U.S. patent application number 16/396424 was filed with the patent office on 2020-10-29 for light filter structure.
The applicant listed for this patent is VisEra Technologies Company Limited. Invention is credited to Yu-Jen CHEN.
Application Number | 20200343390 16/396424 |
Document ID | / |
Family ID | 1000004036773 |
Filed Date | 2020-10-29 |
United States Patent
Application |
20200343390 |
Kind Code |
A1 |
CHEN; Yu-Jen |
October 29, 2020 |
LIGHT FILTER STRUCTURE
Abstract
A light filter structure is provided. The light filter structure
includes a substrate having a plurality of photoelectric conversion
elements. The light filter structure also includes a first
metal-stacking layer disposed on the substrate. The light filter
structure further includes a graded layer disposed on the first
metal-stacking layer. The graded layer has a continuously or
non-continuously varied thickness. The light filter structure
includes a flatting layer disposed on the graded layer. The light
filter structure also includes a second metal-stacking layer
disposed on the flatting layer.
Inventors: |
CHEN; Yu-Jen; (Taoyuan City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VisEra Technologies Company Limited |
Hsin-Chu City |
|
TW |
|
|
Family ID: |
1000004036773 |
Appl. No.: |
16/396424 |
Filed: |
April 26, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 5/20 20130101; H01L
27/1446 20130101; G01J 3/0229 20130101; G01J 3/2803 20130101; H01L
31/02165 20130101; H01L 31/02164 20130101 |
International
Class: |
H01L 31/0216 20060101
H01L031/0216; H01L 27/144 20060101 H01L027/144; G02B 5/20 20060101
G02B005/20; G01J 3/02 20060101 G01J003/02; G01J 3/28 20060101
G01J003/28 |
Claims
1. A light filter structure, comprising: a substrate having a
plurality of photoelectric conversion elements; a first
metal-stacking layer disposed on the substrate; a graded layer
disposed on the first metal-stacking layer, wherein the graded
layer has a continuously or non-continuously varied thickness; a
flatting layer disposed on the graded layer; and a second
metal-stacking layer disposed on the flatting layer.
2. The light filter structure as claimed in claim 1, wherein a
refractive index of the graded layer is different from a refractive
index of the flatting layer.
3. The light filter structure as claimed in claim 1, wherein the
graded layer gradually thins from a center of the graded layer to a
periphery of the graded layer.
4. The light filter structure as claimed in claim 3, wherein a
refractive index of the flatting layer is less than a refractive
index of the graded layer.
5. The light filter structure as claimed in claim 3, wherein a
refractive index of the flatting layer is greater than a refractive
index of the graded layer.
6. The light filter structure as claimed in claim 1, wherein the
graded layer gradually thickens from a center of the graded layer
to a periphery of the graded layer.
7. The light filter structure as claimed in claim 6, wherein a
refractive index of the flatting layer is less than a refractive
index of the graded layer.
8. The light filter structure as claimed in claim 6, wherein a
refractive index of the flatting layer is greater than a refractive
index of the graded layer.
9. The light filter structure as claimed in claim 1, wherein the
first metal-stacking layer and the second metal-stacking layer each
comprises at least one metal layer and at least one adhesion layer
stacked with the at least one metal layer.
10. The light filter structure as claimed in claim 9, wherein a
material of the at least one metal layer comprises gold, copper,
aluminum, silver, or nickel.
11. The light filter structure as claimed in claim 9, wherein a
material of the at least one adhesion layers comprises titanium,
chromium, zinc oxide, or aluminium oxide.
12. The light filter structure as claimed in claim 9, wherein a
total number of the at least one metal layer and the at least one
adhesion layer in the first metal-stacking layer or a total number
of the at least one metal layer and the at least one adhesion layer
in the second metal-stacking layer is between 4 and 15.
13. The light filter structure as claimed in claim 1, wherein a
total thickness of the first metal-stacking layer, the graded
layer, the flatting layer and the second metal-stacking layer is
less than 3 .mu.m.
14. The light filter structure as claimed in claim 1, further
comprising: a light-shielding layer disposed on the second
metal-stacking layer, wherein the light-shielding layer comprises a
plurality of apertures.
15. The light filter structure as claimed in claim 14, wherein each
of the plurality of apertures corresponds to one of the plurality
of photoelectric conversion elements.
16. The light filter structure as claimed in claim 14, wherein a
width of each of the plurality of apertures in a direction parallel
with a top surface of the substrate is greater than 1 .mu.m, and
less than 150 .mu.m.
