Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – With microwave gas energizing means
Reexamination Certificate
2000-02-16
2001-07-17
Bueker, Richard (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
With microwave gas energizing means
C118S715000, C118S7230ER
Reexamination Certificate
active
06261408
ABSTRACT:
BACKGROUND OF THE DISCLOSURE
1. Field of Invention
The present invention relates generally to a semiconductor substrate processing apparatus. More specifically, the invention relates to an apparatus and method for providing pressure control within a semiconductor processing chamber.
2. Background of the Invention
In plasma processing of semiconductor substrates, certain processing steps require the regulation of chamber pressures and removal of gases and process residues from a processing chamber. Typically, pressure regulation and the removal of such gases and process residues are facilitated through the use of a vacuum pump and throttle valve coupled to an exhaust port of the processing chamber.
FIG. 1
depicts an exemplary semiconductor substrate processing system
10
having a throttle valve
38
and vacuum pump
40
. An example of such a chamber is described by Collins in U.S. Pat. No. 5,707,486, issued Jan. 13, 1998.
The processing system
10
comprises a process chamber
44
having a bottom
26
, sidewalls
24
, and a lid
22
that define a chamber volume
12
. A substrate support pedestal
18
is disposed in the process chamber
44
and supports a workpiece or substrate
20
(i.e., a wafer). Generally, a gas supply
42
is coupled to the process chamber
44
via one or more ports positioned either in the lid
22
or sidewalls
24
. The gas supply
42
provides process and other gases to a processing region
14
above the substrate
20
.
The chamber volume
12
is evacuated via the vacuum pump
40
coupled to the process chamber
44
typically through an exhaust port
36
positioned below the level of the substrate
20
. The throttle valve
38
is coupled disposed between the process chamber
44
and the vacuum pump
40
. A pressure control volume
46
is defined as the internal volume of the process chamber
44
upstream of the throttle valve
38
. Generally, on typical systems, the chamber volume
12
and the pressure control volume
46
are substantially identical. Pressure is regulated within the process chamber
44
by actuating the throttle valve
38
. Changes to the chamber pressure effectuated by the throttle valve
38
are propagated through the entire pressure control volume
46
.
Although pressure control using the system described above has proven to be robust, the large size of the pressure control volume delays changes in chamber pressure in response to pressure control measures (i.e., such as throttle valve actuation). Additionally, since the pressure control volume is substantially equal to the chamber volume, the resonance time of gases within the chamber is long. Long resonance times of etchants result in other components within the chamber having to be replaced frequently (i.e., high cost of consumables) while long resonance times of reaction by-products may contribute to chamber and wafer contamination. Moreover, large volumes generally require more gases to obtain desired process concentrations, longer purge times, and greater processing cost.
Therefore, there is a need for an apparatus that facilitates pressure control in a semiconductor processing chamber while reducing the volume of the pressure control region.
SUMMARY OF THE INVENTION
Generally, the present invention provides a processing chamber comprising a pressure control ring and a throttling ridge. The pressure control ring is movably disposed proximate the throttling ridge to define an adjustable flow control orifice. The pressure control ring is connected to a ring actuator. The position of the control ring is controlled via a controller. The controller, in response to a process routine and a signal indicative of chamber pressure, causes the ring actuator to move the pressure control ring, consequently varying the area of the control orifice, and thus maintaining the chamber pressure at a predetermined value.
A method for controlling processing chamber pressure is also disclosed. Generally, the inventive method comprises the steps of sensing a pressure within a processing chamber; translating a ring within the processing chamber in response to the sensed pressure, the translation increasing or decreasing a flow restriction past the ring, the change in flow having a corresponding change in chamber pressure; and repeating the sensing and translating steps to maintain the sensed pressure substantially equal to a predetermined pressure value.
REFERENCES:
patent: 5707486 (1998-01-01), Collins
Nguyen Andrew
Schneider Gerhard
Applied Materials Inc.
Bueker Richard
Thomason Moser & Patterson
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