U.S. patent application number 14/996037 was filed with the patent office on 2016-07-21 for optical sensor with light-guiding feature and method for preparing the same.
The applicant listed for this patent is Personal Genomics, Inc.. Invention is credited to Coming CHEN, Yuan-Che LEE, Teng-Chien YU.
Application Number | 20160211390 14/996037 |
Document ID | / |
Family ID | 55177751 |
Filed Date | 2016-07-21 |
United States Patent
Application |
20160211390 |
Kind Code |
A1 |
CHEN; Coming ; et
al. |
July 21, 2016 |
Optical Sensor with Light-Guiding Feature and Method for Preparing
the Same
Abstract
An optical sensor includes a semiconductive layer having an
electrical circuit area and an optical sensing area, a
sample-holding portion over the optical sensing area, a
light-guiding structure between the sample-holding portion and the
optical sensing area, and an electrical interconnect structure over
the electrical circuit area. The electrical interconnect structure
is integrally formed with the light-guiding structure, and the
light-guiding structure is configured to direct an emitting light
from the sample-holding portion to the optical sensing area.
Inventors: |
CHEN; Coming; (Taoyuan City,
TW) ; YU; Teng-Chien; (Hsinchu City, TW) ;
LEE; Yuan-Che; (Taichung City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Personal Genomics, Inc. |
Grand Cayman |
|
KY |
|
|
Family ID: |
55177751 |
Appl. No.: |
14/996037 |
Filed: |
January 14, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62104340 |
Jan 16, 2015 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01N 2201/0642 20130101;
G01N 21/0303 20130101; G01N 21/6454 20130101; H01L 31/02327
20130101; H01L 31/02005 20130101; Y02E 10/50 20130101; G01N 21/7703
20130101; G01N 21/648 20130101; G01N 2021/7786 20130101; G02B
6/4214 20130101; G01N 2021/7753 20130101 |
International
Class: |
H01L 31/0232 20060101
H01L031/0232; H01L 31/02 20060101 H01L031/02; G01N 21/03 20060101
G01N021/03 |
Claims
1. An optical sensor, comprising: a semiconductive layer comprising
an electrical circuit area and an optical sensing area; a
sample-holding portion over the optical sensing area; a
light-guiding structure between the sample-holding portion and the
optical sensing area; and an electrical interconnect structure over
the electrical circuit area; wherein the electrical interconnect
structure is integrally formed with the light-guiding structure,
and the light-guiding structure is configured to direct an emitting
light from the sample-holding portion to the optical sensing
area.
2. The optical sensor of claim 1, wherein the electrical
interconnect structure comprises at least one electrical contact
over the electrical circuit area, and the light-guiding structure
comprises at least one first light-guiding part over the optical
sensing area.
3. The optical sensor of claim 2, wherein the semiconductive layer
has a horizontal upper surface, and the at least one electrical
contact and the at least one first light-guiding part extend
substantially in a same horizontal plane, which is in parallel to
and above the horizontal upper surface.
4. The optical sensor of claim 2, wherein the light-guiding
structure comprises a plurality of first light-guiding parts
arranged in a ring.
5. The optical sensor of claim 2, wherein the at least one first
light-guiding part is a ring-shaped part.
6. The optical sensor of claim 2, wherein the electrical
interconnect structure comprises at least one electrical via over
the at least one electrical contact, and the light-guiding
structure comprises at least one second light-guiding part over the
at least one first light-guiding part.
7. The optical sensor of claim 6, wherein the semiconductive layer
has a horizontal upper surface, and the at least one electrical via
and the at least one second light-guiding part extend substantially
in a same horizontal plane, which is in parallel to and above the
horizontal upper surface.
8. The optical sensor of claim 6, wherein the light-guiding
structure comprises a plurality of second light-guiding parts
arranged in a ring.
9. The optical sensor of claim 6, wherein the at least one second
light-guiding part is a ring-shaped part.
10. The optical sensor of claim 1, wherein the light-guiding
structure extends from a horizontal upper surface of the
semiconductive layer.
11. The optical sensor of claim 1, wherein the light-guiding
structure comprises an inner light-guiding bar in a first layer
over the semiconductive layer and an outer light-guiding bar in a
second layer over the semiconductive layer.
12. The optical sensor of claim 1, wherein a width of the
light-guiding structure is larger in an upper region close to the
sample-holding portion than that in a bottom region close to the
light-sensing region.
13. The optical sensor of claim 1, wherein a width of the
light-guiding structure is larger in a bottom region close to the
light-sensing region than that in the upper region close to the
sample-holding portion.
14. An optical sensor, comprising: a semiconductive layer
comprising an electrical circuit area and an optical sensing area;
a sample-holding portion over the optical sensing area; at least
one electrical contact over the electrical circuit area; and at
least one first light-guiding part configured to direct an emitting
light from the sample-holding portion to the optical sensing area;
wherein the semiconductive layer has a horizontal upper surface,
the at least one first light-guiding part is between the
sample-holding portion and the optical sensing area, and the at
least one electrical contact and the at least one first
light-guiding part extend substantially in a same horizontal plane,
which is in parallel to and above the horizontal upper surface.
15. The optical sensor of claim 14, wherein the at least one
electrical contact is integrally formed with the at least one first
light-guiding part.
16. An optical sensor, comprising: a semiconductive layer
comprising an optical sensing area; a sample-holding portion over
the optical sensing area; and a light-guiding structure configured
to direct an emitting light from the sample-holding portion to the
optical sensing area; wherein the light-guiding structure comprises
at least one light-guiding spacer extending from a horizontal upper
surface of the semiconductive layer, and the light-guiding
structure has a tapering top end near the sample-holding
portion.
17. The optical sensor of claim 16, wherein the light-guiding
structure comprises a plurality of light-guiding spacers arranged
in a ring.
18. The optical sensor of claim 16, wherein the light-guiding
structure comprises a ring-shaped guiding part.
19. The optical sensor of claim 16, comprising a plurality of
dielectric layers over the optical sensing area, wherein the at
least one light-guiding spacer extends through the plurality of
dielectric layers.
20. The optical sensor of claim 16, wherein the light-guiding
structure has a sidewall tilted with respect to the semiconductive
layer, and an included angle between the horizontal upper surface
of the semiconductive layer and the sidewall is about 60 degrees to
89.5 degrees.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to an optical sensor with a
light-guiding feature and a method for preparing the same.
