U.S. patent application number 14/161066 was filed with the patent office on 2014-05-15 for apparatus for non-chemical, non-optical edge bead removal.
This patent application is currently assigned to Micron Technology, Inc.. The applicant listed for this patent is Micron Technology, Inc.. Invention is credited to Peter A. Benson.
Application Number | 20140130981 14/161066 |
Document ID | / |
Family ID | 32655309 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140130981 |
Kind Code |
A1 |
Benson; Peter A. |
May 15, 2014 |
APPARATUS FOR NON-CHEMICAL, NON-OPTICAL EDGE BEAD REMOVAL
Abstract
A method for removing the edge bead from a substrate by applying
an impinging stream of a medium that is not a solvent for the
material to be removed. The medium is applied to the periphery of
the substrate with sufficient force to remove the material. Also,
an apparatus to perform the inventive method.
Inventors: |
Benson; Peter A.; (Boise,
ID) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Micron Technology, Inc. |
Boise |
ID |
US |
|
|
Assignee: |
Micron Technology, Inc.
Boise
ID
|
Family ID: |
32655309 |
Appl. No.: |
14/161066 |
Filed: |
January 22, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13475515 |
May 18, 2012 |
8641831 |
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14161066 |
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10335279 |
Dec 31, 2002 |
8192555 |
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13475515 |
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Current U.S.
Class: |
156/345.55 ;
118/58 |
Current CPC
Class: |
H01L 21/67069 20130101;
H01L 21/6708 20130101; H01L 21/6715 20130101; H01L 21/67063
20130101; B08B 5/02 20130101 |
Class at
Publication: |
156/345.55 ;
118/58 |
International
Class: |
H01L 21/67 20060101
H01L021/67 |
Claims
1. An apparatus for semiconductor manufacturing, comprising: a
substrate support configured to hold a substrate comprising an edge
bead material proximate an outer edge of the substrate; a mechanism
configured to rotate the substrate support; a source of an edge
bead removing medium, the edge bead removing medium comprising a
non-solvent, non-aerosol gas and lacking solid particles; and a
device configured to deliver a high pressure stream of the edge
bead removing medium to a periphery of a substrate mounted on the
substrate support.
2. The apparatus of claim 1, wherein the device configured to
deliver the high pressure stream of the edge bead removing medium
comprises an air knife or nozzle.
3. (canceled)
4. (canceled)
5. The apparatus of claim 1, wherein the device configured to
deliver the high pressure stream of the edge bead removing medium
contains the edge bead removing medium.
6. The apparatus of claim 1, wherein the device configured to
deliver the high pressure stream of the edge bead removing medium
contains the non-solvent, non-aerosol gas without a liquid solvent
and without the solid particles.
7. (canceled)
8. The apparatus of claim 7, wherein the substrate is comprises a
semiconductor wafer.
9. (canceled)
10. The apparatus of claim 1, further comprising a source of
cleaning solution.
11. The apparatus of claim 10, further comprising a device
configured to deliver the cleaning solution onto at least one of a
periphery and an underside of the substrate.
12. An apparatus for semiconductor manufacturing, comprising: a
substrate support configured to hold a substrate; a mechanism
configured to rotate the substrate support; a device configured to
apply a coating material onto a substrate situated on the substrate
support; a source of a non-dissolving medium of the coating
material, the non-dissolving medium comprising a non-solvent,
non-aerosol gas and lacking solid particles; and a device
configured to deliver a high pressure stream of the non-dissolving
medium onto a periphery of the substrate situated on the substrate
support.
13. The apparatus of claim 12, further comprising: a source of
cleaning solution; and a device configured to deliver the cleaning
solution onto at least one of a periphery and an underside of the
substrate situated on the substrate support.
14. The apparatus of claim 13, wherein the source of cleaning
solution comprises a source of water.
15. The apparatus of claim 12, wherein the source of the
non-dissolving medium comprises a source of a gas selected from the
group consisting of air, a noble gas, and nitrogen gas.
16. The apparatus of claim 12, wherein the device configured to
apply the coating material onto the substrate comprises a device
configured to apply a photoresist material onto the substrate.
17. An apparatus for semiconductor manufacturing, comprising: a
substrate support configured to hold a substrate comprising an edge
bead material proximate an outer edge of the substrate; a mechanism
configured to rotate the substrate support; a source of a
non-solvent, non-aerosol gas lacking solid particles; a device
configured to deliver the non-solvent, non-aerosol gas lacking
solid particles onto a periphery of a substrate mounted on the
substrate support; a source of cleaning solution; and a device
configured to deliver the cleaning solution onto at least one of
the periphery and an underside of the substrate mounted on the
substrate support.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application
Ser. No. 13/475,515, filed. May 18, 2012, pending, which is a
divisional of U.S. patent application Ser. No. 10/335,279, filed
Dec. 31, 2002, now U.S. Pat. No. 8,192,555, issued Jun. 5, 2012,
the disclosure of each of which is hereby incorporated herein in
its entirety by this reference.
