Semiconductor device manufacturing: process – Chemical etching – Vapor phase etching
Reexamination Certificate
2001-08-09
2003-02-04
Whitehead, Jr., Carl (Department: 2813)
Semiconductor device manufacturing: process
Chemical etching
Vapor phase etching
C438S716000, C438S509000, C438S522000, C438S530000
Reexamination Certificate
active
06514869
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a semiconductor device manufacturing method and apparatus; and, more particularly, to a method for manufacturing a semiconductor device employing, e.g., a cold-wall type single wafer chemical vapor deposition (CVD) apparatus.
DESCRIPTION OF THE PRIOR ART
FIG. 5
shows a cross sectional view of a conventional cold-wall type single wafer chemical vapor deposition (CVD) apparatus
500
. As shown in
FIG. 5
, the apparatus
500
includes an exhaust port
2
prepared on a main body
1
, a shower head
3
prepared at an upper part of the main body
1
and a gas inlet
4
installed in the main body
1
, the gas inlet
4
being located above the shower head
3
. The apparatus
500
further includes a heater unit
13
, which is comprised of a support member
5
vertically movable in the main body
1
, a base
6
mounted on the support member
5
, a heater
7
installed on the base
6
through heater electrodes
8
and a susceptor
9
positioned above the heater
7
and mounted on the support member
5
. A silicon wafer
10
mounted on the susceptor
9
and a cover plate
11
is mounted on the support member
5
. A transfer mechanism (not shown) to move the heater unit
13
is also installed in the apparatus
500
. Further, a reaction chamber
12
to process the silicon wafer
10
is provided in the apparatus
500
. In
FIG. 5
, the reference numeral
15
represents a substrate loading/unloading port
15
through which the silicon wafer
10
is loaded and unloaded into and from the reaction chamber
12
.
Hereinafter, there will be described a method for depositing a ruthenium film or ruthenium oxide film on a silicon wafer by employing the cold-wall type single wafer CVD apparatus
500
shown in FIG.
5
.
First, the heater unit
13
is kept at a substrate loading/unloading position or a substrate processing position while the silicon wafer
10
is not mounted on the susceptor
9
. Under this condition, nitrogen gas is supplied into the reaction chamber
12
to thereby perform a purge operation thereof and an electric power is supplied to the heater
7
to thereby stabilize the inner temperature of the apparatus
500
. The process described above is referred to as a pretreatment stage of a continuous substrate processing stage.
Next, the silicon wafer
10
is loaded on the susceptor
9
through the substrate loading/unloading port
15
. Then, by employing the heater unit transfer mechanism (not shown), the heater unit
13
is moved from the substrate loading/unloading position shown in
FIG. 6
to the substrate processing position shown in FIG.
5
. Further, the silicon wafer
10
is heated by the heater
7
to a processing temperature ranging from about 290° C. to about 350° C.
Thereafter, a nitrogen gas is fed into the reaction chamber
12
to thereby set the inner pressure of the reaction chamber
12
at an optimum processing pressure. In a subsequent step, a ruthenium containing source gas and an oxygen containing gas are supplied to a space above the shower head
3
through the gas inlet
4
. The source gas and the oxygen containing gas are simultaneously showered down onto the silicon wafer
10
through the shower head
3
and ruthenium in the source gas is deposited on the silicon wafer
10
through the reaction with oxygen in the oxygen containing gas, thereby forming a ruthenium film or ruthenium oxide film on the silicon wafer
10
.
Next, the supply of the source gas and the oxygen containing gas is stopped and a purge operation is performed in the reaction chamber
12
by supplying nitrogen gas to remove the remaining gases. Then, the processed silicon wafer
10
is lowered by transferring the heater unit
13
from the substrate processing position to the substrate loading/unloading position by the heater unit transfer mechanism, and unloaded from the apparatus
500
through the substrate loading/unloading port
15
.
A new silicon wafer
10
is then mounted on the susceptor
9
and the deposition process of the ruthenium film or the ruthenium oxide film on the new silicon wafer
10
is performed in a same manner as described above. The above process is continuously repeated to process a set of silicon wafers, thus completing one continuous substrate processing stage.
After one continuous substrate processing stage is completed, the pretreatment stage is carried out prior to starting a subsequent continuous substrate processing stage for another set of silicon wafers. During the pretreatment stage as described above, the heater unit
13
without the silicon wafer
10
loaded on the susceptor
9
is kept at either the substrate loading/unloading position or the substrate processing position; and a purge operation is performed by supplying nitrogen gas into the reaction chamber
12
and an electric power is supplied to the heater
7
to thereby stabilize a temperature condition of the apparatus
500
.
The conventional pretreatment stage described above has certain drawbacks in that it may be subjected to large temporal temperature variations at the shower head
3
. Specifically, when the pretreatment stage is carried out while maintaining the heater unit
13
at the substrate loading/unloading position, the temperature of the shower head
3
at the onset of the subsequent continuous substrate processing stage becomes considerably lower than that after being stabilized during the continuous substrate processing stage.
On the other hand, in case when the heater unit
13
is kept at the substrate processing position until the subsequent continuous substrate processing stage starts, the temperature of the shower head
3
at the beginning of the continuous substrate processing stage becomes a lot higher than that after being stabilized during the continuous substrate processing stage. Accordingly, since the temperature of the shower head
3
during the continuous substrate processing stage can vary greatly as described above, it may be difficult to form a ruthenium film or a ruthenium oxide film having a uniform thickness and a uniform film quality.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method and apparatus capable of continuously processing a set of substrates while temporally reducing ambient temperature variations around the substrates.
In accordance with one aspect of the invention, there is provided a semiconductor device manufacturing method for processing a plurality of substrates by alternately repeating a pretreatment stage and a continuous substrate processing stage, wherein the continuous substrate processing stage comprises the steps of: loading a substrate on a heater unit located at a substrate loading/unloading position, the heater unit supporting and heating the substrate; processing the loaded substrate by transferring the heater unit having thereon the loaded substrate to a substrate processing position; unloading the processed substrate; and repeating the loading step, the processing step and the unloading step until a set of substrates are processed, and wherein the pretreatment stage is carried out by maintaining the heater unit between the substrate loading/unloading position and the substrate processing position.
In accordance with another aspect of the invention, there is provided a semiconductor device manufacturing apparatus comprising: a reaction chamber to process substrates; a heater unit to support and heat the substrates; and a shower head for feeding a process gas to the substrates in a spray form, wherein the substrates are processed according to the above-mentioned method.
In accordance with still another aspect of the invention, there is provided a semiconductor device manufacturing method for processing a plurality of substrates by alternately repeating a pretreatment stage and a continuous substrate processing stage, wherein the continuous substrate processing stage comprises the steps of: loading a substrate on a heater unit located at a substrate loading/unloading position, the heater unit supporting and heating the substrate; processing
Miyata Toshimitsu
Nishitani Eisuke
Wada Tetsuya
Bacon & Thomas
Hitachi Kokusai Electric Inc.
Jr. Carl Whitehead
Thompson Craig
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