DISCUSSION OF THE BACKGROUND
[0002] Optical sensors are widely used in various imaging
applications and products, such as cameras, scanners, photocopiers
and the like. Optical sensors used in various fields of technology
are designed for different purposes.
[0003] To improve performance and reduce size of optical sensors,
various designs for optical sensors are employed. One way to
evaluate the performance is by measuring the quantum efficiency of
an optical sensor. Quantum efficiency is a percentage of photons
hitting the optical sensor that produce charge carriers. It is a
measurement of the optical sensor's electrical sensitivity to
light.
[0004] This "Discussion of the Background" section is provided for
background information only. The statements in this "Discussion of
the Background" are not an admission that the subject matter
disclosed in this "Discussion of the Background" section
constitutes prior art to the present disclosure, and no part of
this "Discussion of the Background" section may be used as an
admission that any part of this application, including this
"Discussion of the Background" section, constitutes prior art to
the present disclosure.
SUMMARY
[0005] One aspect of the present disclosure provides an optical
sensor with a light-guiding feature and a method for preparing the
same.
[0006] An optical sensor, according to this aspect of the present
disclosure, comprises a semiconductive layer comprising an
electrical circuit area and an optical sensing area, a
sample-holding portion over the optical sensing area, a
light-guiding structure between the sample-holding portion and the
optical sensing area, and an electrical interconnect structure over
the electrical circuit area, wherein the electrical interconnect
structure is integrally formed with the light-guiding structure,
and the light-guiding structure is configured to direct an emitting
light from the sample-holding portion to the optical sensing
area.
[0007] In some embodiments, the electrical interconnect structure
comprises at least one electrical contact over the electrical
circuit area, and the light-guiding structure comprises at least
one first light-guiding part over the optical sensing area.
[0008] In some embodiments, the semiconductive layer has a
horizontal upper surface, and the at least one electrical contact
and the at least one first light-guiding part extend substantially
in a same horizontal plane, which is in parallel to and above the
horizontal upper surface.
[0009] In some embodiments, the light-guiding structure comprises a
plurality of first light-guiding parts arranged in a ring.
[0010] In some embodiments, the at least one first light-guiding
part is a ring-shaped part.
[0011] In some embodiments, the electrical interconnect structure
comprises at least one electrical via over the at least one
electrical contact, and the light-guiding structure comprises at
least one second light-guiding part over the at least one first
light-guiding part.
[0012] In some embodiments, the semiconductive layer has a
horizontal upper surface, and the at least one electrical via and
the at least one second light-guiding part extend substantially in
a same horizontal plane, which is in parallel to and above the
horizontal upper surface.
[0013] In some embodiments, the light-guiding structure comprises a
plurality of second light-guiding parts arranged in a ring.
[0014] In some embodiments, the at least one second light-guiding
part is a ring-shaped part.
[0015] In some embodiments, the light-guiding structure extends
from a horizontal upper surface of the semiconductive layer.
[0016] In some embodiments, the light-guiding structure comprises
an inner light-guiding bar in a first layer over the semiconductive
layer and an outer light-guiding bar in a second layer over the
semiconductive layer.
[0017] In some embodiments, a width of the light-guiding structure
is larger in an upper region close to the sample-holding portion
than that in a bottom region close to the light-sensing region.
[0018] In some embodiments, a width of the light-guiding structure
is larger in a bottom region close to the light-sensing region than
that in the upper region close to the sample-holding portion.
[0019] An optical sensor, according to another aspect of the
present disclosure, comprises a semiconductive layer comprising an
electrical circuit area and an optical sensing area, a
sample-holding portion over the optical sensing area, at least one
electrical contact over the electrical circuit area, and at least
one first light-guiding part configured to direct an emitting light
from the sample-holding portion to the optical sensing area,
wherein the semiconductive layer has a horizontal upper surface,
the at least one first light-guiding part is between the
sample-holding portion and the optical sensing area, and the at
least one electrical contact and the at least one first
light-guiding part extend substantially in a same horizontal plane,
which is in parallel to and above the horizontal upper surface.
[0020] In some embodiments, the at least one electrical contact is
integrally formed with the at least one first light-guiding
part.
[0021] An optical sensor, according to another aspect of the
present disclosure, comprises a semiconductive layer comprising an
optical sensing area, a sample-holding portion over the optical
sensing area, and a light-guiding structure configured to direct an
emitting light from the sample-holding portion to the optical
sensing area, wherein the light-guiding structure comprises at
least one light-guiding spacer extending from a horizontal upper
surface of the semiconductive layer, and the light-guiding
structure has a tapering top end near the sample-holding
portion.
[0022] In some embodiments, the light-guiding structure comprises a
plurality of light-guiding spacers arranged in a ring.
[0023] In some embodiments, the light-guiding structure comprises a
ring-shaped guiding spacer.
[0024] In some embodiments, the optical sensor comprises a
plurality of dielectric layers over the optical sensing area,
wherein the at least one light-guiding spacer extends through the
plurality of dielectric layers.
[0025] In some embodiments, the light-guiding structure has a
sidewall tilted with respect to the semiconductive layer, and an
included angle between the horizontal upper surface of the
semiconductive layer and the sidewall is about 60 degrees to 89.5
degrees.
[0026] The light-guiding structure is designed to prevent light
scattering. Due to the design of the light-guiding structure, the
emitting light from the sample-holding portion can be more
efficiently directed to the light-sensing region in the optical
sensing area. Furthermore, the fabrication of the light-guiding
structure complies with the back-end-of-line (BEOL) metallization
technology and can be fabricated by the same fabrication process in
the same die as the electrical interconnected structure and the
multi junction photodiode of the light-sensing region. In addition,
the light-guiding structure, the electrical interconnect structure
and the multi junction photodiode of the light-sensing region are
integrated in the same die by the same fabrication process rather
than in two separated devices. Thus, the size of the optical sensor
can be dramatically decreased.
[0027] The foregoing has outlined rather broadly the features and
technical advantages of the present disclosure in order that the
detailed description of the disclosure that follows may be better
understood. Additional features and advantages of the disclosure
will be described hereinafter, which form the subject of the claims
of the disclosure. It should be appreciated by those skilled in the
art that the conception and specific embodiment disclosed may be
readily utilized as a basis for modifying or designing other
structures or processes for carrying out the same purposes of the
present disclosure. It should also be realized by those skilled in
the art that such equivalent constructions do not depart from the
spirit and scope of the disclosure as set forth in the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] A more complete understanding of the present disclosure may
be derived by referring to the detailed description and claims when
considered in connection with the Figures, where like reference
numbers refer to similar elements throughout the Figures, and:
[0029] FIG. 1A is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0030] FIG. 1B is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0031] FIG. 1C is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure
[0032] FIG. 2 is a top view of a light-guiding structure in
accordance with some embodiments of the present disclosure.