17. The light filter structure as claimed in claim 14, wherein each
of the plurality of apertures corresponds to at least two of the
plurality of photoelectric conversion elements.
18. The light filter structure as claimed in claim 14, wherein the
plurality of apertures forms a symmetrical pattern.
19. The light filter structure as claimed in claim 18, wherein the
plurality of apertures is arranged in concentric circles.
20. The light filter structure as claimed in claim 1, wherein a
material of the graded layer comprises zirconium dioxide, tantalum
pentoxide, niobium pentoxide, zinc sulfide, titanium dioxide,
indium tin oxide, stannic oxide, zinc oxide, calcium fluoride,
magnesium fluoride, lanthanum trifluoride, silicon dioxide,
aluminium oxide, or hafnium dioxide.
Description
BACKGROUND
Technical Field
[0001] Embodiments of the present disclosure relate to a light
filter structure. More specifically, the present disclosure relates
to a light filter structure that includes a graded layer.
Description of the Related Art
[0002] Light filters have been widely used in various devices, such
as spectrum meters, ambient light sensors, color sensors, image
sensors, spectral inspection devices, and so on. However,
traditional light filter structures may not satisfy demands in
every respect. For example, when a traditional light filter
structure is used as a narrow-band pass filter, it is usually very
thick. Moreover, the spectrum obtained from the traditional light
filter structure may have unexpected deformation due to oblique
incident-light. Furthermore, it is hard to reduce the size of the
traditional light filter structure to, for example, a few
micrometers to meet demand.
SUMMARY
[0003] In accordance with some embodiments of the present
disclosure, a light filter structure is provided. The light filter
structure includes a substrate having a plurality of photoelectric
conversion elements. The light filter structure also includes a
first metal-stacking layer disposed on the substrate. The light
filter structure further includes a graded layer disposed on the
first metal-stacking layer. The graded layer has a continuously or
non-continuously varied thickness. The light filter structure
includes a flatting layer disposed on the graded layer. The light
filter structure also includes a second metal-stacking layer
disposed on the flatting layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Aspects of the embodiments of the present disclosure may be
understood from the following detailed description when reading
with the accompanying figures. It should be noted that, in
accordance with the standard practice in the industry, various
features are not drawn to scale. In fact, the dimensions of the
various features may be arbitrarily increased or reduced for easy
and clear discussion.
[0005] FIG. 1 is a partial cross-sectional view illustrating a
light filter structure according to one embodiment of the present
disclosure.
[0006] FIG. 2 is a partial cross-sectional view illustrating a
light filter structure according to another embodiment of the
present disclosure.
[0007] FIG. 3 is a partial cross-sectional view illustrating a
light filter structure according to one embodiment of the present
disclosure.
[0008] FIG. 4 is a partial cross-sectional view illustrating a
light filter structure according to another embodiment of the
present disclosure.
[0009] FIG. 5 is a partial cross-sectional view illustrating a
light filter structure according to one embodiment of the present
disclosure.
[0010] FIG. 6 is a partial top view illustrating the apertures of
the light-shielding layer according to one embodiment of the
present disclosure.
DETAILED DESCRIPTION
[0011] The following disclosure provides many different
embodiments, or examples, for implementing different features of
the subject matter provided. Specific examples of components and
arrangements are described below to simplify the present
disclosure. These are, of course, merely examples and are not
intended to be limiting. For example, the formation of a first
feature over or on a second feature in the description that follows
may include embodiments in which the first and second features are
formed in direct contact, and may also include embodiments in which
additional features may be formed between the first and second
features, such that the first and second features may not be in
direct contact.
[0012] It should be understood that additional steps may be
implemented before, during, or after the illustrated methods, and
some steps might be replaced or omitted in other embodiments of the
illustrated methods.
[0013] Furthermore, spatially relative terms, such as "beneath,"
"below," "lower," "on," "above," "upper" and the like, may be used
herein for ease of description to describe one element or feature's
relationship to another element(s) or feature(s) as illustrated in
the figures. The spatially relative terms are intended to encompass
different orientations of the device in use or operation in
addition to the orientation depicted in the figures. The apparatus
may be otherwise oriented (rotated 45 degrees or at other
orientations) and the spatially relative descriptors used herein
may likewise be interpreted accordingly.
[0014] In the present disclosure, the terms "about" and
"substantially" typically mean +/-20% of the stated value, more
typically +/-10% of the stated value, more typically +/-5% of the
stated value, more typically +/-3% of the stated value, more
typically +/-2% of the stated value, more typically +/-1% of the
stated value and even more typically +/-0.5% of the stated value.
