U.S. patent application number 15/153593 was filed with the patent office on 2016-09-08 for method and apparatus for planarization of substrate coatings.
The applicant listed for this patent is Taiwan Semiconductor Manufacturing Company, Ltd.. Invention is credited to Ching-Yu Chang, Yu-Chung Su, Wen-Yun Wang, Cheng-Han Wu.
Application Number | 20160260623 15/153593 |
Document ID | / |
Family ID | 51529007 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160260623 |
Kind Code |
A1 |
Wang; Wen-Yun ; et
al. |
September 8, 2016 |
Method and Apparatus for Planarization of Substrate Coatings
Abstract
A system for forming a coating comprises applying a first
coating to a substrate having a plurality of topographical
features, planarizing a top surface of the first coating, and
drying the first coating after planarizing the top surface. The
first coating may be applied over the plurality of topographical
features, and may be substantially liquid during application. The
first coating may optionally be a conformal coating over
topographical features of the substrate. The conformal coating may
be dried prior to planarizing the top surface of the first coating.
A solvent may be applied to the conformal coating, with the top
surface of the conformal coating being substantially planar after
application of the solvent. The first coating may have a planar
surface prior to drying the first coating, and the first coating
may be dried without substantial spin-drying by modifying an
environment of the first coating.
Inventors: |
Wang; Wen-Yun; (Taipei City,
TW) ; Wu; Cheng-Han; (Taichung City, TW) ; Su;
Yu-Chung; (Hsin-Chu, TW) ; Chang; Ching-Yu;
(Hsin-Chu, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Taiwan Semiconductor Manufacturing Company, Ltd. |
Hsin-Chu |
|
TW |
|
|
Family ID: |
51529007 |
Appl. No.: |
15/153593 |
Filed: |
May 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13800627 |
Mar 13, 2013 |
9349622 |
|
|
15153593 |
|
|
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|
61778298 |
Mar 12, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/0273 20130101;
H01L 21/67063 20130101; G03F 7/162 20130101; B05B 13/0228 20130101;
H01L 21/31055 20130101; B05B 12/02 20130101; H01L 21/67028
20130101; H01L 21/31051 20130101; B05D 1/005 20130101; H01L
21/31058 20130101; H01L 21/02282 20130101; H01L 21/6715
20130101 |
International
Class: |
H01L 21/67 20060101
H01L021/67; H01L 21/02 20060101 H01L021/02; G03F 7/16 20060101
G03F007/16; B05B 13/02 20060101 B05B013/02; B05B 12/02 20060101
B05B012/02; H01L 21/3105 20060101 H01L021/3105; H01L 21/027
20060101 H01L021/027 |
Claims
1. A system for applying a coating, the system comprising: a
chamber having: a platen configured to hold a wafer; a first nozzle
configured to deliver a first coating to the wafer, the chamber
configured to first dry the first coating, wherein the platen is
configured to spin the wafer at a first speed during delivery of
the first coating to the wafer, the platen further configured to
spin the wafer at a second speed during first drying of the first
coating; and a second nozzle configured to deliver a solvent to the
first coating after first drying to re-liquefy the first coating, a
top surface of the first coating achieving a substantially planar
state after application of the solvent, the chamber further
configured to second dry the first coating after delivery of the
solvent, the first coating having a substantially planar top
surface after second drying.
2. The system of claim 1, wherein: the first coating is a conformal
coating conforming to topographical features on the wafer; and the
chamber is configured to planarize the top surface of the conformal
coating after drying the conformal coating.
3. The system of claim 2, wherein: the chamber is further
configured to planarize the top surface of the first coating by
applying a solvent to the conformal coating, the solvent reflowing
the coating to produce a reflowed first coating; and the chamber is
further configured to dry the reflowed first coating.
4. The system of claim 1, wherein the platen is further configured
to vibrate the wafer during application of the first coating and
during drying of the first coating.
5. The system of claim 1, wherein the chamber is configured to dry
the first coating by controlling an environment contained in the
chamber.
6. The system of claim 5, wherein the chamber is configured to
control the environment by modifying at least one of a gas
pressure, a gas flow rate, or a temperature.