[0033] FIG. 3 is a top view of a light-guiding structure in
accordance with some embodiments of the present disclosure.
[0034] FIG. 4 is a top view of a light-guiding structure in
accordance with some embodiments of the present disclosure.
[0035] FIG. 5 to FIG. 10 are cross-sectional views for preparing an
optical sensor in accordance with some embodiments of the present
disclosure.
[0036] FIG. 11A is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0037] FIG. 11B is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0038] FIG. 11C is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure
[0039] FIG. 12 to FIG. 17 are cross-sectional views for preparing
an optical sensor in accordance with some embodiments of the
present disclosure.
[0040] FIG. 18A is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0041] FIG. 18B is a cross-sectional view of an optical sensor in
accordance with some embodiments of the present disclosure.
[0042] FIG. 19 to FIG. 23 are cross-sectional views for preparing
an optical sensor in accordance with some embodiments of the
present disclosure.
DETAILED DESCRIPTION
[0043] The following description of the disclosure accompanies
drawings, which are incorporated in and constitute a part of this
specification, and illustrate embodiments of the disclosure, but
the disclosure is not limited to the embodiments. In addition, the
following embodiments can be properly integrated to complete
another embodiment.
[0044] References to "one embodiment," "an embodiment," "exemplary
embodiment," "other embodiments," "another embodiment," etc.
indicate that the embodiment(s) of the disclosure so described may
include a particular feature, structure, or characteristic, but not
every embodiment necessarily includes the particular feature,
structure, or characteristic. Further, repeated use of the phrase
"in the embodiment" does not necessarily refer to the same
embodiment, although it may.
[0045] The present disclosure is directed to an optical sensor with
a light-guiding feature. In order to make the present disclosure
completely comprehensible, detailed steps and structures are
provided in the following description. Obviously, implementation of
the present disclosure does not limit special details known by
persons skilled in the art. In addition, known structures and steps
are not described in detail, so as not to limit the present
disclosure unnecessarily. Preferred embodiments of the present
disclosure will be described below in detail. However, in addition
to the detailed description, the present disclosure may also be
widely implemented in other embodiments. The scope of the present
disclosure is not limited to the detailed description, and is
defined by the claims.
[0046] FIG. 1A is a cross-sectional view of an optical sensor 100
in accordance with some embodiments of the present disclosure. In
some embodiments, the optical sensor 100 comprises a semiconductive
layer 111 having an electrical circuit area 111A and an optical
sensing area 111B, a sample-holding portion 23 over the optical
sensing area 111B, a light-guiding structure 130 between the
sample-holding portion 23 and the optical sensing area 111B, and an
electrical interconnect structure 140 over the electrical circuit
area 111A. In some embodiments, the light-guiding structure 130 is
configured to direct an emitting light from the sample-holding
portion 23 to the optical sensing area 111B.
[0047] In some embodiments, the semiconductive layer 111 is a
silicon substrate including a light-sensing region 55 in the
optical sensing area 111B used for detecting light of various
wavelengths, and the sample holding portion 23 is used for holding
a specimen 231 under analysis. In some embodiments, the sample
holding portion 23 is disposed in a waveguide structure 120 over
the light-guiding structure 130, and the light-sensing region 55 is
a multi junction photodiode disposed in an epitaxy region below the
light-guiding structure 130. In some embodiments, the light-sensing
region 55 in the semiconductive layer 111 and the sample holding
portion 23 in a waveguide structure 120 are disclosed in U.S.
patent application Ser. No. 14/695,675, and the entire content of
which is incorporated herein for all purposes by this
reference.
[0048] When a light 8 having wavelengths from around 450 nanometers
to around 500 nanometers shines on the specimen 231 in the sample
holding portion 23, the specimen 231 emits lights 81 such as
fluorescent lights, and the light-guiding structure 130 is
configured to direct the emitting lights 81 to the light-sensing
region 55. The wavelength of the emitted fluorescent light, for
example, can be a characteristic of a material in the specimen 231.
For example, in some embodiments, the specimen 231 emits
fluorescent lights with different wavelengths. In some embodiments,
the light-sensing region 55 is electrically connected to the
electrical interconnect structure 140 through conductor so as to
transfer the charge carriers generated in the light sensing region
55 to the electrical circuitry in the electrical interconnect
structure 140 for further signal processing and/or output to
signal-processing electronics, such as a DSP or microprocessor.
[0049] In some embodiments, the electrical interconnect structure
140 is integrally formed with the light-guiding structure 130. In
some embodiments, the correspondingly elements of the electrical
interconnect structure 140 and the light-guiding structure 130 are
formed substantially by the same fabrication process, and have
substantially the same physical and chemical properties.
[0050] In some embodiments, the electrical interconnect structure
140 comprises at least one electrical contact 141 over the
electrical circuit area 111A, and the light-guiding structure 130
comprises at least one first light-guiding part 131 over the
optical sensing area 111B. In some embodiments, the first
light-guiding part 131 is simultaneously formed with the electrical
contact 141 substantially by the same fabrication process and the
same material, and the first light-guiding part 131 and the
electrical interconnect contact 141 have substantially the same
physical and chemical properties.
[0051] In some embodiments, the semiconductive layer 111 has a
horizontal upper surface 112, and the electrical contact 141 and
the first light-guiding part 131 extend substantially in a same
horizontal plane, which is in parallel to and above the horizontal
upper surface 112. In some embodiments, the optical sensor 100 has
a dielectric layer 101 over the horizontal upper surface 112, and
the electrical contact 141 and the first light-guiding part 131 are
positioned in the dielectric layer 101. In some embodiments, the
bottom ends of the electrical contact 141 and the first
light-guiding part 131 are substantially at the same level, the
upper ends of the electrical contact 141 and the first
light-guiding part 131 are substantially at the same level; thus,
the electrical contact 141 and the first light-guiding part 131 can
be formed through the same fabrication process.
[0052] In some embodiments, the electrical interconnect structure
140 comprises at least one electrical via 142 over the electrical
contact 141, and the light-guiding structure 130 comprises at least
one second light-guiding part 132 over the first light-guiding part
131. In some embodiments, the second light-guiding part 132 is
simultaneously formed with the electrical via 142 substantially by
the same fabrication process and the same material, and the second
light-guiding part 132 and the electrical via 142 have
substantially the same physical and chemical properties.