The stated value of the present disclosure is an approximate value.
That is, when there is no specific description of the terms "about"
and "substantially", the stated value still includes the meaning of
"about" or "substantially".
[0015] It should be understood that, although the terms "first,"
"second," "third," etc. can be used herein to describe various
elements, components, regions, layers and/or sections, these
elements, components, regions, layers and/or sections should not be
limited by these terms. These terms are only used to distinguish
one element, component, region, layer or section from another
region, layer or section. Thus, a first element, component, region,
layer or section discussed below could be termed a second element,
component, region, layer or section without departing from the
teachings of the present disclosure.
[0016] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which this
disclosure belongs. It should be understood that terms such as
those defined in commonly used dictionaries should be interpreted
as having a meaning that is consistent with their meaning in the
context of the relevant art and will not be interpreted in an
idealized or overly formal sense unless expressly so defined in the
embodiments of the present disclosure.
[0017] FIG. 1 is a partial cross-sectional view illustrating a
light filter structure 100 according to one embodiment of the
present disclosure. It should be noted that not all components of
the light filter structure 100 are shown in FIG. 1, for the sake of
brevity.
[0018] Referring to FIG. 1, the light filter structure 100 includes
a substrate 10. In some embodiments, the material of the substrate
10 may include an elemental semiconductor (e.g., silicon,
germanium), a compound semiconductor (e.g., tantalum carbide (TaC),
gallium arsenide (GaAs), indium arsenide (InAs) or indium phosphide
(InP)), an alloy semiconductor (e.g., silicon germanium (SiGe),
silicon germanium carbide (SiGeC), gallium arsenic phosphide
(GaAsP) or gallium indium phosphide (GaInP)), any other applicable
semiconductor, or a combination thereof, but the present disclosure
is not limited thereto.
[0019] In some embodiments, the substrate 10 may be a
semiconductor-on-insulator (SOI) substrate. The
semiconductor-on-insulator substrate may include a bottom
substrate, a buried oxide layer disposed on the bottom substrate,
and a semiconductor layer disposed on the buried oxide layer. In
some embodiments, the substrate 10 may be a semiconductor wafer
(e.g., a silicon wafer, or any other applicable semiconductor
wafer). In some embodiments, the material of the substrate 10 may
include, but is not limited to, at least one of the following:
ceramic, glass, polyimide (PI), liquid-crystal polymer (LCP),
polycarbonate (PC), polypropylene (PP), polyethylene terephthalate
(PET) (and other plastic), a polymer material, or a combination
thereof.
[0020] In some embodiments, the substrate 10 may include various
conductive features (e.g., conductive lines or vias). For example,
the conductive features may be made of aluminum (Al), copper (Cu),
tungsten (W), an alloy thereof, any other applicable conductive
material, or a combination thereof, but the present disclosure is
not limited thereto.
[0021] As shown in FIG. 1, the substrate 10 may have a plurality of
photoelectric conversion elements 12. In some embodiments, the
photoelectric conversion elements 12 may be formed by a process
such as an ion implantation process and/or a diffusion process. For
example, the photoelectric conversion elements 12 may be configured
to form transistors, photodiodes, PIN diodes and/or light-emitting
diodes, but the present disclosure is not limited thereto.
[0022] Referring to FIG. 1, the light filter structure 100 includes
a first metal-stacking layer 20 disposed on the substrate 10. In
this embodiment, the first metal-stacking layer 20 may include at
least one metal layer 21 and at least one adhesion layer 23 stacked
with the metal layer 21. That is, the metal layers 21 and the
adhesion layer 23 may be alternately stacked with each other, for
example. In FIG. 1, the first metal-stacking layer 20 includes two
metal layers 21 and one adhesion layer 23 disposed between the two
metal layers 21. In some embodiments, the total number of metal
layers 21 and adhesion layers 23 in the first metal-stacking layer
20 may be between 4 and 15. However, the number of metal layers 21
and the number of adhesion layers 23 are not limited thereto.