BACKGROUND OF THE INVENTION
[0002] The invention relates generally to the manufacture of
semiconductor devices. More particularly, the invention relates to
a non-solvent system for semiconductor wafer processes such as
removing the edge bead formed during spin coating processes.
[0003] Coating materials such as photoresist are typically applied
to a semiconductor wafer by flowing liquid coating material onto
the top surface of the wafer while it is spinning. The wafer is
held on a disk shaped, rotating spin chuck. The diameter of the
chuck is slightly less than the diameter of the wafer. The chuck is
positioned so that the wafer lies on the chuck in a level
horizontal plane. In operation, the backside or inactive surface of
the wafer is placed onto the chuck. The chuck applies a suction to
the backside of the wafer to hold the wafer in place on the chuck.
The chuck is rotated by a motor-driven axle that extends down from
the chuck. As the wafer is rotated on the chuck, liquid photoresist
material is applied to the center of the wafer. The photoresist
spreads radially outward from the center of the wafer towards the
edge to coat the top of the wafer. Ideally, all excess coating
material is ejected from the edge of the wafer. In practice,
however, some excess photoresist tends to collect at and form a
bead along the edge of the wafer.
[0004] Processes to remove the edge bead are known. Typically, a
solvent is dispensed along the edge of the wafer to dissolve the
edge bead and remove the resist from the extreme edge of the wafer.
If necessary, the coating is exposed to light prior to contact with
the solvent, or developer in order to develop the coating and
render it soluble in the solvent. The solvent may be dispensed
through a nozzle directed toward the backside edge of the wafer, in
which case it wicks up around to the top of the wafer to dissolve
the edge bead, or the solvent may be dispensed directly onto the
top edge of the wafer. In either case, the process allows solvent
and dissolved photoresist to be splashed about and often leaves a
jagged edge profile on the photoresist or other coating material.
In the process of U.S. Pat. No. 5,952,050, the method includes the
steps of dispensing a solvent selectively onto the edge of the
wafer to dissolve the coating material at the extreme edge of the
wafer, and applying a suction to vacuum excess solvent and
dissolved coating material from the wafer.
BRIEF SUMMARY OF THE INVENTION
[0005] The current invention is an edge bead removal method that
does not require the use of solvents or optical processing. In one
preferred embodiment, the invention is a method comprising the
steps of providing a substrate having an outer edge wherein at
least one material forms a coating layer on the outer edge of the
substrate; and removing material from the coating layer by
impinging the coated outer edge with a stream of a medium that is
not a solvent for the material.
[0006] In another preferred embodiment, an edge bead removal
method, the method comprising the steps of providing a substrate
having an outer edge wherein at least one material forms a coating
layer on the outer edge of the substrate and removing material from
the coating layer by impinging the coated outer edge with a stream
of a medium that is not a solvent for the material.
[0007] In yet another preferred embodiment, an edge bead removal
method, the method comprising the steps of providing a substrate
having an outer edge wherein at least one material forms a coating
layer on the outer edge of the substrate and removing material from
the coating layer by impinging the coated outer edge with a stream
of a gas that is not a solvent for the material.
[0008] In a further preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate and removing
material from the coating layer by impinging the coated outer edge
with a stream of an aerosol that is not a solvent for the
material.
[0009] In another preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge and an underside, wherein at least
one material forms a coating layer on the outer edge of the
substrate; removing material from the coating layer by impinging
the coated outer edge with a stream of a medium that is not a
solvent for the material; and applying a cleaning solution to the
outer edge or underside of the substrate to remove from the
periphery any residue remaining after the removal step.
[0010] Another preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge and an underside, wherein at least
one material forms a coating layer on the outer edge of the
substrate; removing material from the coating layer by impinging
the coated outer edge with a stream of a gas which is not a solvent
for the material; and applying a cleaning solution to the outer
edge or underside of the substrate to remove from the periphery any
residue remaining after the removal step.
[0011] A further preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge and an underside, wherein at least
one material forms a coating layer on the outer edge of the
substrate; removing material from the coating layer by impinging
the coated outer edge with a stream of an aerosol that is not a
solvent for the material; and applying a cleaning solution to the
outer edge or underside of the substrate to remove from the
periphery any residue remaining after the removal step.