[0053] In some embodiments, the electrical interconnect structure
140 has an electrical metal layer 143 between the electrical via
142 and the electrical contact 141; similarly, the light-guiding
structure 130 has a third light-guiding part 133 between the second
light-guiding part 132 and the first light-guiding part 131. In
some embodiments, the third light-guiding part 133 is
simultaneously formed with the electrical metal layer 143
substantially by the same fabrication process and the same
material, and the third light-guiding part 133 and the electrical
metal layer 143 have substantially the same physical and chemical
properties.
[0054] In some embodiments, the electrical via 142 and the second
light-guiding part 132 extend substantially in a same horizontal
plane, which is in parallel to and above the horizontal upper
surface 112. In some embodiments, the optical sensor 100 has a
dielectric layer 102 over the horizontal upper surface 112, and the
electrical via 142 and the second light-guiding part 132 are
positioned in the dielectric layer 102. In some embodiments, the
bottom ends of the electrical metal layer 143 and the third
light-guiding part 133 are substantially at the same level, the
upper ends of the electrical via 142 and the second light-guiding
part 132 are substantially at the same level; thus, the electrical
contact 141 and the first light-guiding part 131 can be formed
through the same fabrication processes.
[0055] In some embodiments, the optical sensor 100 has a plurality
of dielectric layers 102-104 over the dielectric layer 101, and
each dielectric layer has at least one electrical via 142 and at
least one second light-guiding part 132 extending substantially in
a same horizontal plane. In some embodiments, the second
light-guiding part 132 can be optionally implemented in some of the
dielectric layers, rather than in all of the dielectric layers. In
some embodiments, the light-guiding structure 130 extends
vertically or in a tilt manner from the horizontal upper surface
112 of the semiconductive layer 111. In some embodiments, the
horizontal distance between the second light-guiding parts 132 in
the upper dielectric layer 104 is larger than that in the lower
dielectric layer 102; in other words, the horizontal distance
shrinks along a light-propagating direction from the sample-holding
portion 23 to the light-sensing region 55.
[0056] FIG. 1B is a cross-sectional view of an optical sensor 100'
in accordance with some embodiments of the present disclosure. The
optical sensor 100' shown in FIG. 1B is substantially the same as
the optical sensor 100 shown in FIG. 1A, except the design of the
light-guiding structure. In FIG. 1A, the width of the light-guiding
structure 130 is larger in the upper region (close to the
sample-holding portion 23) than that in the bottom region (close to
the light-sensing region 55); in contrast, in FIG. 1B, the width of
the light-guiding structure 130' is larger in the bottom region
(close to the light-sensing region 55) than that in the upper
region (close to the sample-holding portion 23).
[0057] FIG. 1C is a cross-sectional view of an optical sensor 100''
in accordance with some embodiments of the present disclosure. The
optical sensor 100'' shown in FIG. 1C is substantially the same as
the optical sensor 100 shown in FIG. 1A, except the design of the
light-guiding structure. In FIG. 1A, the width of the light-guiding
structure 130 is larger in the upper region (close to the
sample-holding portion 23) than that in the bottom region (close to
the light-sensing region 55); in contrast, in FIG. 1C, the width of
the light-guiding structure 130'' in the bottom region (close to
the light-sensing region 55) is substantially the same as that in
the upper region (close to the sample-holding portion 23). In other
words, the inner sidewall of the light-guiding structure 130'' is
substantially vertical to the horizontal upper surface 112.
[0058] FIG. 2 is a top view of a light-guiding structure 130A in
accordance with some embodiments of the present disclosure. In some
embodiments, the light-guiding structure 130A comprises a
ring-shaped first light-guiding part 131A and a ring-shaped second
light-guiding part 132A. In some embodiments, the ring-shaped first
light-guiding part 131A can be optionally disposed inside or
outside of the ring-shaped second light-guiding part 132A, and more
second light-guiding parts can be optionally disposed in the
light-guiding structure 130A. In some embodiments, the outer
periphery of the ring-shaped first light-guiding part 131A can be
optionally overlapped with the inner periphery of the ring-shaped
second light-guiding part 132A where the ring-shaped first
light-guiding part 131A is disposed inside the ring-shaped second
light-guiding part 132A, or vice versa.
[0059] FIG. 3 is a top view of a light-guiding structure 130B in
accordance with some embodiments of the present disclosure. In some
embodiments, the light-guiding structure 130B comprises a plurality
of first light-guiding parts 131B arranged in a ring, and a
plurality of second light-guiding parts 132B arranged in a ring. In
some embodiments, the plurality of first light-guiding part 131B
can be optionally disposed inside or outside of the plurality of
second light-guiding parts 132B, and more second light-guiding
parts can be optionally disposed in the light-guiding structure
130B. In some embodiments, the outer periphery of the first
light-guiding part 131B can be optionally overlapped with the inner
periphery of the second light-guiding part 132B where the first
light-guiding part 131B is disposed inside the second light-guiding
part 132B, or vice versa.
[0060] FIG. 4 is a top view of a light-guiding structure 130C in
accordance with some embodiments of the present disclosure. In some
embodiments, the light-guiding structure 130C comprises an inner
light-guiding bar 131C serving as the first light-guiding part in
the dielectric layer 101 over the semiconductive layer 111 and an
outer light-guiding bar 132C serving as the second light-guiding
part in the dielectric layer 102 over the semiconductive layer 111.
In some embodiments, the light-guiding bar 131C can be optionally
disposed inside or outside of the light-guiding bar 132C, and more
light-guiding bars can be optionally disposed in the light-guiding
structure 130C. In some embodiments, the outer periphery of the
inner light-guiding bar can be optionally overlapped with the inner
periphery of the outer light-guiding bar. In some embodiments, each
of the light-guiding bars 131C can be further laterally divided
into serval parts; similarly, each of the light-guiding bars 132C
can be further laterally divided into serval parts. In some
embodiments, the light-guiding bars 131C can be optionally
connected to form an integral rectangular light-guiding ring, and
the light-guiding bars 132C can be optionally connected to form an
integral rectangular light-guiding ring.
[0061] Due to the design purpose of the light-guiding structure 130
to prevent light scattering, the emitting light 81 from the
sample-holding portion 23 can be more efficiently directed to the
light-sensing region 55 in the optical sensing area 111B.
