U.S. patent application number 11/633566 was filed with the patent office on 2007-04-05 for optical device.
This patent application is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Eizou Fujii, Toshiyuki Fukuda, Masanori Minamio.
Application Number | 20070075324 11/633566 |
Document ID | / |
Family ID | 36460174 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070075324 |
Kind Code |
A1 |
Minamio; Masanori ; et
al. |
April 5, 2007 |
Optical device
Abstract
An optical device according to the present invention includes a
device substrate, a translucent member, an optical element chip and
a conductive portion. On a surface of the device substrate, an
opening is provided so as to extend substantially in the vertical
direction with respect to a surface of the device substrate and
pass through the device substrate, the translucent member is
provided so as to cover a first opening mouth of the opening, and
the optical element chip is provided so as to cover the other
opening mouth thereof. Part of the conductive portion is buried in
the device substrate. The outline of the first opening mouth has a
point-asymmetrical shape with respect to an approximate center
point of the first opening mouth.
Inventors: |
Minamio; Masanori; (Osaka,
JP) ; Fujii; Eizou; (Osaka, JP) ; Fukuda;
Toshiyuki; (Kyoto, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
Matsushita Electric Industrial Co.,
Ltd.
Osaka
JP
|
Family ID: |
36460174 |
Appl. No.: |
11/633566 |
Filed: |
December 5, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11244083 |
Oct 6, 2005 |
7166908 |
|
|
11633566 |
Dec 5, 2006 |
|
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Current U.S.
Class: |
257/98 ; 257/99;
257/E31.117; 257/E33.058; 257/E33.073 |
Current CPC
Class: |
H01L 2224/05568
20130101; H01L 33/58 20130101; H01L 2924/00014 20130101; H01L 31/18
20130101; H01L 33/486 20130101; H01L 2224/0554 20130101; H01L
2924/15311 20130101; H01L 2924/1532 20130101; H01L 31/0203
20130101; H01L 2224/16 20130101; H01L 2924/16195 20130101; H01L
2224/05573 20130101; H01L 27/14618 20130101; H01L 27/14683
20130101; H01L 2924/00014 20130101; H01L 2224/05599 20130101; H01L
2924/00014 20130101; H01L 2224/0555 20130101; H01L 2924/00014
20130101; H01L 2224/0556 20130101 |
Class at
Publication: |
257/098 ;
257/099; 257/E33.058 |
International
Class: |
H01L 33/00 20060101
H01L033/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 22, 2004 |
JP |
2004-337309 |
Claims
1-4. (canceled)
5. An optical device comprising: a device substrate including an
opening formed so as to extend substantially in the vertical
direction with respect to a surface of the device substrate and
pass through the device substrate; a translucent member provided so
as to cover a first opening mouth of the opening; an optical
element chip provided so as to cover a second opening mouth of the
opening and including an optical element formation surface in which
an optical element for emitting or receiving light is formed; a
conductive portion provided so as to have part buried in the device
substrate and including first terminal portions each of which is
electrically connected to the optical element and second terminal
portions each of which is electrically connected to a wiring board;
and an encapsulant for encapsulating an electrical connection
portion of the optical element and each of the first terminal
portions, wherein the optical element formation surface faces the
translucent member, and wherein an orientation-indicating marker
for indicating a position orientation of the second terminal
portions in the device substrate is formed in a surface of the
optical element chip located in an opposite side to the optical
element formation surface.
6. The optical device of claim 5, wherein the
orientation-indicating marker is formed of at least a character or
a symbol.
7. An optical device comprising: a device substrate including an
opening formed so as to extend substantially in the vertical
direction with respect to a surface of the device substrate and
pass through the device substrate; a translucent member provided so
as to cover a first opening mouth of the opening; an optical
element chip provided so as to cover a second opening mouth of the
opening and including an optical element for emitting or receiving
light in a surface of the optical element chip facing the
translucent member; a conductive portion provided so as to have
part buried in the device substrate and including first terminal
portions each of which is electrically connected to the optical
element and second terminal portions each of which is electrically
connected to a wiring board; and an encapsulant for encapsulating
an electrical connection portion of the optical element and each of
the first terminal portions, wherein an orientation-indicating
through hole for indicating a position orientation of the second
terminal portions in the device substrate is formed.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn.