[0012] Another preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; forming a
directed stream of a non-dissolving medium; and aiming the stream
of a non-dissolving medium to impinge the coated outer edge thereby
removing material from the coating layer.
[0013] Yet another preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; forming a
directed stream of a non-dissolving gas; and aiming the stream of a
non-dissolving medium to impinge the coated outer edge thereby
removing material from the coating layer.
[0014] Another preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; forming a
directed stream of a non-dissolving aerosol; and aiming the stream
of a non-dissolving medium to impinge the coated outer edge thereby
removing material from the coating layer.
[0015] In a further preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; forming a
directed stream of a non-dissolving medium; aiming the stream of a
non-dissolving medium to impinge the coated outer edge thereby
removing material from the coating layer; and applying a cleaning
solution to the periphery or underside of the substrate to remove
from the periphery any residue remaining after the removal
step.
[0016] In yet a further preferred embodiment, the invention is an
edge bead removal method, the method comprising the steps of
providing a substrate having an outer edge wherein at least one
material forms a coating layer on the outer edge of the substrate;
forming a directed stream of a non-dissolving gas; aiming the
stream of a non-dissolving gas to impinge the coated outer edge
thereby removing material from the coating layer; and applying a
cleaning solution to the periphery or underside of the substrate to
remove from the periphery any residue remaining after the removal
step.
[0017] In another preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; forming a
directed stream of a non-dissolving aerosol; aiming the stream of a
non-dissolving aerosol to impinge the coated outer edge thereby
removing material from the coating layer; and applying a cleaning
solution to the periphery or underside of the substrate to remove
from the periphery any residue remaining after the removal
step.
[0018] In a further preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; providing means
for forming a directed stream of a non-dissolving medium; forming a
directed stream of a non-dissolving medium; aiming the stream of a
non-dissolving medium to impinge the coated outer edge thereby
removing material from the coating layer; and applying a cleaning
solution to the periphery or underside of the substrate to remove
from the periphery any residue remaining after the removal
step.
[0019] In yet another preferred embodiment, the invention is an
edge bead removal method, the method comprising the steps of
providing a substrate having an outer edge wherein at least one
material forms a coating layer on the outer edge of the substrate;
providing means for forming a directed stream of a non-dissolving
medium; forming a directed stream of a non-dissolving gas; aiming
the stream of a non-dissolving gas to impinge the coated outer edge
thereby removing material from the coating layer; and applying a
cleaning solution to the periphery or underside of the substrate to
remove from the periphery any residue remaining after the removal
step.
[0020] In another preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; providing means
for forming a directed stream of a non-dissolving medium; forming a
directed stream of a non-dissolving aerosol with the stream foaming
means; aiming the stream of a non-dissolving aerosol to impinge the
coated outer edge thereby removing material from the coating layer;
and applying a cleaning solution to the periphery or underside of
the substrate to remove from the periphery any residue remaining
after the removal step.
[0021] In another preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; providing an
air knife or nozzle aimed at the outer edge of the substrate;
forming a directed stream of a non-dissolving medium; aiming the
stream of a non-dissolving medium to impinge the coated outer edge
thereby removing material from the coating layer; and applying a
cleaning solution to the periphery or underside of the substrate to
remove from the periphery any residue remaining after the removal
step.
[0022] In another preferred embodiment, the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; providing an
air knife or nozzle aimed at the outer edge of the substrate;
forming a directed stream of a non-dissolving gas; aiming the
stream of a non-dissolving gas to impinge the coated outer edge
thereby removing material from the coating layer; and applying a
cleaning solution to the periphery or underside of the substrate to
remove from the periphery any residue remaining after the removal
step.
[0023] Another preferred embodiment of the invention is an edge
bead removal method, the method comprising the steps of providing a
substrate having an outer edge wherein at least one material forms
a coating layer on the outer edge of the substrate; providing an
air knife or nozzle aimed at the outer edge of the substrate;
forming a directed stream of a non-dissolving aerosol; aiming the
stream of a non-dissolving aerosol to impinge the coated outer edge
thereby removing material from the coating layer; and applying a
cleaning solution to the periphery or underside of the substrate to
remove from the periphery any residue remaining after the removal
step.
[0024] In still another preferred embodiment, the invention is a
method for the manufacture of a semi-conductive wafer, comprising
the steps of applying a coating material to a top surface of the
semi-conductive wafer and spinning the wafer to form a film of
coating material on the top surface of the wafer; and contacting
the periphery of the coated spinning wafer with an impinging stream
of non-dissolving medium.