7. The system of claim 1, further comprising a thickness monitor
configured to measure a thickness of the first coating, wherein the
chamber is configured to apply a second coating on the top surface
of the first coating, the second coating having a thickness
depending on at least the thickness of the first coating.
8. An apparatus for forming a coating, the apparatus comprising: a
coating chamber having a platen configured to hold a substrate; a
first nozzle configured to deliver a first coating in a liquid
state to the substrate, the substrate having a non-planar top
surface, the coating chamber configured to first dry the first
coating, wherein the platen is configured to spin the substrate at
a first speed during delivery of the first coating to the
substrate, the platen further configured to spin the substrate at a
second speed during first drying of the first coating; and a second
nozzle configured to deliver a solvent to the first coating after
first drying to re-liquefy the first coating, a top surface of the
first coating achieving a substantially planar state after
application of the solvent, the coating chamber further configured
to second dry the first coating after delivery of the solvent, the
first coating having a substantially planar top surface after
second drying, wherein the top surface of the first coating is
planarized prior to second drying the first coating.
9. The apparatus of claim 8, wherein the solvent is configured to
reflow at least a portion of the first coating.
10. The apparatus of claim 8, wherein the platen is further
configured to spin the substrate at a first speed during
application of the first coating, and spin the substrate at a
second speed lower than the first speed during the first
drying.
11. The apparatus of claim 8, wherein the platen is further
configured to vibrate the substrate during application of the first
coating and during drying of the first coating.
12. The apparatus of claim 8, wherein the coating chamber is
configured to dry the first coating by controlling an environment
contained in the coating chamber.
13. The apparatus of claim 12, wherein the coating chamber is
configured to control the environment by modifying at least one of
a gas pressure, a gas flow rate, or a temperature.
14. The apparatus of claim 8, further comprising a thickness
monitor configured to measure a thickness of the first coating,
wherein the coating chamber is configured to apply a second coating
on a planar top surface of the first coating, the second coating
having a thickness depending on at least the thickness of the first
coating measured by the thickness monitor.
15. A device for applying a coating, the device comprising: a
chamber having: a platen configured to hold a wafer, the wafer
having a plurality of topographical features disposed thereon; a
first nozzle configured to deliver a first coating over the
plurality of topographical features, the chamber configured to
first dry the first coating to a solid state, wherein the platen is
configured to spin the wafer at a first speed during delivery of
the first coating, the platen further configured to spin the wafer
at a second speed during first drying of the first coating; and a
second nozzle configured to deliver a solvent to the first coating
after first drying to re-liquefy the first coating, the chamber
further configured to second dry the first coating after delivery
of the solvent, the first coating having a substantially planar top
surface after second drying.
16. The device of claim 15, wherein the first coating is a
conformal coating, and the chamber is configured to planarize a top
surface of the conformal coating after drying the conformal
coating.
17. The device of claim 16, wherein: the chamber is further
configured to planarize a top surface of the first coating by
applying a solvent to the conformal coating, the solvent reflowing
the coating to produce a reflowed first coating; and the chamber is
further configured to dry the reflowed first coating.
18. The device of claim 15, wherein the platen is further
configured to vibrate the wafer during application of the first
coating and during drying of the first coating.
19. The device of claim 15, wherein the chamber is configured to
dry the first coating by controlling at least one environmental
parameter of the chamber.
20. The device of claim 19, wherein the chamber is configured to
control at least one of a gas pressure, a gas flow rate, or a
temperature.
Description
PRIORITY CLAIM
[0001] This application is a divisional and claims the benefit of
U.S. patent application Ser. No. 13/800,627, filed on Mar. 13,
2013, entitled "Method and Apparatus for Planarization of Substrate
Coatings," which application claims the benefit of U.S. Provisional
Application No. 61/778,298, filed on Mar. 12, 2013, entitled
"Method and Apparatus for Planarization of Substrate Coatings,"
which applications are hereby incorporated herein by reference.
BACKGROUND
[0002] Semiconductor devices are used in a variety of electronic
applications, such as personal computers, cell phones, digital
cameras, and other electronic equipment, as examples. Semiconductor
devices are typically fabricated by sequentially depositing
insulating or dielectric layers, conductive layers, and
semiconductor layers of material over a semiconductor substrate,
and patterning the various material layers using lithography to
form circuit components and elements thereon.