Furthermore, the fabrication of the light-guiding structure 130,
the electrical interconnect structure 140, and the multi junction
photodiode of the light-sensing region 55 comply with the
back-end-of-line (BEOL) metallization technology, and can be
fabricated by the same fabrication process in the same die. In
addition, the light-guiding structure 130, the electrical
interconnect structure 140, and the multi junction photodiode of
the light-sensing region are integrated in the same die by the same
fabrication process rather than in two separated devices. Thus, the
size of the optical sensor 100 can be dramatically decreased.
[0062] FIG. 5 to FIG. 10 are cross-sectional views for preparing an
optical sensor in accordance with some embodiments of the present
disclosure. In some embodiments, the fabrication processes
disclosed in FIG. 5 to FIG. 10 comply with the aluminum
back-end-of-line (BEOL) metallization technology.
[0063] Referring to FIG. 5, in some embodiments, a light-sensing
region 55 is formed in a semiconductive layer 111, electronic
devices 149 such as transistors are formed over an electrical
circuit area 111A, and an inter-layer dielectric layer 101 is then
formed on the semiconductive layer 111 by deposition and
planarization processes. Subsequently, lithographic, etching,
deposition and planarization processes are performed to form
electrical contacts 141 over the electrical circuit area 111A and
form first light-guiding parts 131 over the optical sensing area
111B. In some embodiments, the electrical contact 141 and the first
light-guiding part 131 include tungsten (W).
[0064] Referring to FIG. 6, deposition, lithographic and etching
processes are performed to form an electrical metal layer 143 over
the electrical contact 141 and form a third light-guiding part 133
over the first light-guiding part 131. In some embodiments, the
electrical metal layer 143 and the third light-guiding part 133
include aluminum (Al).
[0065] Referring to FIG. 7, an inter-metal dielectric layer 102 is
formed on the inter-layer dielectric layer 101 by deposition and
planarization processes. In some embodiments, the inter-metal
dielectric layer 102 includes a lower portion 102A formed by an HDP
deposition process and an upper layer 102B formed by a PECVD
process.
[0066] Referring to FIG. 8, lithographic, etching, deposition and
planarization processes are performed to form electrical vias 142
over the electrical contacts 141 and form second light-guiding
parts 132 over the first light-guiding parts 131. In some
embodiments, the electrical via 142 and the second light-guiding
part 132 include tungsten (W).
[0067] Referring to FIG. 9, the fabrication processes disclosed in
FIG. 6, FIG. 7 and FIG. 8 are repeated to form a plurality of
inter-metal dielectric layers 103-105 having the second
light-guiding parts 132, the electrical vias 142, the third
light-guiding part 133, and the electrical metal layer 143.
Subsequently, a metal layer 147 having an opening 147A is formed by
fabrication processes including deposition, lithographic and
etching processes, wherein the opening 147A can be a rectangular
opening. The metal layer 147 serves as a light shielding layer,
wherein the opening 147A exposes the light sensing region 55 for
receiving the light from the sample-holding portion 23, while the
metal layer 147 covers the other regions. In addition, the metal
layer 147 can serve as a contact pad for forming electrical
connection to an external printed circuit board (PCB) by wire
bonding. In some embodiment, the thickness of the metal layer 147
is larger than that of the metal layer below, and the thickness of
the metal layer 147 is preferably larger than 4,000 angstroms.
[0068] Subsequently, dielectric deposition and planarization
processes are performed to form a dielectric layer 106 on the metal
layer 147 and fills the opening 147A. In some embodiments, the
dielectric deposition is a PECVD process, and the planarization is
an oxide CMP process. In some embodiments, the dielectric
deposition includes a spin-on glass (SOG), SOG curing, SOG etching
back, and a PECVD process. In some embodiments, the dielectric
layer 106 includes silicon oxide or silicon nitride, and silicon
nitride is preferred for absorbing background light having a
wavelength of 488 nanometers.
[0069] Referring to FIG. 10, a deposition process is performed to
form a filter layer 119 over the inter-metal dielectric layer 105.
Next, deposition processes are performed to form a lower cladding
layer 121 and a core layer 123 over the filter layer 119;
subsequently, deposition, lithographic and etching processes are
performed to an upper cladding layer 125 having a sample-holding
portion 23 over the light sensing region 55. In some embodiments,
the refractive index of the core layer 123 is higher than that of
the cladding layers 121 and 125.
[0070] In some embodiment, the filter layer 119 is transparent to
the wavelength emitted from the specimen 231, and the emitting
light 81 from the sample-holding portion 23 travels through the
filter layer 119 toward the light-sensing region 55. The lower
cladding layer 121, the core layer 123, and the upper cladding
layer 125 form a waveguide structure 120. In some embodiments, the
lower cladding layer 121 and the upper cladding layer 125 include
oxide such as SiO.sub.2. In some embodiments, the core layer 123
includes dielectric such as Ta.sub.2O.sub.5 or SiON.
[0071] In summary, the embodiment shown in FIG. 5 to FIG. 10 is
characterized in integrally forming the light-guiding structure
(first light-guiding part, second light-guiding part, third
light-guiding part) and the electrical interconnect structure
(electrical contact, electrical via, electrical metal layer), i.e.,
substantially by the same fabrication process and the same material
simultaneously, and the corresponding elements of the light-guiding
structure and the electrical interconnect structure have
substantially the same physical and chemical properties. In
addition, integrally forming the light-guiding structure and the
electrical interconnect structure not only decreases the
fabrication cost, but also simplify the fabrication process.
[0072] FIG. 11A is a cross-sectional view of an optical sensor 200
in accordance with some embodiments of the present disclosure. In
some embodiments, the optical sensor 200 comprises a semiconductive
layer 111 comprising an electrical circuit area 111A and an optical
sensing area 111B, a sample-holding portion 23 over the optical
sensing area 111B, an electrical interconnect structure 240
including at least one electrical contact 141 over the electrical
circuit area 111A, and a light-guiding structure 230 including at
least one first light-guiding part 131 between the sample-holding
portion 23 and the optical sensing area 111A.
[0073] In some embodiments, the electrical interconnect structure
240 is integrally formed with the light-guiding structure 230. In
some embodiments, the elements of the electrical interconnect
structure 240 and the elements of the light-guiding structure 230
are formed substantially by the same fabrication process, and have
substantially the same physical and chemical properties.