[0023] In some embodiments, the material of the metal layer 21 may
include gold (Au), copper (Cu), aluminum (Al), silver (Ag), nickel
(Ni), or any other applicable metal, but the present disclosure is
not limited thereto. In some embodiments, the material of the
adhesion layer 23 may include titanium (Ti), chromium (Cr), zinc
oxide (ZnO), aluminium oxide (Al.sub.2O.sub.3), or any other
applicable material, but the present disclosure is not limited
thereto. In some embodiments, the metal layer 21 and the adhesion
layer 23 may be formed by a chemical vapor deposition process, an
atomic layer deposition process, a physical vapor deposition
process, or another suitable method, but the present disclosure is
not limited thereto. For example, the chemical vapor deposition
process may be low-pressure chemical vapor deposition,
low-temperature chemical vapor deposition, rapid thermal chemical
vapor deposition, or plasma-enhanced chemical vapor deposition. For
example, the physical vapor deposition process may be a vacuum
evaporation process or a sputtering process.
[0024] Referring to FIG. 1, the light filter structure 100 includes
a graded layer 30 disposed on the first metal-stacking layer 20. As
shown in FIG. 1, the graded layer 30 may have a continuously varied
thickness in this embodiment, but the present disclosure is not
limited thereto. In other embodiments, the graded layer 30 may also
have a non-continuously varied thickness (e.g., the graded layer 33
shown in following FIG. 5).
[0025] In some embodiments, the material of the graded layer 30 may
include dielectric materials. For example, the material of the
graded layer 30 may include zirconium dioxide (ZrO.sub.2), tantalum
pentoxide (Ta.sub.2O.sub.5), niobium pentoxide (Nb.sub.2O.sub.5),
zinc sulfide (ZnS), titanium dioxide (TiO.sub.2), indium tin oxide
(ITO), Tin oxide (SnO.sub.2), zinc oxide (ZnO), calcium fluoride
(CaF.sub.2), magnesium fluoride (MgF.sub.2), lanthanum trifluoride
(LaF.sub.3), silicon dioxide (SiO.sub.2), aluminium oxide
(Al.sub.2O.sub.3), hafnium dioxide (HfO.sub.2), or any other
applicable material, but the present disclosure is not limited
thereto.
[0026] In some embodiments, the graded layer 30 may be formed by a
chemical vapor deposition process, an atomic layer deposition
process, a physical vapor deposition process, or another suitable
method, but the present disclosure is not limited thereto. For
example, the chemical vapor deposition process may be low-pressure
chemical vapor deposition, low-temperature chemical vapor
deposition, rapid thermal chemical vapor deposition, or
plasma-enhanced chemical vapor deposition. Moreover, the graded
layer 30 may be deposited on the first metal-stacking layer 20 by
using a specific mask to form the graded layer 30 having a
continuously varied thickness.
[0027] In this embodiment, the graded layer 30 may gradually thin
from the center C of the graded layer 30 to the periphery P of the
graded layer 30. That is, the thickness of the center C of the
graded layer 30 may be the maximum thickness of the graded layer
30, while the thickness of the periphery P of the graded layer 30
may be the minimum thickness of the graded layer 30, but the
present disclosure is not limited thereto.
[0028] Referring to FIG. 1, the light filter structure 100 includes
a flatting layer 40 disposed on the graded layer 30. In this
embodiment, the flatting layer 40 is a transparent layer, and the
material of the flatting layer 40 may include a transparent
photoresist, polyimide, epoxy resin, any other applicable material,
or a combination thereof, but the present disclosure is not limited
thereto.
[0029] In some embodiments, the material of the flatting layer 40
may include a light curing material, a thermal curing material, or
a combination thereof. For example, a spin-on coating process may
be performed to coat the transparent material on the graded layer
30, and then a planarization process may be performed to form the
flatting layer 40, but the present disclosure is not limited
thereto. For example, the planarization process may include a
chemical mechanical polishing (CMP) process, a grinding process, an
etching back process, any other applicable process, or a
combination thereof.
[0030] In some embodiments, the refractive index of the graded
layer 30 may be different from the refractive index of the flatting
layer 40. For example, the refractive index of the flatting layer
40 may be less than the refractive index of the graded layer 30 in
FIG. 1, but the present disclosure is not limited thereto.
[0031] Moreover, in this embodiment, the total thickness T1 of the
graded layer 30 and the flatting layer 40 from the center of the
light filter 100 to the periphery of the light filter 100 may be
kept substantially constant, and the volume ratio of the flatting
layer 40 to the graded layer 30 may decide the equivalent
refractive index at different positions.
[0032] Referring to FIG. 1, the light filter structure 100 includes
a second metal-stacking layer 50 disposed on the flatting layer 40.
Similarly, the second metal-stacking layer 50 may include at least
one metal layer 51 and at least one adhesion layer 53 stacked with
the metal layer 51. That is, the metal layers 51 and the adhesion
layers 53 may be alternately stacked with each other, for example.