[0025] In yet another preferred embodiment, the invention is a
method for the manufacture of a semi-conductive wafer, comprising
the steps of applying a coating material to a top surface of the
semi-conductive wafer and spinning the wafer to form a film of
coating material on the top surface of the wafer; contacting the
periphery of the coated spinning wafer with an impinging stream of
non-dissolving medium; and applying a cleaning solution to the
periphery of the spinning wafer, the cleaning solution formulated
to react chemically with coated material to form a contaminant
compound that can be ejected from a spinning wafer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Preferred embodiments of the invention are described below
with reference to the following accompanying drawings, which are
for illustrative purposes only. Throughout the following views,
reference numerals will be used in the drawings, and the same
reference numerals will be used throughout the several views and in
the description to indicate same or like parts.
[0027] FIG. 1 shows a side schematic view of a process step for
applying a coating onto a substrate.
[0028] FIG. 2 shows a side view of a process step for removing the
edge bead.
[0029] FIG. 3 shows a side view of a process step for cleaning off
the edge bead residue.
DETAILED DESCRIPTION OF THE INVENTION
[0030] In the following detailed description, reference is made to
the accompanying drawings that form a part hereof and in which is
shown by way of illustration, specific embodiments in which the
invention may be practiced. These embodiments are described in
sufficient detail to enable those skilled in the art to practice
the invention, and it is to be understood that other embodiments
may be utilized, and that structural, chemical and process changes
may be made without departing from the spirit and scope of the
present invention.
[0031] The terms "wafer" or "substrate" used in the following
description include any semiconductor-based structure having a
silicon surface. Wafer and substrate are to be understood as
including silicon-on-insulator (SOI) or silicon-on-sapphire (SOS)
technology, doped and undoped semiconductors, epitaxial layers of
silicon supported by a base semiconductor foundation, and other
semiconductor structures. Furthermore, when references made to a
wafer or substrate in the following description, previous process
steps may have been used to form regions or junctions in the base
semiconductor structure or foundation.
[0032] The current invention uses a stream of a non-dissolving
medium to remove the edge bead from a substrate. The term
"non-dissolving medium" is equivalent to the term "nonsolvent" and
is used to designate that the material of the edge bead is
substantially insoluble in the medium. The edge bead is typically
formed when a coating, such as a photoresist, is applied to a
substrate. The edge bead frequently has an undesired thickness or
quality compared to the rest of the coating. Optionally, the
inventive process also includes wet cleaning to remove residual
particles remaining after the edge bead has been removed.
[0033] The substrate with the edge bead may be prepared as shown in
FIG. 1. In the illustration of FIG. 1, the substrate is a wafer 1.
Wafer 1 has a top surface 3, an outer edge 5, and a bottom surface
7. Wafer 1 is mounted on a vacuum mounting chuck 9 which in turn is
attached to a spindle 13. Typically, outer edge 11 of vacuum
mounting chuck 9 does not extend to the outer edge 5 of wafer 1.
Rotation of spindle 13 causes vacuum mounting chuck 9 and wafer 1
mounted thereto to spin also. While mounted wafer 1 is either
stationary or rotating at a slow speed, an application nozzle 15
applies coating material 17 to the center of wafer 1. The mounted
wafer 1 is then rapidly accelerated to a high rotational speed. The
centrifugal force of the rotation causes coating material 17 to
spread across the entire upper surface 3 of wafer 1. Coating
material 17 is typically a photoresist polymer. The spread of
coating material 17 is dependent upon a number of factors including
temperature of the wafer 1, temperature of coating material 17,
speed of rotation, and the viscosity of coating material 17. Excess
coating material 17 is ejected from edge 5 during the rotation or
wraps around to edge 5 and bottom surface 7. However, as shown in
FIG. 2 coating layer 19 of coating material 17 typically has edge
bead 21 proximate to outer edge 5 of wafer 1. Edge bead 21 may also
extend to cover outer edge 5 and the area of bottom surface 7 that
is proximate to outer edge 5.
[0034] The edge bead is removed from a substrate with an edge bead,
whether or not the substrate was prepared as illustrated in FIG. 1
and described above, by application of an impinging stream.
Preferably, the edge bead material is sufficiently removed from the
proximity of the edge to expose the top surface 3, outer edge 5 and
underside 7 of the substrate. In one embodiment, as shown in FIG.
2, an air knife 23 is positioned to direct a stream 25 of a
non-dissolving medium to impinge the edge bead 21 and outer edge 5
of wafer 1. Although this embodiment shows use of an air knife, any
means of generating a directed high pressure stream or column of
the non-dissolving medium may be used, such as a nozzle.