[0074] In some embodiments, the first light-guiding part 131 is
simultaneously formed with the electrical contact 141 substantially
by the same fabrication process and the same material, and the
first light-guiding part 131 and the electrical interconnect
contact 141 have substantially the same physical and chemical
properties. In some embodiments, the semiconductive layer 111 has a
horizontal upper surface 112, the at least one electrical contact
141 and the at least one first light-guiding part 131 extend
substantially in a same horizontal plane, which is in parallel to
and above the horizontal upper surface 112, and the light-guiding
structure 230 is configured to direct an emitting light 81 from the
sample-holding portion 23 to the optical sensing area 111A.
[0075] In some embodiments, the optical sensor 200 comprises an
inter-layer dielectric layer 101 and a plurality of inter-metal
dielectric layers 202-205, wherein the inter-layer dielectric layer
101 has the electrical contact 141 and the first light-guiding part
131, while the inter-metal dielectric layers 202-205 have at least
one electrical via 242 and at least one electrical metal layer 243
over the electrical circuit area 111A, and at least one second
light-guiding part 232 and at least one third light-guiding part
233 over the optical sensing area 111B. In some embodiments, the
light-guiding structure 230 can use the ring-shaped layout shown in
FIG. 3, the part layout in a ring shown in FIG. 4, or the bar
layout shown in FIG. 5.
[0076] In some embodiments, the third light-guiding part 233 is
simultaneously formed with the electrical metal layer 243
substantially by the same fabrication process and the same
material, and the third light-guiding part 233 and the electrical
metal layer 243 have substantially the same physical and chemical
properties. In some embodiments, the electrical metal layer 243 and
the third light-guiding part 233 extend substantially in a same
horizontal plane, which is in parallel to and above the horizontal
upper surface 112. The upper ends of the electrical metal layer 243
and the third light-guiding part 233 are substantially at the same
level, and the bottom ends of the electrical metal layer 243 and
the third light-guiding part 233 are substantially at the same
level, and they can be formed through the same fabrication
processes.
[0077] In some embodiments, the second light-guiding part 232 is
simultaneously formed with the electrical via 242 substantially by
the same fabrication process and the same material, and the second
light-guiding part 232 and the electrical via 242 have
substantially the same physical and chemical properties. In some
embodiments, the electrical via 242 and the second light-guiding
part 232 extend substantially in a same horizontal plane, which is
in parallel to and above the horizontal upper surface 112. The
upper ends of the electrical via 242 and the second light-guiding
part 232 are substantially at the same level, and the bottom ends
of the electrical via 242 and the second light-guiding part 232 are
substantially at the same level, and they can be formed through the
same fabrication processes.
[0078] In some embodiments, the second light-guiding part 232 can
be optionally implemented in some of the dielectric layers, rather
than in all of the dielectric layers. In some embodiments, the
horizontal distance between the second light-guiding parts 232 in
the upper dielectric layer 205 is larger than that in the lower
dielectric layer 203; in other words, the horizontal distance
shrinks along a light-propagating direction from the sample-holding
portion 23 to the light-sensing region 55 in the optical sensing
area 111B. In some embodiments, the light-guiding structure 230
extends vertically or in a tilt manner from the horizontal upper
surface 112 of the semiconductive layer 111.
[0079] In some embodiments, the light-sensing region 55 is
electrically connected to the electrical interconnect structure 240
through conductor so as to transfer the charge carriers generated
in the light sensing region 55 to the electrical circuitry in the
electrical interconnect structure 240 for further signal processing
and/or output to signal-processing electronics, such as a DSP or
microprocessor.
[0080] FIG. 11B is a cross-sectional view of an optical sensor 200'
in accordance with some embodiments of the present disclosure. The
optical sensor 200' shown in FIG. 11B is substantially the same as
the optical sensor 200 shown in FIG. 11A, except the design of the
light-guiding structure. In FIG. 11A, the width of the
light-guiding structure 230 is larger in the upper region (close to
the sample-holding portion 23) than that in the bottom region
(close to the light-sensing region 55); in contrast, in FIG. 11B,
the width of the light-guiding structure 230' is larger in the
bottom region (close to the light-sensing region 55) than that in
the upper region (close to the sample-holding portion 23).
[0081] FIG. 11C is a cross-sectional view of an optical sensor
200'' in accordance with some embodiments of the present
disclosure. The optical sensor 200'' shown in FIG. 11C is
substantially the same as the optical sensor 200 shown in FIG. 11A,
except the design of the light-guiding structure. In FIG. 11A, the
width of the light-guiding structure 230 is larger in the upper
region (close to the sample-holding portion 23) than that in the
bottom region (close to the light-sensing region 55); in contrast,
in FIG. 11C, the width of the light-guiding structure 230'' in the
bottom region (close to the light-sensing region 55) is
substantially the same as that in the upper region (close to the
sample-holding portion 23). In other words, the inner sidewall of
the light-guiding structure 230'' is substantially vertical to the
horizontal upper surface 112.
[0082] Due to the design purpose of the light-guiding structure 230
to prevent light scattering, the emitting light 81 from the
sample-holding portion 23 can be more efficiently directed to the
light-sensing region 55 in the optical sensing area 111B.
Furthermore, the fabrication of the light-guiding structure 230,
the electrical interconnect structure 240 and the multi junction
photodiode of the light-sensing region 55 comply with the
back-end-of-line (BEOL) metallization technology, and can be
fabricated by the same fabrication process in the same die. In
addition, the light-guiding structure 230, the electrical
interconnect structure 240, and the multi junction photodiode of
the light-sensing region 55 are integrated in the same die by the
same fabrication process rather than in two separated devices.
Thus, the size of the optical sensor 200 can be dramatically
decreased.
[0083] FIG. 12 to FIG. 17 are cross-sectional views for preparing
an optical sensor in accordance with some embodiments of the
present disclosure. In some embodiments, the fabrication processes
disclosed in FIG. 12 to FIG. 17 comply with the copper
back-end-of-line (BEOL) metallization technology.
[0084] Referring to FIG. 12, in some embodiments, a light-sensing
region 55 is formed in a semiconductive layer 111, electronic
devices 149 such as transistors are formed over an electrical
circuit area 111A, and an inter-layer dielectric layer 101 is then
formed on the semiconductive layer 111 by deposition and
planarization processes. Subsequently, lithographic, etching,
deposition and planarization processes are performed to form
electrical contacts 141 over the electrical circuit area 111A and
form first light-guiding parts 131 over the optical sensing area
111B.
[0085] Referring to FIG. 13, deposition, lithographic and etching
processes are performed to form an inter-metal dielectric layer 202
having an aperture 2021A and an aperture 2021B, which expose the
first light-guiding part 131 over the electrical circuit area 111A
and the electrical contact 141 over the optical sensing area
111B.
