparatus comprising a plurality
Hah Sang-rok
Shin Sung-ki
Drodge Joseph W.
Jones Volentine PLLC
Samsung Electronics Co,. Ltd.
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