[0003] The semiconductor industry continues to improve the
integration density of various electronic components (e.g.,
transistors, diodes, resistors, capacitors, etc.) by continual
reductions in minimum feature size, which allow more components to
be integrated into a given area. These smaller electronic
components also require smaller packages that utilize less area
than packages of the past.
[0004] Substrate coatings such as photoresists, polymer coatings
and the like are used during the production and finishing processes
for semiconductor dies. Those coatings are sometimes "spun on" to a
substrate, with a liquid being applied to a substrate and then spun
to distribute the coating on the substrate. Subsequent processing
steps such as photoresist patterning, post-passivation layer
interconnect layers or the like may be applied over the spun on
coatings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For a more complete understanding of the present disclosure,
and the advantages thereof, reference is now made to the following
descriptions taken in conjunction with the accompanying drawings,
in which:
[0006] FIG. 1 illustrates an apparatus for applying a planar
substrate coating according to an embodiment;
[0007] FIGS. 2A-2D and 3A-3C are cross-sectional views of
intermediate process steps in forming a planar substrate coating
according to various embodiments; and
[0008] FIG. 4 is a flow diagram illustrating a method for forming a
planar substrate coating according to an embodiment.
[0009] Corresponding numerals and symbols in the different figures
generally refer to corresponding parts unless otherwise indicated.
The figures are drawn to illustrate the relevant aspects of the
embodiments and are not necessarily drawn to scale.
DETAILED DESCRIPTION
[0010] The making and using of the presented embodiments are
discussed in detail below. It should be appreciated, however, that
the present disclosure provides many applicable concepts that can
be embodied in a wide variety of specific contexts. The specific
embodiments discussed are merely illustrative of specific
apparatuses and ways to make and use the planar substrate coating,
and do not limit the scope of the disclosure.
[0011] Embodiments will be described with respect to a specific
context, namely making and using planar coatings useful in, for
example, semiconductor device manufacturing processes such as
coatings for packaging, passivation layers, molding compounds, or
the like, or another type of planar coating.
[0012] The embodiments of the present disclosure are described with
reference to FIGS. 1 through 4, and variations of the embodiments
are also discussed. Throughout the various views and illustrative
embodiments of the present disclosure, like reference numbers are
used to designate like elements. Additionally, the drawings are
intended to be illustrative, are not to scale and not intended to
be limiting. Note that, for simplification, not all element numbers
are included in each subsequent drawing. Rather, the element
numbers most pertinent to the description of each drawing are
included in each of the drawings.
[0013] The application of a coating to a wafer is a technique
sometimes used in, for example, semiconductor fabrication.
Generally, a conformal coating attempts to form a layer of constant
thickness over a surface. Often times, however, conformal coating
results in thickness variances between topographically dense and
isolated areas as well as a nonplanar top surface that may create
inconsistencies or errors in subsequent processing steps.
Non-uniformity of the coating may be particularly evident where a
wafer has high aspect ratio topographic features. Usually coating
at the topographically dense areas will be thicker than in isolated
areas.
[0014] In an embodiment, a photoresist may be applied as a liquid
and then cured and baked prior to patterning. Similarly, a coating,
such as, for example, post-passivation layers such as polymers or
protective layers may be applied over a passivation layer or
redistribution layer. It has been discovered that a planar surface
on an applied coating may result in superior performance of the
coating.
[0015] The non-uniform top coating surface of a conformal coating
may lead to poor focus leveling, upper-layer peeling, or
non-uniform loading during planarization steps such a
chemical-mechanical polishing (CMP). For example, where a
photoresist is used, the varied topography of a conformal coating
surface may result in a less accurate photolithographic masking of
the photoresist due to inconsistent focus leveling. In another
example, where a polymer or protective layer is coated on a
non-planar surface, a conformal coating may result in poor
performance or inaccurate formation of post-passivation
interconnects or other subsequent features. In contrast, a coating
with a relatively flat top surface or a surface free of substantial
topological variation permits more accurate post-coating
processing.
