Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
2000-02-02
2001-09-04
Mills, Gregory (Department: 1763)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S710000, C216S038000
Reexamination Certificate
active
06284668
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plasma polishing apparatus and a plasma polishing method in a semiconductor process and, more particularly to, a dry polishing apparatus and a dry polishing method of polishing a target object by a plasma without using a polishing solution.
2. Description of the Related Art
In manufacturing processes for semiconductor devices and liquid crystal displays, the surfaces of target objects are polished to reduce irregularity on the surfaces of the target objects such as semiconductor wafers and LCD substrates. As representative polishing of this type, a so-called CMP (Chemical Mechanical Polishing) method is known in which the surface of a target object is mechanically polished using a chemical polishing solution, a pad, and so forth.
FIGS. 11 and 12
show an example of a conventional CMP apparatus. This CMP apparatus comprises a rotary table
104
having a polishing pad
102
arranged on its surface. A wafer holder
106
rotated by a motor
112
(
FIG. 12
) is arranged above the table
104
. A nozzle
108
for supplying the slurry of a chemical polishing solution containing, e.g., silica as a main component is arranged above the surface of the polishing pad
102
.
In polishing, a wafer W as a target object is held by the holder
106
and pressed against the pad
102
at a predetermined pressure. In this state, both the table
104
and the holder
106
are rotated, and a polishing solution i s supplied from the nozzle
108
. In this manner, the surface of the wafer W is polished a friction among the chemical polishing solution, the pad
102
and the surface of the wafer W.
Since the above-described CMP apparatus, however, polishes the wafer in a wet atmosphere by using a chemical polishing solution, it requires a scattering prevention mechanism for a polishing solution and a recovery mechanism for a waste solution. In addition, this CMP apparatus must perform the post-process step of cleaning a wafer after it is polished.
Since the polishing pad is pressed against the surface of a wafer in the above-described CMP apparatus, a progress of polishing the wafer surface cannot be directly observed. It is therefore difficult to detect the end of polishing. Further, this CMP apparatus uses many control parameters such as the pressure, the rotational speeds of the rotary table and the wafer holder, the supply amount of a polishing solution, and the polishing time, so that a wealth of experiences and know-how are required to perform optimum polishing.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a new polishing apparatus and method capable of polishing a target object in a dry atmosphere at substantially the atmospheric pressure using no polishing solution.
According to a first aspect of the present invention, there is provided a plasma polishing apparatus for polishing a surface of a target object, comprising:
a plasma generator for converting a process gas into a plasma, the plasma generator having an outlet port from which the plasma flows out, the outlet port being substantially smaller than the surface;
a table for holding the target object so as to position the surface of the target object opposite to the outlet port; and
a rotary driver for rotating the table together with the target object at a high speed, such that the plasma is drawn and diffused in a laminar flow state on the surface of the target object by a centrifugal force generated upon rotation of the surface, and polishes the surface during diffusion on the surface.
According to a second aspect of the present invention, there is provided a plasma polishing method of polishing a surface of a target object, comprising the steps of:
holding the target object by a table so as to expose the surface of the target object;
converting a process gas into a plasma and supplying the plasma onto the surface from an outlet port substantially smaller than the surface of the target object; and
rotating the table together with the target object at a high speed, such that the plasma is drawn and diffused in a laminar flow state on the surface of the target object by a centrifugal force generated upon rotation of the surface, and polishes the surface during diffusion on the surface.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
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patent: 5431769 (1995-07-01), Kisakibaru et al.
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patent: 5628829 (1997-05-01), Foster et al.
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patent: 6013191 (2000-01-01), Nasser-Faili et al.
Plasma Jet Etching, Technology and Equipment, 4 pages, “Silicon Wafer Thinning & Isotropical Etching Atmospheric Pressure” No Date Available.
Alejandro Luz L.
Mills Gregory
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Tokyo Electron Limited
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