Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
1999-07-06
2001-07-03
Utech, Benjamin L. (Department: 1765)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S710000
Reexamination Certificate
active
06255220
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method for plasma control and an apparatus for plasma control used in plasma CVD, plasma RIE, and spattering.
2. Description of the Related Art
Plasma processing is categorized to various technologies such as plasma CVD, plasma RIE, spattering and ion plating, but any way in the all these technologies an object to be processed is placed in a processing chamber and a type of plasma is generated, thus the object is subjected to film forming or etching by the action of ion or electron.
FIGS. 1A and 1B
are schematic diagrams for illustrating conventional plasma processing equipments,
FIG. 1A
shows a parallel flat plate type, and
FIG. 1B
shows ECR type equipments.
The parallel flat plate type equipment comprises a processing chamber
1
in which the object
4
to be processed such as wafer is placed, top and bottom electrodes
5
and
6
provided facing each other in the processing chamber
1
, and a DC bias
2
and high frequency bias
3
for applying voltage on the bottom electrode
6
.
For processing using the parallel flat plate type plasma processing equipment, a gas (not shown) is introduced in the processing chamber
1
, and high frequency bias
3
of, for example, 13.56 MHz is applied to generate plasma
7
in a space between the top electrode
5
and the bottom electrode
6
, and thus, for example, a film is formed on the surface of the object
4
.
Plasma
7
in the processing chamber
1
is controlled by electric field perpendicular to the surface of the object
4
and flow of the gas to maintain the plasma density uniform.
The ECR type plasma processing equipment shown in
FIG. 1B
comprises a processing chamber
11
in which the object
10
to be processed is placed, a wave guide
11
a
for feeding microwave into the processing chamber
11
, and coils
12
for generating magnetic field.
For operating the ECR type plasma processing equipment, a gas is introduced into the processing chamber
11
and microwave with a frequency of, for example, 2.45 GHz is fed to cause discharging, and the rotation of electrons which are being rotated by applying magnetic field from the coils
12
resonates with the frequency of microwave to generates high performance plasma
13
.
The plasma
13
in the processing chamber
1
is controlled by prescribed bias and gas flow to process the object
10
.
In any plasma processing equipment for proper processing, ion or electron is controlled to be projected perpendicular to the surface of the object.
Therefore, the quality of processing in the direction perpendicular to the surface of the object, for example, film thickness and etching depth, can be controlled, but the quality in the direction other than perpendicular direction cannot be controlled, and these equipments are not suitable for processing of the object with complex structure.
For example, when a taper is to be provided at a trench and a oxide film with desired thickness is to be formed on the inside surface of the trench on a semiconductor element, a conventional plasma processing equipment cannot control such processing, this disadvantage of the conventional equipment has been a serious problem for processing objects with complex structure.
SUMMARY OF THE INVENTION
It is the first object of the present invention to control the movement of ion or electron in plasma using electric field and magnetic field.
It is the second object of the present invention to provide semiconductor devices processed with ion or electron in plasma under controlled condition.
The present invention provides a method for plasma control for controlling ion or electron in plasma atmosphere in a processing chamber in which the object to be processed is placed, electric fields are generated in the directions not only perpendicular to the surface of the object but also parallel to the surface of the object, and the direction of ion or electron in plasma is controlled based on the composite electric field.
The present invention provides a method for plasma control as described in the above mentioned inventions, in which the electric field in the parallel direction to the surface of the object is generated by inverting the direction of magnetic field generated in the parallel direction to the surface periodically.
The present invention provides a method for plasma control for controlling the direction of ion or electron in plasma atmosphere generated in a processing chamber in which the object to be processed is placed, in which electric field is generated in the perpendicular direction to the surface of the object and another electric field generated in the direction parallel to the surface of the object is rotated by rotating a magnetic field which is generated in the direction parallel to the surface around an axis perpendicular to the surface to control ion or electron in the plasma atmosphere based on the composite electric field composed of both directions.
The present invention provides a method for plasma control as described in the above mentioned inventions, in which ion or electron in plasma atmosphere is controlled by adjusting gas pressure introduced in the processing chamber.
The present invention provides a method for plasma control as described in the above mentioned inventions, in which the electric field generated in the direction parallel to the surface of the object in the processing chamber is controlled based on reactance and conductivity of the electrode on which the object is to be placed in the processing chamber.
The present invention provides a method for plasma control as described in the above mentioned inventions, in which the magnetic flux density around the surface of the object is controlled based on the moving period of the magnetic field generated in the direction parallel to the surface of the object.
The present invention provides a method for plasma control in accordance with the above mentioned inventions, in which the invention is applied when plasma is used for plasma CVD, plasma is used for plasma RIE, plasma is used for spattering, and plasma is used for ion-plating.
The present invention provides a method for plasma control as described in the above mentioned invention, wherein the invention is applied when plasma is used for flattening of the object and plasma is used for polishing of the object.
The present invention provides an apparatus for plasma control for controlling ion or electron in plasma atmosphere generated in a processing chamber in which the object to be processed is placed, provided with a perpendicular electric field generating means for generating an electric field in the direction perpendicular to the surface of the object and a parallel electric field generating means for generating an electric field in the direction parallel to the surface of the object.
The present invention provides an apparatus for plasma control as described in the above mentioned invention, in which the parallel electric field generating means comprises a pair of coils provided facing each other outside the processing chamber with interposition of the object and an power supply means for feeding an AC current with a certain period to the pair of coils.
The present invention provides an apparatus for plasma control for controlling ion or electron in plasma atmosphere generated in a processing chamber in which the object to be processed is placed, provided with a perpendicular electric field generating means for generating an electric field in the direction perpendicular to the surface of the object and a rotating magnetic field generating means for rotating a magnetic field generated in the direction parallel to the surface of the object.
The present invention provides an apparatus for plasma control as described in the above mentioned invention, in which the rotating magnetic field generating means comprises a coil wound around the object and a polyphase power supply for feeding a current to the coil.
The present invention provides an apparatus for plasma control, in which the rotating
Bannai Satoshi
Chiba Tomohiro
Honbori Isao
Kato Yasushi
Kawashima Toshitaka
Deo Duy-Vu
Sonnenschein Nath & Rosenthal
Sony Corporation
Utech Benjamin L.
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