119(a) on Japanese Patent Application No. 2004-337309 filed on Nov.
22, 2004, the entire contents of which are hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to optical devices and more
particularly relates to an optical device including an optical
element chip in which an optical device for emitting and receiving
light.
[0004] 2. Description of the Prior Art
[0005] Conventionally, optical semiconductor devices such as CCD
modules included in a video camera, a digital camera, a digital
still camera and the like have been known.
[0006] For example, in Japanese Laid-Open Publication No.
2002-43554, a CCD package module 90 packaged by a flip-chip bonding
technique are disclosed. In the CCD package module 90, as shown in
Japanese Laid-Open Publication No. 2002-43554, a direct circuit
(device substrate) 94 is provided mainly on a bottom surface of a
glass (translucent member) 92, and the direct circuit 94 is bonded
to an image capture chip (optical element chip) 91 by flip-chip
packaging bonding. Furthermore, the direct circuit 94 is bonded to
a printing circuit board (wiring board) 96 via a tin ball 93 by
circuit binding. Then, a circuit is formed and packaged using the
flip-chip bonding technique or various different substrates are
combined to one another by the flip-chip bonding technique to form
a package module for a thin type CCD image capture chip. Thus, the
thickness of a package module for an image capture chip of a charge
coupled device can be reduced. Moreover, light subjected to image
processing by the CCD package module 90 passes through an imaging
loci p and is received by an image capture chip 91.
[0007] As for the CCD package module 90, with the image capture
chip 91 mounted on the printing circuit board 96, a voltage is
applied to the image capture chip 91, thereby performing image
processing. Therefore, it is necessary to mount the image capture
chip 91 on the printing circuit board 96 so that the image capture
chip 91 is properly placed on the printing circuit board 96.
Specifically, the image capture chip 91 has to be mounted onto the
printing circuit board so that the tin ball 93 electrically
connected to an input/output terminal of the image capture chip 91
and a connection terminal provided on the printing circuit board 96
and corresponding to the tin ball 93 are matched in position.
Assume that the image capture chip 91 is placed and mounted onto
the printing circuit board 96 in a wrong manner. For example, if
the image capture chip 91 is placed and mounted with being shifted
by 180 degrees with respect to the printing circuit board 96, there
might be cases where a voltage is not applied to the image capture
chip 91 and, as a result, image processing can not be
performed.
[0008] Furthermore, in recent years, miniaturization of a video
camera, a digital camera, a digital still camera and the like has
been desired. Accordingly, reduction in the size of an optical
device included in such a device is also desired.
SUMMARY OF THE INVENTION
[0009] In view of the points described above, the present invention
has been devised and it is therefore an object of the present
invention to provide an optical device in which orientation
identification is allowed and of which size can be reduced.
[0010] A first optical device according to the present invention
includes: a device substrate including an opening formed so as to
extend substantially in the vertical direction with respect to a
surface of the device substrate and pass through the device
substrate; a translucent member provided so as to cover a first
opening mouth of the opening; an optical element chip provided so
as to cover a second opening mouth of the opening and including an
optical element for emitting or receiving light in a surface of the
optical element chip facing the translucent member; a conductive
portion provided so as to have part buried in the device substrate
and including first terminal portions each of which is electrically
connected to the optical element and second terminal portions each
of which is electrically connected to a wiring board; and an
encapsulant for encapsulating an electrical connection portion of
the optical element and each of the first terminal portions. In the
first optical device, an outline shape of the first opening mouth
is point-asymmetrical with respect to an approximate center point
of the first opening mouth.
[0011] Herein, the opening is a three-dimensional space and each of
the first opening mouth and the second opening mouth is a
two-dimensional area in a surface of the device substrate.