[0016] FIG. 1 illustrates a coating apparatus 100 for applying a
planar substrate coating according to an embodiment. A coating
apparatus 100 may comprises a coating chamber 102 with a platen 106
configured to retain a wafer 104. A coating nozzle 108 may be
disposed in the coating chamber 102 and may be configured to apply
a coating to a surface of the wafer 104 when the wafer 104 is
disposed on the platen 106. A thickness monitor 114 may also be
disposed in the coating chamber 102 and may be configured to take
measurements of coating thickness on the wafer 104. The coating
chamber 102 may further have an inflow opening 112 and an outflow
opening 110 permitting gas exchange in the coating chamber 102.
[0017] In an embodiment, the coating chamber 102 may be a sealed,
or clean, environment in which a wafer 104 is processed. The
coating chamber 102 may also have one or more heating elements (not
shown) or otherwise be configured to control the temperature of the
environment contained in the coating chamber 102. The coating
chamber 102 may also be configured to control other factors related
to the environment of the coating chamber, including, but not
limited to, the pressure or partial pressure of one or more gases,
the humidity, the flow rate of gases in and/or out of the coating
chamber 102, or any other number of factors. The inflow opening 112
and outflow opening 110 may be manipulated to control the
environment by, for example, controlling the flow rate of gas
through the coating chamber 102.
[0018] A wafer 104 may be loaded onto the platen 106, which may
retain the wafer 104, through, for example, a vacuum chuck, an
adhesive, a physical retainer such as a clip, or another suitable
retaining method. The platen 106 may be configured to rotate at one
or more preselected speeds, with the platen 106 able to stop or
rotate during coating application and after the coating
application. In an embodiment, the platen 106 may rotate at a first
speed during the coating application, and after coating
application, or after a predetermined time after the coating
application, may rotate at a second lower speed. For example, the
platen 106 may rotate at 100 RPM during application of the coating
in order to ensure even distribution of the coating on the wafer
104 surface. After the coating is applied, the platen 106 may slow
rotation to, for example, 20 RPM, or may stop completely for
subsequent processing steps.
[0019] The platen 106 may be further configured to vibrate or shake
the attached wafer 104. In an embodiment, the platen 106 may
vibrate at a frequency between about 10 Hz and 10 MHz. The platen
106 may vibrate the wafer 104 during application of the coating, or
any time after application of the coating. Vibrating the wafer 104
during the coating application may cause the coating to settle more
evenly over the surface of the wafer 104, causing the coating to
settle into voids, valleys or the like between topography features
on the wafer 104 (e.g., a non-planar top surface). Furthermore, any
bubbles or other imperfections in the coating may be released from
under the surface of the coating prior to the coating drying.
Removing bubbles and ensuring a consistent application of the
coating reduces errors in later processing. For example, a
photoresist coating may develop bubbles in the coating when
applied. Releasing the bubbles in the photoresist permits the
bubbles to come to the surface and pop so that the bubbles will not
interfere with the photoresist patterning. When the photoresist is
patterned via photolithography, the resulting photoresist mask is
more consistent with the intended pattern since bubbles that may
have distorted the photo patterning have been reduced or
removed.
[0020] In an embodiment, the coating nozzle 108 may be arranged
facing the wafer 104 and may be configured to deliver one or more
materials to the surface of the wafer 104. The coating nozzle 108
may be configured to spray a coating in liquid or aerosolized form
onto the wafer 104, but may also be configured to separately
deliver additional materials such as a buffer solvent, a coating
reflow solvent, a rinse material, or the like.
[0021] The thickness monitor 114 may be a measurement device used
to measure the thickness of a coating as applied, or during or
after coating processing. In an embodiment, the thickness monitor
114 may be an inline ellipsometer, reflective thickness monitor, or
a non-contact thickness measurement device.
[0022] FIG. 2A is a cross-sectional view illustrating an initial
wafer 104 with topographical features 202 according to an
embodiment. In an embodiment, a coating may be applied to the wafer
104 and planarized prior to drying to a solid state. The wafer 104
may be a semiconductor wafer, a die wafer, a workpiece, or any
other structure that will have a coating applied. The wafer 104 may
be attached to the platen 106 for coating as described above. In an
embodiment, the wafer 104 may comprise one or more topographical
features 202. For example, the wafer 104 may have one or more
FinFET devices being formed thereon, where the topographical
features 202 are fins, gates, or the like, and the coating may be a
photoresist to be patterned for etching or metal layer deposition.
