Cleaning and liquid contact with solids – Processes – Including application of electrical radiant or wave energy...
Reexamination Certificate
2000-08-18
2003-03-04
Gulakowski, Randy (Department: 1746)
Cleaning and liquid contact with solids
Processes
Including application of electrical radiant or wave energy...
C134S021000, C134S025400, C134S026000, C134S030000, C134S037000, C134S902000, C438S906000, C015S001510
Reexamination Certificate
active
06526997
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to techniques for cleaning objects. More particularly, the invention provides a technique including a method for cleaning semiconductor devices using a combination of a high energy light source and electrostatic bias for removing impurities, such as particles and the like from integrated circuits, for example. But it will be recognized that the invention has a wider range of applicability; it can also be applied to other devices such as three-dimensional packaging of integrated semiconductor devices, photonic devices, opto-electronic devices, piezoelectronic devices, microelectromechanical systems (“MEMS”), sensors, actuators, solar cells, flat panel displays (e.g., LCD, AMLCD), biological and biomedical devices, and the like.
As integrated circuit device sizes become smaller, it is more desirable to remove particulate contamination from surfaces of such devices. Many techniques have been proposed or used to remove such particulate contamination. In the early days, such techniques have been limited to wet processing methods. These wet processing methods include a cascade rinse. The cascade rinse often utilizes a cascade rinser which includes inner and outer chambers, each separated by a partition. Rinse water flows from a water source into the inner chamber. The rinse water from the inner chamber cascades into the outer chamber. An in-process wafer such as an etched wafer is typically rinsed in the cascade rinser by dipping the etched wafer into the rinse water of the inner chamber. This process is often used to neutralize and remove acid from the etched wafer, which often remains in the rinse chamber to create particulate contamination problems.
Another technique often used to rinse wafers is the “quick dump” method. The quick dump method relies upon the rapid deployment of water from the rinse tank to remove water and impurities from the semiconductor wafer. A limitation with this method is its inability to actually clean or remove particles from the wafer. In fact, the rapid deployment of water from the tank often transfers more particles onto the wafer. In addition, the wafers from the quick dump tank must still undergo a drying operation, further increasing the number of particles on the wafer. As previously noted, more particles often relates to lower die yields on the semiconductor wafer.
A further technique used to both rinse and dry wafers relies upon a spin rinse/dryer. The spin rinse/dryer uses a combination of rinse water spray to rinse and centrifugal force to remove water from the semiconductor wafer. The dry step often removes the water from the semiconductor wafer substantially by centrifugal force and evaporation. However, the spin rinse/dryer often introduces more particles onto the wafer. In fact, initially dissolved or suspended contaminants such as particles in the water are often left on the semiconductor wafer, thereby reducing the number of good dies on the wafer. Another limitation with the spin rinse/dryer is its complex mechanical design with moving parts and the like. The complex mechanical design often leads to certain problems such as greater downtime, wafer breakage, more spare parts, greater costs, among others. A further limitation is static electricity often builds up on the wafers during the spin cycle, thereby attracting even more particles onto the surface of the semiconductor. Accordingly, the spin rinse/drying does not clean or remove particles from the wafer.
Other techniques used to dry wafers include an isopropyl alcohol (IPA) vapor dryer, full displacement IPA dryer, and others. These IPA-type dryers often rely upon a large quantity of a solvent such as isopropyl alcohol and other volatile organic liquids to facilitate drying of the semiconductor wafer. A limitation with this type of dryer is its use of the large solvent quantity, which is hot, highly flammable, and extremely hazardous to health and the environment.
Several dry techniques have also been used. For example, silicon wafers have been cleaned using an argon
itrogen cryogenic aerosol process. Such dry technique has had many promising characteristics, but has had limited use in the manufacture of integrated circuits so far. Other techniques that have been proposed but still lack wide acceptance in the manufacture of integrated circuits. Such techniques often require the use of expensive equipment, chemicals, and the like. Additionally, such techniques have proved not to be significantly effective for cleaning silicon wafers.
From the above, it is seen that an improved method for cleaning objects is highly desirable.
SUMMARY OF THE INVENTION
According to the present invention, a technique including a method for manufacturing objects is provided. More particularly, the invention provides a technique including a method for cleaning objects using a combination of a high energy light source and electrostatic bias for removing impurities, such as particles and the like from integrated circuits, for example. But it will be recognized that the invention has a wider range of applicability; it can also be applied to other devices such as three-dimensional packaging of integrated semiconductor devices, photonic devices, opto-electronic devices, piezoelectronic devices, microelectromechanical systems (“MEMS”), sensors, actuators, solar cells, flat panel displays (e.g., LCD, AMLCD), biological and biomedical devices, and the like.
In a specific embodiment, the invention provides a method for manufacturing an integrated circuit device. The method includes retrieving an in process substrate comprising one or more particles from an input chamber, which is coupled to a chamber for a robot arm, which is maintained under a predetermined environment. The method moves the substrate from the input chamber into a cleaning chamber, which is coupled to the robot arm chamber. The method places the substrate onto a susceptor in the cleaning chamber; and applies a high energy photon from a high energy photon source onto a surface of a substrate to release the one or more particles from the surface of the substrate while the substrate is maintained in the predetermined environment. The method also applies an electrostatic force from an electrode directed to the substrate to attract the released one or more particles from the substrate to remove the one or more particles from the surface of the substrate, where upon the electrostatic force prevents a possibility of the one or more particles from redistributing back onto the surface of the substrate.
Numerous benefits are achieved over pre-existing techniques using the present invention. In a specific embodiment, the invention provides a clean and dry cleaning process, which is free from harmful chemicals, gases, and the like. In other embodiments, the invention permanently removes particles, which cannot reattach themselves to the substrate. The invention can be implemented using conventional hardware and software, with some customization. The method can be applied to the manufacture of many types of objects, e.g., integrated circuits, disks, opto-electronic devices. In other aspects, the invention is also cluster tool compatible, which can be used with other processes. The invention can also be applied after a variety of integrated circuit device manufacturing processes, e.g., etching, pre-gate oxide formation, deposition, plating. The invention also provides a non-contact, dry, technique for removing a particle. In other aspects, the invention also prevents particles from reattaching onto surfaces of the object being processed. The invention is also clustertool compatible. Depending upon the application, one or more of these advantages may exist, but do not need to all exist to carry out the claims herein.
REFERENCES:
patent: 4744833 (1988-05-01), Cooper et al.
patent: 5024968 (1991-06-01), Engelsberg
patent: 5099557 (1992-03-01), Engelsberg
patent: 5125124 (1992-06-01), Saeki et al.
patent: 5228206 (1993-07-01), Grant et al.
patent: 5584938 (1996-12-01), Douglas
patent: 5858108 (1999-01-01)
Gulakowski Randy
Kornakov M.
Townsend and Townsend and Crew
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