[0086] Referring to FIG. 14, deposition and planarization processes
are performed to form at least one electrical metal layer 243 in
the aperture 2021A over the electrical contact 141 and form at
least one third light-guiding part 233 in the aperture 2021B over
the first light-guiding part 131. In some embodiments, the
electrical metal layer 243 and the third light-guiding part 233
include copper (Cu).
[0087] Referring to FIG. 15, deposition, lithographic and etching
processes are performed to form an inter-metal dielectric layer 203
over the inter-metal dielectric layer 202. Subsequently, deposition
and planarization processes are performed to form an electrical via
242 over the electrical contact 141 and form a second light-guiding
part 232 over the first light-guiding part 131. In some
embodiments, the electrical metal layer 243 and the third
light-guiding part 233 include copper (Cu).
[0088] Referring to FIG. 16, the fabrication processes disclosed in
FIG. 15 are repeated to form a plurality of inter-metal dielectric
layers 204-205, a plurality of second light-guiding parts 232 over
the optical sensing area 111B, and a plurality of electrical vias
242 over the electrical circuit area 111A. Subsequently, a metal
layer 147 having an opening 147A is formed by fabrication processes
including deposition, lithographic and etching processes, wherein
the opening 147A can be a rectangular opening. The metal layer 147
serves as a light shielding layer, wherein the opening 147A exposes
the light sensing region 55 for receiving the light from the
sample-holding portion 23, while the metal layer 147 covers the
other regions. In addition, the metal layer 147 can serve as a
contact pad for forming electrical connection to an external
printed circuit board (PCB) by wire bonding. In some embodiment,
the thickness of the metal layer 147 is larger than that of the
metal layer below, and the thickness of the metal layer 147 is
preferably larger than 4,000 angstroms.
[0089] Subsequently, dielectric deposition and planarization
processes are performed to form a dielectric layer 106 on the metal
layer 147 and fills the opening 147A. In some embodiments, the
dielectric deposition is a PECVD process, and the planarization is
an oxide CMP process. In some embodiments, the dielectric
deposition includes a spin-on glass (SOG), SOG curing, SOG etching
back, and a PECVD process. In some embodiments, the dielectric
layer 106 includes silicon oxide or silicon nitride, and silicon
nitride is preferred for absorbing background light having a
wavelength of 488 nanometers.
[0090] Referring to FIG. 17, a deposition process is performed to
form a filter layer 119 over the inter-metal dielectric layer 205.
Next, deposition processes are performed to form a lower cladding
layer 121 and a core layer 123 over the filter layer 119;
subsequently, deposition, lithographic and etching processes are
performed to an upper cladding layer 125 having a sample-holding
portion 23 over the light sensing region 55.
[0091] In some embodiment, the filter layer 119 is transparent to
the wavelength emitted from the specimen 231, and the emitting
light 81 from the sample-holding portion 23 travels through the
filter layer 119 toward the light-sensing region 55. The lower
cladding layer 121, the core layer 123, and the upper cladding
layer 125 form a waveguide structure 120. In some embodiments, the
lower cladding layer 121 and the upper cladding layer 125 include
oxide such as SiO.sub.2. In some embodiments, the core layer 123
includes dielectric such as Ta.sub.2O.sub.5 or SiON.
[0092] In summary, the embodiment shown in FIG. 12 to FIG. 17 is
characterized in integrally forming the light-guiding structure
(first light-guiding part, second light-guiding part, third
light-guiding part) and the electrical interconnect structure
(electrical contact, electrical via, electrical metal layer), i.e.,
substantially by the same fabrication process and the same material
simultaneously, and the corresponding elements of the light-guiding
structure and the electrical interconnect structure have
substantially the same physical and chemical properties. In
addition, integrally forming the light-guiding structure and the
electrical interconnect structure not only decreases the
fabrication cost, but also simplify the fabrication process.
[0093] FIG. 18A is a cross-sectional view of an optical sensor 300
in accordance with some embodiments of the present disclosure. In
some embodiments, the optical sensor 300 comprises a semiconductive
layer 111 having an optical sensing area 111B, a sample-holding
portion 23 over the optical sensing area 111B, and a light-guiding
structure 330 configured to direct an emitting light 81 from the
sample-holding portion 23 to the optical sensing area 111B. The
light-guiding structure 330 comprises at least one light-guiding
spacer 331 and extends from a horizontal upper surface 112 of the
semiconductive layer 111, and the light-guiding structure 330 has a
tapering top end 332 near the sample-holding portion 23.
[0094] In some embodiments, the optical sensor 100 has a plurality
of dielectric layers 101-105 over the optical sensing area 111B,
and the light-guiding spacer 331 is a wall extending from the
horizontal upper surface 112 of the semiconductive layer 111
through the plurality of dielectric layers 101-105. In some
embodiments, the light-guiding spacer 331 can optionally extend
vertically or in a tilt manner from the horizontal upper surface
112 through the plurality of dielectric layers 101-105. In some
embodiments, the light-guiding structure 330 can use the
ring-shaped layout shown in FIG. 3, the part layout in a ring shown
in FIG. 4, or the bar layout shown in FIG. 5.
[0095] FIG. 18B is a cross-sectional view of an optical sensor 300'
in accordance with some embodiments of the present disclosure. The
optical sensor 300' shown in FIG. 18B is substantially the same as
the optical sensor 300 shown in FIG. 18A, except the design of the
light-guiding structure. In FIG. 18B, the sidewall 331 of the
light-guiding structure 330' is tilted with respect to the
semiconductive layer 111, wherein the included angle (.theta.)
between the horizontal upper surface 112 of the semiconductive
layer 111 and the sidewall 331 of the light-guiding structure 330'
is about 60 degrees to 89.5 degrees.
[0096] Due to the design purpose of the light-guiding structure 330
having a smooth inner sidewall to prevent light scattering, the
emitting light 81 from the sample-holding portion 23 can be more
efficiently directed to the light-sensing region 55 in the optical
sensing area 111B. Furthermore, the fabrication of the
light-guiding structure 330 complies with the back-end-of-line
(BEOL) metallization technology, and can be fabricated by the same
fabrication process in the same die as the electrical
interconnected structure 140 and the multi junction photodiode of
the light-sensing region 55. In addition, the light-guiding
structure 130, the electrical interconnect structure 140 and the
multi junction photodiode of the light-sensing region 55 are
integrated in the same die by the same fabrication process rather
than in two separated devices. Thus, the size of the optical sensor
300 can be dramatically decreased.