In another example, the topographical features 202 may be planar
transistors gate structures, RDL layers, metal layers, or the like.
In an embodiment, the topographical features 202 may be greater
than about 50 nm high.
[0023] FIG. 2B is a cross-sectional view illustrating application
of a coating 204 to a wafer 104 according to an embodiment. The
coating 204 may be a polymer or other material carried in water, a
solvent such as an alcohol, an organic material, or the like. In an
embodiment, the coating may be applied as a liquid, or as an
aerosol building a film on the surface of the wafer 104. The
coating 204 may be applied thicker than the target thickness to
account for shrinkage of the coating 204 as it dries. The coating
204 may be applied to a thickness between about 5 times and about
10,000 times as thick as the target thickness of the coating 204.
The target thickness of the coating 204 will, in an embodiment, be
a predetermined thickness, and may be greater than the greatest
height of the topographical features 202. Thus, the final coating
will be at a height that rises higher than, and covers, the
topographical features 202. In an embodiment, the coating 204 will
have a planar top surface 204a while still substantially liquid,
and will retain the planar top surface 204a during subsequent
drying.
[0024] The platen 106 may spin the wafer 104 during application of
the coating 204 to ensure that the coating 204 flows into recesses
between the topographical features 202. In an embodiment, the
platen 106 may also vibrate the wafer 104 as the coating 204 is
applied to aid in the coating 204 flowing into the recesses between
the topographical features 202 as well as releasing any air pockets
or bubbles that may form during application of the coating 204. In
an embodiment, the coating 204 may have a surface tension of less
than about 50 dyne/cm after application.
[0025] Application of the coating 204 may comprise applying a
buffer solvent to the wafer 104 prior to applying the coating 204.
The buffer solvent may be applied to maintain the liquidity or
viscosity of the coating 204 during application, or to ensure that
the coating 204 does not dry prematurely.
[0026] FIG. 2C is a cross-sectional view illustrating drying of the
coating 204 according to an embodiment. The coating 204 may be
dried by evaporating the solvent in the coating 204, with the
evaporation of the solvent being primarily performed by controlling
the environment of the coating chamber. In such an embodiment, the
coating may be dried without spin-drying. The coating 204 may be
dried to have a top surface 204a with a surface topography having
features varying less than about 10 nm.
[0027] In an embodiment, the temperature and environmental
parameters of the coating chamber 102 may be controlled to cause
drying of the coating 204. The coating 204 may be dried while the
platen 106 is at a reduced spin speed, or while the platen 106 is
stopped. The platen 106 may have its spin stopped or slowed before
the applied coating 204 sets, cures, or dries, permitting the
coating 204 to settle and then dry with a substantially planar top
surface 204a. For example, the coating 204 may be applied while the
platen 106 spins at about 100 RPM, and the platen 106 speed may be
reduced to, for example, 20 RPM for a period to permit the coating
204 to settle or slump and form a planarized top surface 204a. The
platen 106 may also be vibrated at a first speed, for example, 100
Hz, during application of the coating 204 to settle the coating
204, and may be vibrated at 10 KHz during after application of the
coating 204 and prior to drying to release any bubbles in the
coating 204. The reduced spin speed during drying may permit the
coating 204 to retain a substantially planar top surface 204a
during drying.
[0028] In an embodiment, the conditions in the coating chamber 102
such as temperature or platen 106 spin speed may be monitored and
controlled by a controller such as a production management system,
by an integrated controller, by a general purpose computer in
signal communication with the coating chamber, by manual
adjustment, or another suitable system.
[0029] In an embodiment, the coating chamber 102 may bring the
environment temperature up to between about 30.degree. C. and about
250.degree. C. and the wafer 104 with coating 204 may then be held
in the coating chamber 102 at the elevated temperature until the
coating 204 dries. The coating chamber 102 may also manage or
control the pressure and gas flow to the coating chamber 102
separately from, or in combination with, the temperature, to ensure
sufficiently controlled drying of the coating 204. For example, the
coating chamber 102 may flow air through the coating chamber 102 at
a rate between about 50 ml/min and about 50 1/min, and the pressure
in the coating chamber 102 may be maintained at a pressure between
about 300 Pa and 1 MPa. The inflow opening 112 and outflow opening
110 may be controlled to maintain a predetermined pressure and gas
flow rate through the coating chamber 102. It will be recognized
that the rate of drying for the coating 204, or the rate of solvent
evaporation, may be controlled through control of the temperature,
gas flow, gas pressure, or the like.