Specifically, the first opening mouth is an opening mouth located
in one surface of the device substrate and covered by the
translucent member, the second opening mouth is an opening mouth
located in the other surface of the device substrate and covered by
the optical element chip, and the opening is a pillar-shaped space
with the first opening mouth as one base and the second opening
mouth as the other base.
[0012] Moreover, the approximate center point substantially
coincides with the barycenter of the outline of the first opening
mouth. It is preferable that the approximate center point of the
first opening mouth coincides with the center point of the device
substrate.
[0013] In the first optical device, it is preferable that the first
opening mouth having a point-asymmetrical outline shape has the
function of indicating a position orientation of the second
terminal portions in the device substrate.
[0014] Herein, the position orientation of the second terminal
portions means to be an orientation identified by positions of
terminals having specific functions, respectively. Functions of the
terminals are an input terminal for inputting a voltage to the
optical element, an output terminal for outputting a outputting a
voltage to the wiring board, a power supply terminal and the like.
For example, the position orientation of the second terminal
portions is different between the case where the input terminal,
the output terminal, the power supply terminal are arranged in this
order from left to right and the case where the power supply
terminal, the output terminal, and the input terminal are arranged
in this order from left to right. Moreover, "the first opening
mouth having a point-asymmetrical outline shape has the function of
indicating a position orientation of the second terminal portions"
means that the position orientation of the second terminal sections
can be uniquely defined by visual identification and measurement of
the outline shape of the first opening mouth.
[0015] In one preferred embodiment of the first optical device, an
outline of the first opening mouth has an approximate rectangular
shape obtained by linearly cutting off at least a portion including
a vertex of a rectangle. In other words, the outline shape of the
first opening mouth in this case is a point-asymmetrical polygon of
which at least two interior angles are obtuse angles and other
interior angles are right angles. In this case, the approximate
center of the first opening mouth is a center point of the
rectangular shape.
[0016] In another preferred embodiment of the first optical device,
an outline of the first opening mouth has an approximate
rectangular shape obtained by roundly cutting off at least a
portion including a vertex of a rectangle. In other words, the
outline shape of the first opening mouth in this case is a shape
having a circumference with part including one of four vertexes of
a rectangle and having an arc-shape. In another way, the outline
shape of the first opening mouth can be described as a shape having
a circumference with part including one of four vertexes of a
rectangle and formed into a rounded corner. Also, in this case, the
approximate center of the first opening mouth is a center point of
the rectangular shape.
[0017] Moreover, in the first optical device, the outline of the
first opening mouth may have a shape obtained by forming an area
reduction portion at least in part of the outline of a regular
polygon so that the area of the first opening mouth is smaller than
the area of the polygon. In said one preferred embodiment, the
portion including at least a vertex of the rectangle and linearly
cut off is the area reduction portion. In said another preferred
embodiment, the portion including at least a vertex of the
rectangle and roundly cut off is the area reduction portion. Also,
the area reduction portion may be a concave portion formed at least
in a side of a rectangle. The shape of the concave portion is not
particularly limited. In such a case, the approximate center point
of the first opening mouth is a center point of the regular
polygon.
[0018] Moreover, in the first optical device, the outline of the
first opening mouth may have a shape obtained by forming an area
increasing portion at least in part of the outline of a regular
polygon so that the area of the first opening mouth is larger than
the area of the polygon. It is preferable that the area increasing
portion is provided as a single piece with the regular polygon in
at least part of the outline of the regular polygon. The shape of
the area increasing portion may be part of a circuit, part of a
polygon and the like and is not particularly limited. In this case,
an approximate center point of the first opening mouth is a center
point of the regular polygon.
[0019] Furthermore, in the first optical device, the outline of the
first opening mouth may have a shape obtained by forming an area
reduction portion at least in part of the outline of a circle so
that the area of the first opening mouth is smaller than the area
of the circle. Moreover, in the first optical device, the outline
of the first opening mouth may have a shape obtained by forming an
area increasing portion at least in part of the outline of a circle
so that the area of the first opening mouth is larger than the area
of the circle. It is preferable that a specific example of each of
the area reduction portion and the area increasing section is
formed in the above-described manner. In this case, the approximate
center point of the first opening mouth is a center point of the
circle.