In FIG. 1, the second metal-stacking layer 50 includes two metal
layers 51 and two adhesion layers 53 alternately arranged with each
other. In some embodiments, the total number of metal layers 51 and
adhesion layers 53 in the second metal-stacking layer 50 may be
between 4 and 15. However, the number of metal layers 51 and the
number of adhesion layers 53 are not limited thereto.
[0033] In some embodiments, the material of the metal layer 51 may
include gold (Au), copper (Cu), aluminum (Al), silver (Ag), nickel
(Ni), or any other applicable metal, but the present disclosure is
not limited thereto. In some embodiments, the material of the
adhesion layer 53 may include titanium (Ti), chromium (Cr), zinc
oxide (ZnO), aluminium oxide (Al.sub.2O.sub.3), or any other
applicable material, but the present disclosure is not limited
thereto. In some embodiments, the metal layer 51 and the adhesion
layer 53 may be formed by a chemical vapor deposition process, an
atomic layer deposition process, a physical vapor deposition
process, or another suitable method, but the present disclosure is
not limited thereto. For example, the chemical vapor deposition
process may be low-pressure chemical vapor deposition,
low-temperature chemical vapor deposition, rapid thermal chemical
vapor deposition, or plasma-enhanced chemical vapor deposition. For
example, the physical vapor deposition process may be a vacuum
evaporation process or a sputtering process.
[0034] In some embodiments, the first metal-stacking layer 20 may
include at least one metal layer 21, the second metal-stacking
layer 50 may include at least one metal layer 51, and the first
metal-stacking layer 20 and the second metal-stacking layer 50 may
act as high-reflectors of Fabry-Perot resonator; furthermore, the
total thickness T2 of the first metal-stacking layer 20, the graded
layer 30, the flatting layer 40 and the second metal-stacking layer
50 may be thin (e.g., less than 3 .mu.m). Therefore, the light
filter structure 100 may be low angle dependency. That is, the
deformation of the spectrum due to oblique incident-light
transmitted to the light filter structure 100 may be reduced. For
example, the blue light shift during 300 nm to 900 nm on Automated
Optical Inspection (AOI) 30.degree. may be less than or equal to 15
nm.
[0035] In the embodiment shown in FIG. 1, when the refractive index
of the flatting layer 40 is less than the refractive index of the
graded layer 30 (e.g., the refractive index of the flatting layer
40 is 1.5 and the refractive index of the graded layer 30 is 2.5),
the closer a photoelectric conversion element 12 is to the center
of the light filter 100, the longer the wavelength of the light
transmitted to the photoelectric conversion element 12 is. For
example, the photoelectric conversion element 12C is close to the
center of the light filter 100, so that the red light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 100, so that the blue light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0036] In the embodiment shown in FIG. 1, when the refractive index
of the flatting layer 40 is greater than the refractive index of
the graded layer 30 (e.g., the refractive index of the flatting
layer 40 is 2.5 and the refractive index of the graded layer 30 is
1.5), the closer a photoelectric conversion element 12 is to the
center of the light filter 100, the shorter the wavelength of the
light transmitted to the photoelectric conversion element 12 is.
For example, the photoelectric conversion element 12C is close to
the center of the light filter 100, so that the blue light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 100, so that the red light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0037] FIG. 2 is a partial cross-sectional view illustrating a
light filter structure 101 according to another embodiment of the
present disclosure. It should be noted that not all components of
the light filter structure 101 are shown in FIG. 2, for the sake of
brevity.
[0038] Referring to FIG. 2, the light filter structure 101 includes
a substrate 10. Similarly, the substrate 10 may have a plurality of
photoelectric conversion elements 12. The light filter structure
101 includes a first metal-stacking layer 20 disposed on the
substrate 10. The light filter structure 101 also includes a graded
layer 31 disposed on the first metal-stacking layer 20 and a
flatting layer 40 disposed on the graded layer 31. The light filter
structure 101 further includes a second metal-stacking layer 50
disposed on the flatting layer 40.
[0039] The difference from the light filter structure 100 shown in
FIG. 1 may include that the graded layer 31 of the light filter
structure 102 shown in FIG. 2 may gradually thicken from the center
C' of the graded layer 31 to the periphery P' of the graded layer
31. That is, the thickness of the center C' of the graded layer 31
may be the minimum thickness of the graded layer 31, while the
thickness of the periphery P' of the graded layer 31 may be the
maximum thickness of the graded layer 31, but the present
disclosure is not limited thereto.