[0030] Skilled practitioners will recognize that the platen 106
spin speed and vibration frequency and coating chamber 102
temperatures, pressures and gas flow rates may depend on the
desired coating 204 thickness, the viscosity of the coating 204
when applied, the speed with which the coating 204 dries, the size
of the wafer, or one or more other factors, and that the exemplary
conditions may be adjusted to provide efficient processing of
various coatings and wafers.
[0031] Drying the coating 204 may result in the coating having a
height about equal to the predetermined final coating height. In an
embodiment, the coating 204 may have a solvent or carrier when
applied, and the drying may force the solvent from the coating 204,
resulting in a coating thickness that is lower than the thickness
of the coating 204 when applied.
[0032] FIG. 2D is a cross-sectional view illustrating application
of a second coating 206 according to an embodiment. The second
coating 206 may be applied to the top surface 204a of the coating
204 to bring the overall coating height to a predetermined depth.
The thickness monitor 114 may determine the depth of the coating
204 and the second coating 206 may be applied to compensate for any
variance from a desired thickness. In an embodiment, the coating
top surface 204a may be substantially planar, and so application of
the second coating 206 may be performed by a spin-on and spin-dry
process since most topographical variations will have been
compensated for by the coating 204.
[0033] FIG. 3A is a cross-sectional view illustrating application
and drying of a coating 204 to a wafer 104 according to an
embodiment. In an embodiment, the coating 204 may be applied to the
wafer 104 and dried prior to planarization. In such an embodiment,
the coating 204 may be applied conformally, with the coating top
surface 204a having variations in topography. The wafer 104 may be
intentionally coated with a conformal coating 204 by spin drying
the coating 204. The conformal coating 204 may also be a result of
insufficient planarization under a coating method, for example,
such as in the embodiment described with respect to FIGS.
2A-2D.
[0034] FIG. 3B is a cross-sectional view illustrating planarization
of a conformal coating 204 according to an embodiment. A solvent
may be applied to the dried, conformal coating 204 to dissolve or
reflow (e.g., re-liquefy) a portion of the coating 204. In such an
embodiment, the coating 204 will achieve a substantially planar top
surface 204a during reflow, or in a liquid state, and retain that
planar top surface 204a during and after drying.
[0035] In an embodiment, the solvent may be, for example, an
organic solvent or water, or a hybrid with a surfactant to reduce
the reflowed coating surface tension. The surfactant structure may
be a hydrocarbon with, for example, 1 to about 25 carbon atoms
arranged in a straight, branched or cyclic structure. In an
embodiment, the surfactant may have a R.sub.1--(--O).sub.n--R.sub.2
structure where n is 1 to about 15. R.sub.1 and R.sub.2 may be
alkyl groups that may comprise heterostructures such as nitrogen,
oxygen, or fluorine. R.sub.1 and R.sub.2 may also comprise nitro-
or sulfonic-groups or double or triple bond alkyl structures.
[0036] The coating 204 may be vibrated or spun, or a combination of
the foregoing, during coating reflow to cause the reflowed coating
204 to settle or planarize. After the reflowed coating 204 achieves
a substantially planar top surface 204a, the coating 204 may be
dried again to drive off any solvent and surfactant, solidifying
the planar coating 204.
[0037] FIG. 3C is a cross sectional view illustrating application
of a second coating according to an embodiment. The thickness of
the coating 204 after reflow may be measured, for example, by the
thickness monitor 114, and the second coating 206 applied to
compensate for deviation form a desired thickness in the coating
204. In an embodiment, the coating may be applied to have a
thickness sufficient to cover the topographic features 202 on the
wafer 104, and reflowed to fill any recesses between the
topographic features 202. The second coating 206 may be
subsequently applied to bring the overall coating height to a
desired or predetermined thickness.