[0020] A second optical device according to the present invention
includes: a device substrate including an opening formed so as to
extend substantially in the vertical direction with respect to a
surface of the device substrate and pass through the device
substrate; a translucent member provided so as to cover a first
opening mouth of the opening; an optical element chip provided so
as to cover a second opening mouth of the opening and including an
optical element formation surface in which an optical element for
emitting or receiving light is formed; a conductive portion
provided so as to have part buried in the device substrate and
including first terminal portions each of which is electrically
connected to the optical element and second terminal portions each
of which is electrically connected to a wiring board; and an
encapsulant for encapsulating an electrical connection portion of
the optical element and each of the first terminal portions. In the
second optical device, the optical element formation surface faces
the translucent member, and an orientation-indicating marker for
indicating a position orientation of the second terminal portions
in the device substrate is formed in a surface of the optical
element chip located in an opposite side to the optical element
formation surface. It is preferable that the orientation-indicating
marker is given in a known marking method.
[0021] Moreover, in the second optical device, it is preferable
that the orientation-indicating marker is formed of at least a
character or a symbol. "The orientation-indicating marker is formed
of at least a character or a symbol" means that the
orientation-indicating marker is formed of at least a character, or
at least a symbol, or a combination of one or more characters and
one or more symbols.
[0022] A third optical device according to the present invention
includes: a device substrate including an opening formed so as to
extend substantially in the vertical direction with respect to a
surface of the device substrate and pass through the device
substrate; a translucent member provided so as to cover a first
opening mouth of the opening; an optical element chip provided so
as to cover a second opening mouth of the opening and including an
optical element for emitting or receiving light in a surface of the
optical element chip facing the translucent member; a conductive
portion provided so as to have part buried in the device substrate
and including first terminal portions each of which is electrically
connected to the optical element and second terminal portions each
of which is electrically connected to a wiring board; and an
encapsulant for encapsulating an electrical connection portion of
the optical element and each of the first terminal portions. In the
third optical device, an orientation-indicating through hole for
indicating a position orientation of the second terminal portions
in the device substrate is formed. In the third optical device, it
is preferable that the orientation-indicating through hole is
formed in some other part of the device substrate than parts
thereof in which the second terminal portions are formed and the
encapsulant member is provided.
[0023] An "opening extending substantially in the vertical
direction with respect to a surface of the device substrate and
passing through the device substrate" in each of the first, second
and third optical devices means to be not only an opening extending
in the vertical direction in a strict mathematical sense but also
an opening extending in the direction slightly shifted from the
vertical direction in a strict mathematical sense.
[0024] Moreover, "translucent" of the translucent member in each of
the first, second and third optical devices means to be being
capable of transmitting light at a transmittance of 70% or more,
preferably, 80% or more and, more preferably, 90% or more.
[0025] Moreover, as the "optical element" in each of the first,
second and third optical devices, a solid state imaging element
such as a CCD (charge-coupled device), a set of a plurality of
light receiving elements discretely arranged, a light emitting
element or the like may be used. When the optical element is a
solid state imaging element, the optical device serves as a solid
state imaging device. When the optical element is a light receiving
element or a light emitting element, the optical device serves as a
light receiving device or a light emitting device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIGS. 1A and 1B are views illustrating the structure of an
optical device 100 according to a first embodiment of the present
invention.
[0027] FIGS. 2A and 2B are views illustrating the structure of a
device substrate 10 according to the first embodiment.
[0028] FIGS. 3A through 3F are cross-sectional views illustrating
respective steps for fabricating the optical device 100 according
to the first embodiment.
[0029] FIGS. 4A and 4B are cross-sectional views illustrating
respective part of steps for fabricating the optical device 100
according to the first embodiment.