[0097] FIG. 19 to FIG. 23 are cross-sectional views for preparing
an optical sensor in accordance with some embodiments of the
present disclosure. In some embodiments, the fabrication processes
disclosed in FIG. 19 to FIG. 23 comply with both the aluminum
back-end-of-line (BEOL) metallization technology and the copper
back-end-of-line (BEOL) metallization technology.
[0098] Referring to FIG. 19, in some embodiments, a light-sensing
region 55 is formed in a semiconductive layer 111, and electronic
devices 149 such as transistors are formed over an electrical
circuit area 111A. Subsequently, lithographic, etching, deposition
and planarization processes are performed to form an electrical
interconnect structure 140 having electrical contacts 141,
electrical metal layers 143, and electrical vias 142 over an
electrical circuit area 111A of the semiconductive layer 111.
[0099] Referring to FIG. 20, lithographic and etching processes are
performed to form an aperture 301 over the light-sensing region 55
in the optical sensing area 111B. Subsequently, a metal disposition
process is performed to form a metal layer 302 on the sidewall of
the aperture 301 and the upper surface of the dielectric layer
105.
[0100] Referring to FIG. 21, a metal etching back process is
performed to remove a portion of the metal layer 302 to form a
metal spacer on the sidewall of the aperture 301. Subsequently,
dielectric deposition and planarization processes are performed to
form a dielectric layer 303 filling the aperture 301. In some
embodiments, the dielectric layer 303 includes dielectric such as
silicon oxide or silicon nitride, and silicon nitride is preferred
for absorbing background light having a wavelength of 488
nanometers. Next, a metal layer 147 having an opening 147A is
formed by fabrication processes including deposition, lithographic
and etching processes, wherein the opening 147A can be a
rectangular opening. The metal layer 147 serves as a light
shielding layer, wherein the opening 147A exposes the light sensing
region 55 for receiving the light from the sample-holding portion
23, while the metal layer 147 covers the other regions. In
addition, the metal layer 147 can serve as a contact pad for
forming electrical connection to an external printed circuit board
(PCB) by wire bonding. In some embodiment, the thickness of the
metal layer 147 is larger than that of the metal layer below, and
the thickness of the metal layer 147 is preferably larger than
4,000 angstroms.
[0101] Referring FIG. 22, dielectric deposition and planarization
processes are performed to form a dielectric layer 304 on the metal
layer 147 and fills the aperture 301 and the opening 147A. In some
embodiments, the dielectric deposition is a PECVD process, and the
planarization is an oxide CMP process. In some embodiments, the
dielectric deposition includes a spin-on glass (SOG), SOG curing,
SOG etching back, and a PECVD process. In some embodiments, the
dielectric layer 304 includes dielectric such as silicon oxide or
silicon nitride, and silicon nitride is preferred for absorbing
background light having a wavelength of 488 nanometers.
[0102] Referring to FIG. 23, a deposition process is performed to
form a filter layer 119 over the inter-metal dielectric layer 105.
Next, deposition processes are performed to form a lower cladding
layer 121 and a core layer 123 over the filter layer 119;
subsequently, deposition, lithographic and etching processes are
performed to an upper cladding layer 125 having a sample-holding
portion 23 over the light sensing region 55.
[0103] In some embodiment, the filter layer 119 is transparent to
the wavelength emitted from the specimen 231, and the emitting
light 81 from the sample-holding portion 23 travels through the
filter layer 119 toward the light-sensing region 55. The lower
cladding layer 121, the core layer 123, and the upper cladding
layer 125 form a waveguide structure 120. In some embodiments, the
lower cladding layer 121 and the upper cladding layer 125 include
oxide such as SiO.sub.2. In some embodiments, the core layer 123
includes dielectric such as Ta.sub.2O.sub.5 or SiON.
[0104] Some embodiments of the present disclosure provide an
optical sensor. The optical sensor includes a semiconductive layer
comprising an electrical circuit area and an optical sensing area,
a sample-holding portion over the optical sensing area, a
light-guiding structure between the sample-holding portion and the
optical sensing area, and an electrical interconnect structure over
the electrical circuit area. The electrical interconnect structure
is integrally formed with the light-guiding structure, and the
light-guiding structure is configured to direct an emitting light
from the sample-holding portion to the optical sensing area.
[0105] Some embodiments of the present disclosure provide an
optical sensor. The optical sensor includes a semiconductive layer
comprising an electrical circuit area and an optical sensing area,
a sample-holding portion over the optical sensing area, at least
one electrical contact over the electrical circuit area, and at
least one first light-guiding part configured to direct an emitting
light from the sample-holding portion to the optical sensing area.
The semiconductive layer has a horizontal upper surface, the at
least one first light-guiding part is between the sample-holding
portion and the optical sensing area, and the at least one
electrical contact and the at least one first light-guiding part
extend substantially in a same horizontal plane, which is in
parallel to and above the horizontal upper surface.
[0106] Some embodiments of the present disclosure provide an
optical sensor. The optical sensor includes a semiconductive layer
comprising an optical sensing area, a sample-holding portion over
the optical sensing area, and a light-guiding structure configured
to direct an emitting light from the sample-holding portion to the
optical sensing area. The light-guiding structure comprises at
least one light-guiding spacer and extends from a horizontal upper
surface of the semiconductive layer, and the light-guiding
structure has a tapering top end near the sample-holding
portion.
[0107] The light-guiding structure is designed to prevent light
scattering. Due to the design of the light-guiding structure, the
emitting light from the sample-holding portion can be more
efficiently directed to the light-sensing region in the optical
sensing area. Furthermore, the fabrication of the light-guiding
structure complies with the back-end-of-line (BEOL) metallization
technology, and can be fabricated by the same fabrication process
in the same die as the electrical interconnected structure and the
multi junction photodiode of the light-sensing region. In addition,
the light-guiding structure, the electrical interconnect structure
and the multi junction photodiode of the light-sensing region are
integrated in the same die by the same fabrication process rather
than in two separated devices. Thus, the size of the optical sensor
can be dramatically decreased.
[0108] Although the present disclosure and its 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, many of the processes discussed above
can be implemented in different methodologies and replaced by other
processes, or a combination thereof.
[0109] Moreover, the scope of the present application is not
intended to be limited to the particular embodiments of the
process, machine, manufacture, composition of matter, means,
methods and 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.
* * * * *