[0040] In some embodiments, the material of the graded layer 31
shown in FIG. 2 may be substantially the same as the material of
the graded layer 30 shown in FIG. 1, but the present disclosure is
not limited thereto. Similarly, the refractive index of the graded
layer 31 may be different from the refractive index of the flatting
layer 40. For example, the refractive index of the flatting layer
40 may be less than the refractive index of the graded layer 31 in
FIG. 2, but the present disclosure is not limited thereto.
[0041] Moreover, in this embodiment, the total thickness T3 of the
graded layer 31 and the flatting layer 40 from the center of the
light filter 101 to the periphery of the light filter 101 may be
kept substantially constant, and the volume ratio of the flatting
layer 40 to the graded layer 31 may decide the equivalent
refractive index at different positions.
[0042] In some embodiments, the first metal-stacking layer 20 may
include at least one metal layer 21, the second metal-stacking
layer 50 may include at least one metal layer 51, and the first
metal-stacking layer 20 and the second metal-stacking layer 50 may
act as high-reflectors of Fabry-Perot resonator; furthermore, the
total thickness T4 of the first metal-stacking layer 20, the graded
layer 31, the flatting layer 40 and the second metal-stacking layer
50 may be thin (e.g., less than 3 .mu.m). Therefore, the light
filter structure 101 may be low angle dependency. That is, the
deformation of the spectrum due to oblique incident-light
transmitted to the light filter structure 101 may be reduced.
[0043] In the embodiment shown in FIG. 2, when the refractive index
of the flatting layer 40 is less than the refractive index of the
graded layer 31 (e.g., the refractive index of the flatting layer
40 is 1.5 and the refractive index of the graded layer 31 is 2.5),
the closer a photoelectric conversion element 12 is to the center
of the light filter 101, the shorter the wavelength of the light
transmitted to the photoelectric conversion element 12 is. For
example, the photoelectric conversion element 12C is close to the
center of the light filter 101, so that the blue light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 101, so that the red light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0044] In the embodiment shown in FIG. 2, when the refractive index
of the flatting layer 40 is greater than the refractive index of
the graded layer 31 (e.g., the refractive index of the flatting
layer 40 is 2.5 and the refractive index of the graded layer 31 is
1.5), the closer a photoelectric conversion element 12 is to the
center of the light filter 101, the longer the wavelength of the
light transmitted to the photoelectric conversion element 12 is.
For example, the photoelectric conversion element 12C is close to
the center of the light filter 101, so that the red light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 101, so that the blue light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0045] FIG. 3 is a partial cross-sectional view illustrating a
light filter structure 102 according to one embodiment of the
present disclosure. It should be noted that not all components of
the light filter structure 102 are shown in FIG. 3, for the sake of
brevity.
[0046] Referring to FIG. 3, the light filter structure 102 includes
a substrate 10. Similarly, the substrate 10 may have a plurality of
photoelectric conversion elements 12. The light filter structure
102 includes a first metal-stacking layer 20 disposed on the
substrate 10. The light filter structure 102 also includes a graded
layer 30 disposed on the first metal-stacking layer 20 and a
flatting layer 40 disposed on the graded layer 30. The light filter
structure 102 further includes a second metal-stacking layer 50
disposed on the flatting layer 40.
[0047] In this embodiment, the light filter structure 102 may
further include a light-shielding layer 60 disposed on the second
metal-stacking layer 50. As shown in FIG. 3, the light-shielding
layer 60 may include a plurality of apertures 60a. In some
embodiments, each of the apertures 60a may correspond to one of the
photoelectric conversion elements 12, but the present disclosure is
not limited thereto.
[0048] In some embodiments, the material of the light-shielding
layer 60 may include photoresist (e.g., black photoresist, or other
applicable photoresist which is not transparent to specific
wavelength), ink (e.g., black ink, or other applicable ink which is
not transparent to specific wavelength), molding compound (e.g.,
black molding compound, or other applicable molding compound which
is not transparent to specific wavelength), solder mask (e.g.,
black solder mask, or other applicable solder mask which is not
transparent to specific wavelength), (black-)epoxy polymer, any
other applicable material, or a combination thereof. In some
embodiments, the material of the light-shielding layer 60 may
include a light curing material, a thermal curing material, or a
combination thereof, but the present disclosure is not limited
thereto.