[0030] FIG. 5 is a plan view of a device substrate 20 according to
a second embodiment of the present invention.
[0031] FIG. 6 is a plan view of a device substrate 30 according to
a third embodiment of the present invention.
[0032] FIGS. 7A and 7B are views illustrating the structure of an
optical device 400 according to a fourth embodiment of the present
invention.
[0033] FIG. 8 is a flow chart showing a method for fabricating an
optical element chip from an optical substrate according to the
fourth embodiment.
[0034] FIGS. 9A through 9F are cross-sectional views illustrating
respective steps for fabricating the optical device 400 according
to the fourth embodiment.
[0035] FIG. 10 is a plan view of a device substrate 50 according to
a fifth embodiment of the present invention.
[0036] FIG. 11 is a cross-sectional view of a CCD package chip 90
in a known example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Hereinafter, embodiments of the present invention will be
described in detail with reference to the accompanying drawings.
Note that the present invention is not limited to the following
embodiments.
First Embodiment
[0038] In a first embodiment, the structure of an optical device
100 and a method for fabricating the optical device 100 will be
described with reference to FIGS. 1, 2, 3 and 4. FIGS. 1A and 1B
are views illustrating the structure of the optical device 100.
FIG. 2 is a view illustrating the structure of a device substrate
10. FIGS. 3A through 3F are cross-sectional views illustrating
respective steps for fabricating the optical device 100. And FIG. 4
is a cross-sectional view illustrating part of steps for
fabricating the optical device 100. Moreover, FIG. 1B is a view
illustrating a back side of the optical device 100. FIG. 1A is a
cross-sectional view taken along the line IA-IA of FIG. 1B. FIG. 2A
is also a cross-sectional view taken along the line IA-IA of FIG.
1B. And FIG. 1B is a plan view illustrating a surface of the device
substrate 10 having a first opening mouth 3.
[0039] --Structure of Optical Device 100--
[0040] First, the structure of the optical device 100 will be
described.
[0041] As shown in FIGS. 1A and 1B, the optical device 100 of this
embodiment includes the device substrate 10 in which an opening 2
is formed so as to extend substantially in the vertical direction
to surfaces of the device substrate 10 and pass through the device
substrate 10, a translucent member 6 provided so as to cover a
first opening mouth 3 (shown in FIG. 2A) of the opening 2, an
optical element chip 5 which is provided so as to cover a second
opening mouth 4 (shown in FIG. 2A) of the opening 2 and in which an
optical element for emitting/receiving light is formed in a surface
of the optical element chip 5 so as to face the translucent member
6, and conductive portions 14 each having part buried in the device
substrate 10. In this case, the translucent member 6 is preferably
formed of a material such as glass having a transmittance of at
least 70% or more.
[0042] In the optical element chip 5, as an optical element, formed
is one of the following optical elements: a solid state imaging
element such as a CCD, a set of a plurality of light receiving
elements discretely arranged, and a light emitting element. A
surface (optical element formation surface) 5a of the optical
element chip 5 in which the optical element is formed faces the
translucent member 6. Thus, when an optical element for emitting
light is formed in the optical element chip 5, light emitted from
the optical element passes through the opening 2 in the device
substrate 10, transmits through the translucent member 6 and is
output to the outside of the optical device 100. When an optical
element for receiving light is formed in the optical element chip
5, light transmits through the translucent member 6, is input into
the optical device 100, passes through the opening 2 in the device
substrate 10 and then is received by the optical element. Moreover,
electrode pads 5b are provided so as to be electrically connected
to an outer peripheral portion of the optical element formation
surface 5a and bumps (protruding electrodes) 8 are provided so that
each of the bumps 8 is electrically connected to a surface of an
associated one of the electrode pads 5b.
