Cleaning and liquid contact with solids – Apparatus – Automatic controls
Reexamination Certificate
2001-02-16
2001-09-25
El-Arini, Zeinab (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
Automatic controls
C134S100100
Reexamination Certificate
active
06293288
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a cleaning method and a cleaning apparatus wherein an object to be processed, such as a semiconductor wafer or a glass substrate for an LCD, is immersed in a cleaning liquid and a rinse liquid and cleaned.
2. Description of Related Art
A cleaning method that is widely used during the process of manufacturing semiconductor devices generally involves immersing objects to be processed, such as semiconductor wafers or glass substrates for LCDs (hereinafter called “wafers”), sequentially into a series of cleaning tanks, each filled with a chemical (processing liquid) such as ammonia water (NH
4
OH) or hydrofluoric acid (HF) or a rinse liquid such as distilled water or ozone water, to clean them.
A so-called one-path type of apparatus is known in the art as one form of this cleaning apparatus, wherein a rinse liquid (such as distilled water or ozone water) and a dilute liquid (for example, diluted hydrofluoric acid (DHF) including a rinse liquid and a chemical) such as hydrofluoric acid (HF) are supplied in turn in the same processing tank, and a wafer or the like is immersed within this rinse liquid and diluted liquid for a predetermined time to clean it. With this cleaning apparatus, a dilute liquid (such as DHF) comprising a predetermined quantity of a chemical mixed into a rinse liquid is poured into the processing tank and the wafer or the like is immersed in this dilute liquid (DHF), or the dilute liquid is supplied into the processing tank after the wafer or the like has been accommodated therein, whereby an etching type of “cleaning” can be performed to remove particles adhering to the surfaces of the wafer or to remove metals such as Ni and Fe or natural oxide films that have adhered physically or chemically thereto. The wafer is subsequently immersed in rinse liquid that is supplied to the processing tank, so that any chemical adhering to the wafer surfaces can be removed.
In this prior-art type of cleaning apparatus, the time during which the wafer or the like is immersed and processed in the cleaning liquid is constant, so that if the temperature of the cleaning liquid within the processing tank changes, the wafer processing capability thereof will also change. With cleaning (etching) by DHF, for example, a problem occurs in that the etching characteristics will change, so that the cleaning capability and the cleaning precision thereof will deteriorate.
The present invention was devised in the light of the above situation and has as an object thereof the provision of a cleaning method and apparatus wherein control of processing time is based on the temperature of the cleaning liquid, thereby enabling improvements in cleaning capability and cleaning precision.
SUMMARY OF THE INVENTION
In order to achieve the above object, the present invention provides a cleaning method for immersing an object to be processed into a cleaning liquid within a processing tank and cleaning the object therein, wherein this cleaning method comprises the steps of: detecting the temperature of the cleaning liquid in which the object to be processed is immersed or to be immersed, and generating a corresponding temperature signal; determining an immersion time for the immersion of the object in the cleaning liquid, based on the temperature signal; and immersing the object to be processed in the cleaning liquid, for the immersion time.
The present invention also provides a cleaning method for immersing an object to be processed into a cleaning liquid within a processing tank and cleaning the object therein, this cleaning method being such as to comprise a chemical supply timeband during which a chemical is supplied into the processing tank to gradually increase the concentration of the chemical in the cleaning liquid and an immediately subsequent stabilized concentration timeband; wherein the cleaning method comprises the steps of: detecting the temperature of the cleaning liquid in which the object is immersed or to be immersed, and generating a corresponding temperature signal; rectifying the length of the chemical supply timeband, based on the temperature signal; and immersing the object to be processed in the cleaning liquid, for an immersion time that comprises the rectified chemical supply timeband length.
The present invention further provides a cleaning method for immersing an object to be processed into a cleaning liquid within a processing tank and cleaning the object therein, this cleaning method being such as to comprise a chemical supply timeband during which a chemical is injected into the processing tank to gradually increase the concentration of the chemical in the cleaning liquid and an immediately subsequent stabilized concentration timeband; wherein the cleaning method comprises the steps of: detecting the temperature of the cleaning liquid in which the object is immersed or to be immersed, and generating a corresponding temperature signal; rectifying the length of the stabilized concentration timeband, based on the temperature signal; and immersing the object to be processed in the cleaning liquid, for an immersion time that comprises the rectified stabilized concentration timeband length.
Even further, the present invention provides a cleaning method for immersing an object to be processed into a cleaning liquid within a processing tank and cleaning the object to be processed therein, this cleaning method being such as to comprise a chemical supply timeband during which a chemical is supplied into the processing tank to gradually increase the concentration of the chemical in the cleaning liquid and an immediately subsequent stabilized concentration timeband; wherein the cleaning method comprises the steps of: detecting the temperature of the cleaning liquid in which the object to be processed is immersed or to be immersed, and generating a corresponding temperature signal; pre-determining a rectification time in accordance with the concentration ratio of a processing liquid, for each of a temperature that is greater than a reference temperature for the processing liquid and a temperature that is less than the reference temperature; rectifying the length of the chemical supply timeband by subtracting the rectification time from a reference time for a temperature given by the temperature signal that is greater than the reference temperature, or adding the rectification time to the reference time for a temperature given by the temperature signal that is less than the reference temperature; pre-determining a rectification coefficient in accordance with the concentration ratio of the processing liquid, for each temperature of the processing liquid; rectifying the length of the stabilized concentration timeband by multiplying a reference time for the stabilized concentration timeband by a rectification coefficient corresponding to the temperature given by the temperature signal; and immersing the object in the cleaning liquid, for an immersion time that comprises the rectified chemical supply timeband length and the rectified stabilized concentration timeband length.
Furthermore, the present invention provides a cleaning method for immersing an object to be processed into a cleaning liquid within a processing tank and cleaning the object to be processed therein, wherein this cleaning method comprises the steps of: detecting the temperature of the cleaning liquid in which the object is immersed or to be immersed, and generating a corresponding temperature signal; pre-determining a rectification coefficient in accordance with the concentration ratio of a processing liquid, for each of a temperature that is greater than a reference temperature for the processing liquid and a temperature that is less than the reference temperature; determining the value of a rectification, coefficient, based on the value of the temperature signal; rectifying by multiplying an immersion time for the immersion of the object in the cleaning liquid by the value of the rectification coefficient based on the value of the temperatur
Hyakutake Hironobu
Kitahara Shigenori
Shindo Naoki
El-Arini Zeinab
Smith , Gambrell & Russell, LLP
Tokyo Electron Limited
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