[0035] Air knife 23 typically includes a plurality of nozzles
through which the non-dissolving medium is forced and which are
aligned towards edge bead 21. Typically, the non-dissolving medium
is forced through these nozzles at a high pressure. The
non-dissolving medium may be any material that may be forced into a
high-pressure stream and that is not a solvent for coating material
17. The non-dissolving medium may be a gas, such as for example,
clean dry air, noble gas, or nitrogen. In other preferred
embodiments, the non-dissolving medium is a solid/gas aerosol.
Usable aerosols are known in the art, and preferably are argon or
carbon dioxide aerosols.
[0036] A typical aerosol-using edge bead removal method involves
cooling a gas, such as carbon dioxide or a mixture of argon and
nitrogen, to near the liquefication point of the gas and spraying
the cooled mixed gas through a nozzle into a low pressured chamber
such that a part of the mixed gas forms solid particles. The solid
particles as an aerosol in liquid and gas states collide with the
edge bead, thereby removing the material of the edge bead. Aerosols
and methods and nozzles for producing them, are further described
in U.S. Pat. Nos. 5,062,898; 5,294,261; 5,512,106; 5,931,721;
5,810,942; and 5,853,962, all of which are incorporated herein by
reference.
[0037] U.S. Pat. No. 5,062,898, discloses forming an aerosol
containing argon solid particles by expanding a pressurized gaseous
argon-containing stream, and removing particles or film on a
surface of a specimen using the formed aerosol. Also, it is
disclosed in the patent that a mixed gas containing argon gas is
cooled to near the liquefaction point at a fixed pressure range of
20 psi to 680 psi prior to the expanding.
[0038] U.S. Pat. No. 5,294,261, further describes the use of argon
with nitrogen-containing solid particles as well as an aerosol
containing argon-containing solid particles as cleaning source.
[0039] U.S. Pat. No. 5,512,106, discloses previously cooling a
mixture gas containing argon gas prior to supplying the mixture gas
to a nozzle, and that the mixture gas supplied to the nozzle
through the pre-cooling contains liquid drops of argon. The mixture
gas containing previously cooled argon liquid drops is injected
into a low pressured environment through the nozzle to thereby form
a fluid containing argon solid drops that are created through
adiabatic expansion and the fluid is then sprayed to a surface of a
specimen for the cleaning. U.S. Pat. No. 5,931,721, describes an
apparatus for performing the cleaning method provided in the
aforesaid U.S. Pat. No. 5,512,106.
[0040] U.S. Pat. No. 5,810,942, describes a hydrodynamic structured
chamber for spraying aerosol on a surface of a specimen for the
cleaning and allowing both of aerosol and objects such as particles
as removed to be easily extracted.
[0041] U.S. Pat. No. 5,853,962, discloses a method injecting a high
pressured liquefied CO.sub.2 through a nozzle, thereby transforming
the liquefied CO.sub.2 into soft solid CO.sub.2, and then spraying
the solid CO.sub.2 on a surface of a specimen, thereby removing
photoresist of organic material.
[0042] As shown in FIG. 3, the stream of non-dissolving medium 25
removes edge bead 21 from the proximity of outer edge 5 of wafer 1.
Removal of edge bead 21 can be, and preferably is, to such an
extent that an area 27 on upper surface 3 of wafer 1 adjacent to
outer edge 5 may be exposed.
[0043] Optionally, residue remaining after the removal of edge bead
21 may be removed by a wet cleaning process. One suitable wet
cleaning method is disclosed in U.S. Pat. No. 6,255,228 B1,
incorporated herein by reference. In this method, contaminants are
removed by applying a cleaning solution to the periphery and
preferably the exposed back side 7 of the wafer 1 after the edge
bead 21 has been removed. A nozzle 29 ejects a cleaning solution 31
onto the bottom 7 and outer edge 5 of wafer 1. Cleaning solution 31
wicks up around outer edge 5 and onto exposed section 27 to
dissolve or wash away any residual particles. The cleaning solution
may be water or may by formulated to react chemically with the
unwanted coating material residue to form a compound that may be
ejected from the periphery of the spinning wafer.
[0044] In compliance with the statute, the invention has been
described in language more or less specific as to structural and
methodical features. It is to be understood, however, that the
invention is not limited to the specific features shown and
described, since the means herein disclosed comprise preferred
forms of putting the invention into effect. The invention is,
therefore, claimed in any of its forms or modifications within the
proper scope of the appended claims appropriately interpreted in
accordance with the doctrine of equivalents.
* * * * *