[0043] The device substrate 10 is formed of a plastic resin such as
an epoxy resin or ceramic. Moreover, two position defining holes
10a uses as references for defining a center position of the
optical device 100 in the X and Y directions are formed. The two
position defining holes 10a are used as reference positions in
mounting the optical element chip 5 in fabrication process steps
for the optical device 100 or references for defining a location in
which a cylindrical mirror storing an optical system such as a lens
is installed when the cylindrical mirror is installed in an optical
apparatus. In this case, if two or more holes 10a for position
defining are provided, the center position of the optical device
100 can be found. Therefore, it is preferable that two or more
position defining holes 1a are provided. As shown in FIG. 2A, the
opening 2 in the device substrate 10 is a three dimensional space
and, more specifically, is a pillar-shaped space having the first
opening mouth 3 as one of the bases in one surface of the device
substrate 10 covered by the translucent member 6 and the second
opening mouth 4 as the other one of the bases in the other surface
of the device substrate 10 covered by the optical element chip 5.
The outline shape of the first opening mouth 3 and the outline
shape of the second opening mouth 4 are substantially the same. The
outline shape of the first opening mouth 3 will be described
later.
[0044] Each of the conductive portions 14 includes an interconnect
portion 12 buried in the device substrate 10 and a second terminal
portion 13 which is in contact with a surface of the device
substrate 10 and electrically connected to a wiring board.
[0045] The interconnect portion 12 includes a main interconnect
portion extending substantially in parallel to the surfaces of the
device substrate 10 and terminal portions each of which is provided
so as to extend from the main interconnect portion toward the
surface of the device substrate 10 in which the second opening
mouth 4 is formed. The terminal portions are an internal terminal
portion (first terminal portion) 12a and an external terminal
portion 12b, and are provided in this order so that the external
terminal portion 12b is more distant from the opening 2 than the
internal terminal portion 12a. One edge portion of each of the
terminal portions 12a and 12b is formed as a unit with the main
interconnect portion. The other edge portion of the internal
terminal portion 12a is electrically connected with an associated
one of the bumps 8 and the other edge portion of the external
terminal portion 12b is electrically connected to the second
terminal portion 13.
[0046] As for the second terminal portion 13, a plurality of second
terminal portions 13 are provided around an perimeter of the
surface of the device substrate 10 having the second opening mouth
4 so as to be arranged symmetrically with respect to a center point
of the device substrate 10 in the surface thereof having the second
opening mouth 4. The second terminal portions 13 have different
functions from one another. For example, some of the second
terminal portions 13 serve as input terminals for inputting a
voltage to the optical element, others of the second terminal
portions 13 serve as output terminals for outputting a voltage from
the second terminal to the wiring board, and still others of the
second terminal portions 13 serve as power supply source
terminals.
[0047] An electrical connection portion between the optical element
and the internal terminal portion 12a is encapsulated by a first
sealing resin (encapsulant) 7. Thus, a void between the optical
element chip 5 and the device substrate 10 is encapsulated by the
first sealing resin 7, so that the optical element chip 5 is fixed
to the device substrate 10. Moreover, a void between the
translucent member 6 and the device substrate 10 is encapsulated by
a second sealing resin 15, so that the translucent member 6 is
fixed to the device substrate 10. Moreover, the first sealing resin
7 and the second sealing resin 15 prevent invasion of unnecessary
light and moisture in the air into the inside of the optical device
100. Therefore, the optical device 100 has a more excellent
performance than that of an optical device in which an electrical
connection portion and the like are not encapsulated.