[0038] FIG. 4 is a flow diagram illustrating a method 400 for
forming a planar coating according to an embodiment. A substrate or
wafer may be provided in block 402. The wafer may have one or more
topographic features disposed on a first side. A coating may be
applied to the first side of the wafer in block 404. In an
embodiment, the wafer may be spun, vibrated, or otherwise
manipulated during coating application to distribute the coating
over the surface of the first side of the wafer. In an embodiment,
the coating may be planarized or leveled in block 412. Planarizing
the coating may comprise spinning, vibrating or otherwise
manipulating the coating to cause conformation portions of the
coating to settle and to cause the top surface of the coating to
achieve a substantially planar state. The coating may be dried by
way of temperature and air flow in block 414. In such an
embodiment, the coating may be dried without substantial drying
from spin-dry.
[0039] In another embodiment, the coating may be dried in block 406
after application of the coating in block 404. In such an
embodiment, the coating may be spun to achieve at least a partially
conformal coating distribution. In an embodiment, the coating may
optionally be spin dried. In block 408, the coating may be
optionally baked to further drive out any solvents, to cure the
coating, or to finalize or complete any reactions in the coating. A
solvent may be applied and the coating reflowed in block 410. The
coating may be dried after the reflow. The thickness of the coating
may optionally be measured in block 416 and a second coating
optionally applied in block 418.
[0040] The planarized coating may be baked in block 420. In an
embodiment, the coating may be processed further, for example, by
patterning and developing a photoresist coating, by forming a
post-passivation interconnect layer over a protective coating, or
the like.
[0041] Thus, in an embodiment, a method of forming a coating may
comprise applying a first coating to a substrate having a plurality
of topographical features, planarizing a top surface of the first
coating, and drying the coating after planarizing the top surface
of the first coating. The first coating may be applied over the
plurality of topographical features, and substantially liquid
during application. The first coating may optionally be a conformal
coating over topographical features of the substrate. The conformal
coating may be dried prior to planarizing the top surface of the
first coating and a solvent applied to the conformal coating, with
the top surface of the conformal coating being substantially planar
after application of the solvent. The coating may have a planar
surface prior to the drying the first coating, and the first
coating may be dried without substantial spin-drying by modifying
an environment of the first coating.
[0042] According to an embodiment, a system for applying a coating
may comprise a coating chamber with a platen configured to hold a
wafer and a coating nozzle configured to deliver a first coating to
the wafer. The coating chamber may be configured to dry the first
coating on the wafer with a substantially planar top surface and
without substantial spin drying. The platen may be configured to
spin the wafer at a first speed during delivery of the first
coating to the wafer and configured to spin the wafer at a second
speed during drying of the first coating. The platen may be further
configured to vibrate the wafer during application of the first
coating and during drying of the first coating. The coating chamber
may dry the first coating by controlling an environment contained
in the coating chamber by modifying at least one of a gas pressure,
a gas flow rate and a temperature. The first coating may be a
conformal coating conforming to topographical features on the
wafer. The coating chamber may be configured to dry the conformal
coating prior to, and to planarize the top surface of the conformal
coating after, drying the conformal coating by applying a solvent
to the conformal coating. A thickness monitor may be configured to
measure a thickness of the first coating, and the coating chamber
may apply a second coating on the planar top surface of the first
coating, with the second coating having a thickness depending on at
least the thickness of the first coating measured by the thickness
monitor.
[0043] Although embodiments of the present disclosure and their
advantages have been described in detail, it should be understood
that various changes, substitutions and alterations can be made
herein without departing from the spirit and scope of the
disclosure as defined by the appended claims. For example, it will
be readily understood by those skilled in the art that many of the
features, functions, processes, and materials described herein may
be varied while remaining within the scope of the present
disclosure. Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, and composition of matter, means,
methods or steps described in the specification. As one of ordinary
skill in the art will readily appreciate from the disclosure of the
present disclosure, processes, machines, manufacture, compositions
of matter, means, methods, or steps, presently existing or later to
be developed, that perform substantially the same function or
achieve substantially the same result as the corresponding
embodiments described herein may be utilized according to the
present disclosure. Accordingly, the appended claims are intended
to include within their scope such processes, machines,
manufacture, compositions of matter, means, methods, or steps.
* * * * *