Cleaning and liquid contact with solids – Processes – With work or work parts movable during treatment
Reexamination Certificate
2002-07-15
2004-08-03
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Processes
With work or work parts movable during treatment
C134S036000
Reexamination Certificate
active
06770151
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to substrate and semiconductor wafer preparation systems and methods, and more particularly, the present invention relates to the drying of substrates and semiconductor wafers following a wet cleaning or processing operation using a combination of an isopropyl alcohol (IPA) assisted Marangoni/Spin relatively low rotational speed drying technique, and a relatively high speed spin drying technique.
2. Description of the Related Art
In the fabrication of semiconductor devices, there is a need to perform wet cleaning of substrates at various stages of the fabrication process. Wet cleans are designed to wash away any by-products of the fabrication process, remove contaminants, and to achieve and maintain the necessary degree of cleanliness essential to proceed to a subsequent fabrication operation. As transistor device structures become smaller and more complex, the precision required to achieve and maintain structure definition demands exacting standards of cleanliness be maintained in all process operations. If a wet clean is incomplete or ineffective, or if a post-wet clean drying is incomplete or ineffective, then unacceptable residue or contaminants are introduced into the processing environment.
Rinsing and drying techniques, methods, and apparatus are plentiful and known in the art, and incorporate such operations as rinsing and scrubbing, immersion, and the application of thermal, mechanical, chemical, electrical, or sonic energy and the like to remove or displace water and dry the substrate. While some scrub and rinse operations may employ acids or bases for vigorous interaction with fabrication by-products, deionized water (DIW) is commonly used to perform a final rinse before the desired drying technique is performed.
One common drying technique is known as spin, rinse and dry (SRD). SRD uses mechanical, centrifugal, energy to rid the substrate of water by spinning the substrate until dry.
FIG. 1A
is a block diagram of a typical prior art SRD process. First DIW, or some other rinsing agent, is applied in block
10
to rinse and/or clean the substrate, and then in block
20
, the substrate is spun dry.
FIG. 1B
shows a typical SRD tool
30
. An SRD tool
30
typically includes a chuck
42
within a bowl
48
. The chuck
42
is mounted on a spindle
46
that is configured to rotate as shown by arrow
44
. A substrate
38
is attached to the chuck
42
with edge holding fingers
40
configured to maintain the substrate
38
in a horizontal orientation, firmly affixed to the chuck
42
so that spinning the chuck
42
on spindle
46
spins the substrate
38
and forces the DIW from the substrate
38
surface. DIW
36
, or other processing fluid, is typically dispensed from a dispensing nozzle
34
which is positioned over the substrate
38
at the end of a fluid dispensing arm
32
.
In some configurations, the substrate
38
is rinsed while the substrate
38
is spinning to ensure thorough rinsing, and then spun to dry. The spinning of the substrate
38
uses centrifugal energy to force water from the substrate
38
surface, and can be enhanced with the introduction of an inert gas such as Nitrogen or an inert gas vapor to displace any water that is not completely removed by spinning. Additional variations include heating the DIW, heating the SRD environment, heating the inert gas, and the like.
Another common drying technique is known as a Marangoni technique. Marangoni drying (not shown) typically includes using a chemical drying fluid or solvent such as isopropyl alcohol (IPA) to rinse the substrate after rinsing with DIW. The chemical drying fluid or solvent displaces the water on the surface of the substrate, evaporates, and the substrate is dried. Variations of the Marangoni technique also include the introduction of an inert gas such as Nitrogen to enhance evaporation of IPA and exclusion of oxygen, heating the Nitrogen, and the like.
Yet another drying technique that is evolving combines the Marangoni effect with the effects of centrifugal force. Generally, this combination of effects, hereinafter referred to as “Marangoni/Spin,” includes the application of DIW or other rinsing agent to a surface of a rotating substrate, and immediately following the application of the DIW with an application of a vapor or gaseous substance so that the vapor or gaseous substance mixes with a trailing edge of the rinsing agent. The trailing edge of the rinsing agent is that region of the film of the rinsing agent near a point of application of the rinsing agent to the surface of the substrate and away from which the liquid film of rinsing agent on the surface of the rotating substrate travels by centrifugal force towards the edge of the substrate.
In Marangoni/Spin drying, the mixing of the vapor or gaseous substance with the liquid rinsing agent on the surface of the rotating substrate produces a mixture that lowers the surface tension of the liquid rinsing agent at the point of mixing. The lowered surface tension forms a defined barrier between the liquid rinsing agent and the vapor or gaseous substance at the trailing edge of the liquid film of the rinsing agent. As the substrate is rotated, the liquid film is forced radially outward from a center region towards the edge of the rotating substrate by centrifugal force. The barrier between the liquid and vapor or gaseous substance confines the liquid portion to the liquid film, and as the film is forced towards the edge of the substrate, the surface of the substrate is left dry with substantially all of the liquid being removed from the surface of the substrate. For further information and discussion of Marangoni/Spin principles and techniques, reference is drawn to U.S. Pat. No. 5,882,433, issued Mar. 16, 1999, and to published European Patent Application EP 0 905 747 A1, published on Mar. 31, 1999, the disclosures of both of which are herein incorporated by reference.
FIG. 1C
shows a single-sided substrate drying tool
50
employing Marangoni/Spin drying techniques. The single-sided substrate drying tool
50
includes a chuck
58
mounted on a spindle
62
which is configured to rotate as shown by arrow
60
. A substrate
38
is positioned on chuck
58
so that the substrate
38
is spun during the drying process. One or more dispensing arms
52
are positioned over the rotating substrate
38
, and are configured to dispense a rinsing agent
56
on the surface of the spinning substrate
38
. A vapor or gaseous substance (not shown) is dispensed or introduced immediately following the dispensing of the liquid rinsing agent
56
. Nozzle
54
can be configured to dispense both the liquid, rinsing agent
56
and the vapor or gaseous substance, or two dispensing arms
52
can be configured immediately adjacent to one another such that as the dispensing arm
52
or arms are moved from a center region of the spinning substrate
38
towards the edge of the spinning substrate
38
, the liquid rinsing agent
56
is dispensed on the surface of the spinning substrate
38
and immediately followed by the vapor or gaseous substance. In this manner, the vapor or gaseous substance mixes with the liquid rinsing agent at the trailing edge of the film of liquid rinsing agent, lowering the surface tension of the liquid film of rinsing agent at the point of mixing, and traveling radially outward on the surface of the spinning substrate
38
as shown by directional arrow
64
.
Dual-sided wafer drying has become increasingly desired in substrate processing to meet stringent cleanliness requirements for ever more complex features. A significant limitation in the prior art is generally that methods and apparatus are not disclosed that enable dual-sided substrate drying.
FIG. 1C
is a typical example showing a single-sided substrate drying tool
50
that positions the substrate on a chuck which effectively blocks access to a backside of the substrate
38
. As can be appreciated, even if the illustrated chuck
58
could somehow be modified to provide access to t
deLarios John M.
Mikhaylichenko Katrina
Ravkin Michael
Chaudhry Saeed T
Lam Research Corporation
Martine & Penilla LLP
Stinson Frankie L.
LandOfFree
Drying a substrate using a combination of substrate... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drying a substrate using a combination of substrate..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drying a substrate using a combination of substrate... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3343379