[0049] In some embodiments, the light-shielding layer 60 may be
formed on the second metal-stacking layer 50 by a coating process
or a patterning process. In some embodiments, the patterning
process may include soft baking, mask aligning, exposure,
post-exposure baking, developing, rinsing, drying, any other
applicable process, or a combination thereof, but the present
disclosure is not limited thereto.
[0050] As shown in FIG. 3, the width W of each of the apertures 60a
in a direction D1 parallel with a top surface 10T of the substrate
10 may be greater than 1 .mu.m, and less than 150 .mu.m, but the
present disclosure is not limited thereto. When the light filter
structure 102 is used in the spectral inspection device, the
spectral resolution may be determined by the sizes of the apertures
60a. That is, the spectral resolution may be enhanced by adjusting
the sizes of the apertures 60a of the light-shielding layer 60.
[0051] FIG. 4 is a partial cross-sectional view illustrating a
light filter structure 103 according to another embodiment of the
present disclosure. It should be noted that not all components of
the light filter structure 103 are shown in FIG. 4, for the sake of
brevity.
[0052] Referring to FIG. 4, the light filter structure 103 includes
a substrate 10. Similarly, the substrate 10 may have a plurality of
photoelectric conversion elements 12. The light filter structure
103 includes a first metal-stacking layer 20 disposed on the
substrate 10. The light filter structure 103 also includes a graded
layer 30 disposed on the first metal-stacking layer 20 and a
flatting layer 40 disposed on the graded layer 30. The light filter
structure 103 further includes a second metal-stacking layer 50
disposed on the flatting layer 40 and a light-shielding layer 61
disposed on the second metal-stacking layer 50.
[0053] As shown in FIG. 4, the light-shielding layer 61 may include
a plurality of apertures 61a. In this embodiment, each of the
apertures 61a may correspond to two of the photoelectric conversion
elements 12, but the present disclosure is not limited thereto. In
other embodiments, each of the apertures 61a may correspond to more
than two of the photoelectric conversion elements 12.
[0054] In some embodiments, the material of the light-shielding
layer 61 shown in FIG. 4 may be substantially the same as the
material of the light-shielding layer 60 shown in FIG. 3, but the
present disclosure is not limited thereto. In some embodiments, the
light-shielding layer 61 may be formed on the second metal-stacking
layer 50 by a coating process or a patterning process. In some
embodiments, the patterning process may include soft baking, mask
aligning, exposure, post-exposure baking, developing, rinsing,
drying, any other applicable process, or a combination thereof, but
the present disclosure is not limited thereto.
[0055] Similarly, when the light filter structure 103 is used in
the spectral inspection device, the spectral resolution may be
determined by the sizes of the apertures 61a. That is, the spectral
resolution may be enhanced by adjusting the sizes of the apertures
61a.
[0056] FIG. 5 is a partial cross-sectional view illustrating a
light filter structure 104 according to one embodiment of the
present disclosure. It should be noted that not all components of
the light filter structure 104 are shown in FIG. 5, for the sake of
brevity.
[0057] Referring to FIG. 5, the light filter structure 104 includes
a substrate 10. Similarly, the substrate 10 may have a plurality of
photoelectric conversion elements 12. The light filter structure
104 includes a first metal-stacking layer 20 disposed on the
substrate 10. The light filter structure 104 also includes a graded
layer 33 disposed on the first metal-stacking layer 20 and a
flatting layer 40 disposed on the graded layer 33. The light filter
structure 104 further includes a second metal-stacking layer 50
disposed on the flatting layer 40 and a light-shielding layer 60
disposed on the second metal-stacking layer 50. As shown in FIG. 5,
the light-shielding layer 60 may include a plurality of apertures
60a. In this embodiment, each of the apertures 60a may correspond
to one of the photoelectric conversion elements 12, but the present
disclosure is not limited thereto.
[0058] The difference from the light filter structure 102 shown in
FIG. 3 may include that the graded layer 33 of the light filter
structure 104 shown in FIG. 5 may have a non-continuously varied
thickness. For example, the graded layer 33 shown in FIG. 5 may
have a step shape, but the present disclosure is not limited
thereto.
[0059] In some embodiments, the material of the graded layer 33
shown in FIG. 5 may be substantially the same as the material of
the graded layer 33 shown in FIGS. 1, 3 and 4, but the present
disclosure is not limited thereto. In some embodiments, the graded
layer 33 may be formed by a chemical vapor deposition process, an
atomic layer deposition process, a physical vapor deposition
process, or another suitable method, but the present disclosure is
not limited thereto. For example, the chemical vapor deposition
process may be low-pressure chemical vapor deposition,
low-temperature chemical vapor deposition, rapid thermal chemical
vapor deposition, or plasma-enhanced chemical vapor deposition.
