Apparatus for atomic layer deposition
A trap with a residence time at least equal to one complete cycle time of an atomic layer deposition (ALD) process traps the gaseous effluent from a reaction chamber and reaction products before the effluent can enter a backing pump. The trap may be connected directly to the reaction chamber or indirectly through a process pump. The trap is advantageously used in atomic layer deposition processes.
1 . Chemical vapor layer deposition apparatus comprising:
first and second precursor gas sources, first and second valves connected to said first and second precursor gas sources;
a purge gas source, said purge gas source having a third valve, said valve permitting inert gas flow, first and said second precursor gas sources and said purge gas operate sequentially to define a deposition cycle,
a reaction chamber, said reaction chamber being connected to said first, said second, and said third valves;
a trap connected to said reaction chamber; said trap having an inlet and an outlet, said inlet being connected to said reaction chamber, said trap having a residence time at least equal to one deposition cycle; and
a backing pump connected to said outlet of said trap and to exhaust.
2 . Apparatus as recited in claim 1 in which said inlet and said outlet are at the top of said trap.
3 . Apparatus as recited in claim 2 further comprising:
a process pump, said process pump being connected between said inlet of said trap and said reaction chamber.
4 . Apparatus as recited in claim 1 in which said residence time is greater than said deposition cycle.
5 . Apparatus as recited in claim 3 in which said trap further comprises:
a heater.
6 . Apparatus as recited in claim 3 in which said trap further comprises:
an electrode in said trap;
and a ground connection to said trap.
7 . Apparatus as recited in claim 1 further comprising:
a surge flow suppresser connected to said outlet of said trap.
8 . Atomic layer deposition apparatus comprising:
first and second precursor gas sources, first and second valves connected to said first and second precursor gas sources;
a purge gas source, said purge gas source having a third valve, said valve permitting inert gas flow, first and said second precursor gas sources and said purge gas operate sequentially to define a deposition cycle,
a reaction chamber, said reaction chamber being connected to said first, said second, and said third valves;
a trap connected to said reaction chamber; said trap having an inlet and an outlet, said inlet being connected to said reaction chamber, said trap having a residence time at least equal to one deposition cycle; and
a backing pump connected to said outlet of said trap and to exhaust.
9 . Apparatus as recited in claim 8 in which said inlet and said outlet are at the top of said trap.
10 . Apparatus as recited in claim 9 further comprising:
a process pump, said process pump being connected between said inlet of said trap and said reaction chamber.
11 . Apparatus as recited in claim 8 in which said residence time is greater than said deposition cycle.
12 . Apparatus as recited in claim 8 in which said trap further comprises:
a heater.
13 . Apparatus as recited in claim 8 in which said trap further comprises:
an electrode in said trap;
and a ground connection to said trap.
14 . A method of atomic layer deposition comprising the steps of:
sequentially flowing first and second precursor gases into a reaction chamber;
flowing a purge gas into said reaction chamber after said first and after second precursor gases, the flowing of said first and said second precursor gases and said purge gas forming a deposition cycle; and
removing the gaseous effluent from said reaction chamber in a trap, said removing including trapping the gaseous effluent in a trap, said gaseous effluent having a residence time in said trap at least equal to said deposition cycle.
15 . A method as recited in claim 14 in which said removing further comprises:
pumping said gaseous effluent with a backing pump after said trap.
16 . A method as recited in claim 14 in which said removing further comprises:
pumping said gaseous effluent with a process pump prior to said trap.
17 . A method as recited in claim 14 in which said residence time is greater than said deposition cycle.
18 . Deposition apparatus comprising:
first and second precursor gas sources, first and second valves connected to said first and second precursor gas sources;
a purge gas source, said purge gas source having a third valve, said valve permitting inert gas flow, first and said second precursor gas sources and said purge gas operate sequentially to define a deposition cycle,
a reaction chamber, said reaction chamber being connected to said first, said second, and said third valves; and
a trap connected to said reaction chamber; said trap having an inlet and an outlet, said inlet being connected to said reaction chamber, said trap having a residence time at least equal to one deposition cycle.
19 . Apparatus as recited in claim 18 further comprising:
a backing pump connected to said outlet of said trap and to exhaust.
20 . Apparatus as recited in claim 18 in which said inlet and said outlet are at the top of said trap.
21 . Apparatus as recited in claim 19 further comprising:
a process pump, said process pump being connected between said inlet of said trap and said reaction chamber.
22 . Apparatus as recited in claim 18 in which said residence time is greater than said deposition cycle.
23 . Apparatus as recited in claim 18 in which said trap further comprises:
a heater.
24 . Apparatus as recited in claim 18 in which said trap further comprises:
an electrode in said trap;
and a ground connection to said trap.
25 . Apparatus as recited in claim 18 further comprising:
a surge flow suppresser connected to said outlet of said trap.