Cleaning and liquid contact with solids – Apparatus – With plural means for supplying or applying different fluids...
Reexamination Certificate
2000-09-27
2002-11-19
Stinson, Frankie L. (Department: 1746)
Cleaning and liquid contact with solids
Apparatus
With plural means for supplying or applying different fluids...
C134S148000, C134S153000, C134S157000, C134S198000, C134S902000
Reexamination Certificate
active
06481447
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to semiconductor wafer cleaning and, more particularly, a fluid delivery ring to be utilized in semiconductor wafer spin, rinse, and dry (SRD) modules.
2. Description of the Related Art
Wafer preparation and cleaning operations are performed in fabrication of semiconductor devices. In one of such wafer preparation operations, a wafer is spin rinsed in a spin, rinse, and dry (SRD) module. A simplified schematic diagram of an exemplary prior art SRD module
100
is provided in FIG.
1
. As illustrated, the SRD module
100
includes a bowl
102
rigidly mounted on an SRD housing
118
. The SRD housing
118
has a bore to receive a shaft
117
, which is coupled to a motor
116
. The motor
116
causes the shaft
117
and thus the spindle
106
and a wafer
102
to rotate in a rotation direction
112
. A chuck
110
extends through the bowl
102
and is mounted on a spindle
106
. A seal
126
is defined between the spindle
106
and the shaft
117
in order to prevent chemicals from exiting the SRD module. Four spindle fingers
108
coupled to the chuck
110
, support the wafer
104
along its edges. In the SRD module
100
, the chuck
110
moves vertically in the movement direction
114
. As such, the chuck
110
moves upwardly in the bowl
102
such that it extends outside the bowl
102
and above bowl lips
102
a.
Once the wafer
104
is delivered to the spindle fingers
108
at a level above the bowl lips
102
a,
the chuck
110
moves downward and back into the bowl
102
such that the wafer
104
is disposed below the bowl lips
102
a.
A backside rinse nuzzle
124
mounted on the inner surface of bottom wall of the bowl
102
sprays liquid (e.g., DI water) onto the bottom side of the wafer
104
. A spigot
120
is disposed above the bowl
102
and above the wafer
104
. A fluid (e.g., DI water) supplied to the spigot
120
through a tube
122
is sprayed onto the surface of the wafer
104
as the wafer is spun at high revolutions per minute (RPMs). The spigot is designed to move horizontally, in the spigot movement direction
121
. At the conclusion of the rinsing operation, the accumulated fluid is drained through the drain port
128
defined in the bottom wall of the bowl
102
as well as the bottom wall of the SRD housing
118
. Once the surface of the wafer
104
and the bottom of the wafer
104
are sprayed with fluid, the supplying of fluid is stopped by turning off the spigot
120
. Thereafter, the wafer
104
is dried by being spun at high RPMs. As soon as the wafer is dried, the chuck
110
is once again moved upward from within the bowl
102
and is extended to the outside of the bowl
102
and the bowl lips
102
a
so as to unload the processed wafer
104
.
Several problems can be associated with the conventional SRD module
100
. One primary concern associated with the conventional SRD module is the use of a single spigot for fluid delivery onto the surface of the wafer. One problem with the use of the single point fluid delivery spigot is that such system fails to yield an optimum rinsing operation as some portions of the wafer may not be exposed to sufficient amount of rinsing fluid. A second major problem is that the use of spigots may result in the recontamination of a processed wafer. This occurs because even after the fluid delivery has seized, excess liquid still remains in the spigot
120
. As such, frequently, the excess fluid (e.g., DI water) remained in the spigot
120
flows out of the spigot
120
and drips on an otherwise clean surface of the wafer
104
recontaminating the surface of the processed wafer (e.g., causing stains or particulate spots). When such dripping occurs, the SRD operation must be repeated again (if detected), thereby reducing throughput as a result of increasing the overall time expended in the SRD module. If the problem is undetected, the quality of the cleaning goes down.
Another problem associated with the typical SRD module is having chemically incompatible components. In a typical SRD module, the chuck
110
is usually made out of Aluminum, the bowl
102
is made out of polyurethane, and the spigot is made out of stainless steal. These components may enter into chemical reactions with the fluids introduced into the SRD module. As a consequence, further contaminants may be introduced into the SRD module. For instance, as the chuck
110
moves up and down within the bowl
102
, some of its coating flakes off of the chuck thus generating particulates and contaminants inside the bowl
102
and the SRD module
100
. These contaminants may react with the residual chemicals (e.g., HF, NH
3
OH, etc.) present in the SRD module from the previous operation of brush scrubbing of the wafer surfaces. As a result of such chemical reactions between the generated particulates and contaminants of the chuck
110
with the residual chemicals, the wafer
104
as well as the SRD module is recontaminated.
In addition to introducing contaminants, the typical SRD module utilizes a chuck having an extremely complex design. In the conventional SRD module, the chuck
110
moves up and down through the bowl
102
to receive and deliver the wafer
104
. As such, it is imperative that the chuck remain properly calibrated so that it comes to rest at the exact orientation. In situations where the chuck is not properly aligned, the failure to properly receive and deliver the wafer, mandates the realignment of the chuck. The process of realigning the chuck is very time consuming and labor intensive. Consequently, in order to realign the chuck, the SRD module must be taken off-line for an extended period of time thus reducing the throughput.
In view of the foregoing, a need therefore exists in the art for a chemically compatible SRD module that enables efficient rinsing of a surface of a substrate without recontaminating the substrate surface.
SUMMARY OF THE INVENTION
Broadly speaking, the present invention fills these needs by providing an apparatus and related methods for optimizing the rinsing operation of a spin, rinse, and dry (SRD) module. Preferably, the SRD module is constructed from chemically compatible components and is designed to facilitate uniform delivery of rinsing fluid onto a surface of a substrate to be rinsed. The SRD module is configured to include a delivery ring having a plurality of ring inlets and a plurality of opposing ring outlets wherein the number of ring inlets are equivalent to the number of ring outlets. Also included are a plurality of slots defined between each ring inlet and its respective opposing outlet. In one embodiment, a plurality of supply tubes are configured to deliver rinsing fluid onto the surface of the substrate utilizing the plurality of the ring inlets, the ring outlets, and the slots. It should be appreciated that the present invention can be implemented in numerous ways, including as a process, an apparatus, a system, a device, or a method. Several inventive embodiments of the present invention are described below.
In one embodiment, a fluid delivery module for use in preparing a substrate is disclosed. The fluid delivery module includes a process bowl designed to contain a substrate to be prepared. The process bowl has a bottom wall and a sidewall. Also included in the fluid delivery module is a fluid delivery ring configured to be attached to the sidewall of the process bowl. The fluid delivery ring includes a plurality of inlet and outlet pairs. Each of the plurality of inlet and outlet pairs is defined in the fluid ring and is designed to receive a respective supply tube. Each respective supply tube has an end that terminates at each of the outlets of the fluid delivery ring and is configured to direct fluid onto a surface of the substrate.
In another embodiment, a method for making a fluid delivery ring is disclosed. The method starts by generating a solid ring having a side surface, a top surface, and an under surface. Then, a plurality of slots are formed into the under surface of the solid ring. Each of
Smith Stephen M.
Treur Randolph E.
Lam Research Corporation
Martine & Penilla LLP
Stinson Frankie L.
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