[0060] Similarly, the graded layer 33 may thin from the center C''
of the graded layer 33 to the periphery P'' of the graded layer 33.
That is, the thickness of the center C'' of the graded layer 33 may
be the maximum thickness of the graded layer 33, while the
thickness of the periphery P'' of the graded layer 33 may be the
minimum thickness of the graded layer 33, but the present
disclosure is not limited thereto.
[0061] In the embodiment shown in FIG. 5, when the refractive index
of the flatting layer 40 is less than the refractive index of the
graded layer 33 (e.g., the refractive index of the flatting layer
40 is 1.5 and the refractive index of the graded layer 33 is 2.5),
the closer a photoelectric conversion element 12 is to the center
of the light filter 104, the longer the wavelength of the light
transmitted to the photoelectric conversion element 12 is. For
example, the photoelectric conversion element 12C is close to the
center of the light filter 104, so that the red light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 104, so that the blue light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0062] In the embodiment shown in FIG. 5, when the refractive index
of the flatting layer 40 is greater than the refractive index of
the graded layer 33 (e.g., the refractive index of the flatting
layer 40 is 2.5 and the refractive index of the graded layer 33 is
1.5), the closer a photoelectric conversion element 12 is to the
center of the light filter 104, the shorter the wavelength of the
light transmitted to the photoelectric conversion element 12 is.
For example, the photoelectric conversion element 12C is close to
the center of the light filter 104, so that the blue light is
transmitted to the photoelectric conversion element 12C; the
photoelectric conversion element 12P is close to the periphery of
the light filter 104, so that the red light is transmitted to the
photoelectric conversion element 12C, but the present disclosure is
not limited thereto.
[0063] FIG. 6 is a partial top view illustrating the apertures 60a
of the light-shielding layer 60 according to one embodiment of the
present disclosure. It should be noted that a partial top view
illustrating apertures 61a of the light-shielding layer 61
according to one embodiment of the present disclosure may be
similar to FIG. 6.
[0064] In some embodiments, the apertures 60a of the
light-shielding layer 60 may forms a symmetrical pattern. For
example, the apertures 60a of the light-shielding layer 60 may be
arranged in concentric circles as shown in FIG. 6, but the present
disclosure is not limited thereto.
[0065] In summary, when the light filter structure of the
embodiment according to the present disclosure is used as a
narrow-band pass filter, it may have small thickness to meet
demand. Moreover, the light filter structure of the embodiment
according to the present disclosure may be low angle dependency.
Therefore, the deformation of the spectrum due to oblique
incident-light transmitted to the light filter structure of the
embodiments according to the present disclosure may be reduced.
Furthermore, when the light filter structure of some embodiments
according to the present disclosure is used in the spectral
inspection device, the spectral resolution may be enhanced by
adjusting the sizes of the apertures of the light-shielding
layer.
[0066] The foregoing outlines features of several embodiments so
that those skilled in the art may better understand the aspects of
the present disclosure. Those skilled in the art should appreciate
that they may readily use the present disclosure as a basis for
designing or modifying other processes and structures for carrying
out the same purposes and/or achieving the same advantages of the
embodiments introduced herein. Those skilled in the art should also
realize that such equivalent constructions do not depart from the
spirit and scope of the present disclosure, and that they may make
various changes, substitutions, and alterations herein without
departing from the spirit and scope of the present disclosure.
Therefore, the scope of protection should be determined by the
claims. In addition, although some embodiments of the present
disclosure are disclosed above, they are not intended to limit the
scope of the present disclosure.
[0067] Reference throughout this specification to features,
advantages, or similar language does not imply that all of the
features and advantages that may be realized with the present
disclosure should be or are in any single embodiment of the
disclosure. Rather, language referring to the features and
advantages is understood to mean that a specific feature,
advantage, or characteristic described in connection with an
embodiment is included in at least one embodiment of the present
disclosure. Thus, discussions of the features and advantages, and
similar language, throughout this specification may, but do not
necessarily, refer to the same embodiment.
[0068] Furthermore, the described features, advantages, and
characteristics of the disclosure may be combined in any suitable
manner in one or more embodiments. One skilled in the relevant art
will recognize, in light of the description herein, that the
disclosure can be practiced without one or more of the specific
features or advantages of a particular embodiment. In other
instances, additional features and advantages may be recognized in
certain embodiments that may not be present in all embodiments of
the disclosure.
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