[0048] The shape of the opening 2 in the device substrate 10, which
is a feature of this embodiment, will be described. An outline
shape of the first opening mouth 3 is point-asymmetrical with
respect to an approximate center point 3b of the first opening
mouth 3. Specifically, the outline of the first opening mouth 3 has
a shape obtained by cutting off a portion including one of four
vertexes of a rectangle (hereinafter part 3a of the outline of the
first opening mouth from which the portion including the vertex has
been cut off will be referred to as a "point-asymmetrical portion
3a"). In other words, the outline shape of the first opening mouth
3 is a point-asymmetrical pentagon. Two of five interior angles of
the pentagon are obtuse angles and the other three are right
angles. The translucent member 6 covering the first opening mouth 3
has a transmittance of 70% or more. Therefore, when the optical
device 100 is observed through the translucent member 6, the
point-asymmetrical portion 3a can be visually identified. For
example, if the opening 2 is formed so that the point-asymmetrical
potion 3a is located in part of the outline of the first opening
mouth 3 which is the closest to one of the second terminal portions
13 (e.g., one of the second terminal portions 13 located closest to
a first pin) having a specific function, the position of the second
terminal portion 13 can be identified by observing the optical
device 100 through the translucent member 6 from the first opening
mouth 3 side to visually identify the point-asymmetrical portion
3a. Thus, the point-asymmetrical portion 3a has the function of
indicating the position orientation of the second terminal portions
13 in the device substrate 10. Accordingly, by observing the
optical device 100 through the translucent member 6, for example,
the position of one of the second terminal portions 13 serving as
an input terminal and the position of another of the second
terminal portions 13 serving as an output terminal can be
identified.
[0049] Hereinafter, the reason why the outline shape of the first
opening mouth 3 is point-asymmetrical with respect to the
approximate center point 3b of the first opening mouth 3 will be
described.
[0050] In recent years, miniaturization of video cameras, digital
cameras, digital still cameras and the like has been desired and,
accordingly, reduction in the size of an optical device included in
such equipment is required. As shown in FIG. 1A, the size of an
optical device is defined depending on the size of a device
substrate. Therefore, the size of the device substrate is reduced,
thereby allowing miniaturization of the optical device.
[0051] On the other hand, if the size of a device substrate is
reduced too much, the number of second terminal portions provided
in a surface of the device substrate is reduced. As has been
described, the second terminal portions have different functions
from one another, and if the number of the second terminal portions
is reduced, an optical device or the like can not exhibit its
desired function. Therefore, it is preferable that the size of the
device substrate is sufficiently large so that a sufficient number
of second terminal portions can be provided on the device substrate
and is sufficiently small so that miniaturization of a video camera
or the like can be achieved.
[0052] Furthermore, it is preferable that the position orientation
of the second terminal portions can be identified by observing the
optical device. Since the second terminal portions have different
functions from one another, merely mounting the optical device on a
wiring board might cause a situation where the optical element of
the optical device can not emit desired light or perform image
processing to received light. To avoid such a situation, it is
preferable that the position orientation of one of the second
terminal portions having a specific function can be identified
through visual identification by observation of the optical device.
As a possible technique for allowing the visual identification of
the position orientation of one of the second terminal portions
having a specific function, for example, use of a device substrate
having a shape obtained by linearly cutting off a portion including
one of vertexes of the device substrate located closest to one of
the second terminal portions having a specific function or a device
substrate in which marking is given around one of the second
terminal portions having a specific function is considered. And, an
optical device including such a device substrate can be mounted on
a wiring board in consideration of a position orientation of
interconnects in an optical device chip. Thus, the situation
described above can be avoided.
[0053] However, when either one of the above-described two device
substrates is used, the following problems arise. First, a problem
that arises when the device substrate having a shape obtained by
linearly cutting off a portion including one of vertexes of the
substrate is used will be described. With use of the device
substrate having one of the above-described shapes, positions of
ones of the second terminal portions around the cut-off portion has
to be changed. Accordingly, the positions of the internal terminal
portions and the second terminal portions in the device substrate
are limited. Moreover, when a cylindrical mirror or the like is
installed in an optical apparatus in which an optical device having
the device substrate is mounted on a wiring board, the outside
shape of the device substrate is limited because the portion
including one of vertexes of the device substrate is linearly cut
off. Therefore this technique is not preferable.
[0054] With use of the device substrate in which marking is given
around one of the second terminal portions having a specific
function, a space for marking is required and therefore the size of
the device substrate can not be reduced. Accordingly, the optical
device can not be miniaturized. Moreover, if projections and
depressions are formed in a surface of the device substrate to give
marking onto the surface of the device substrate, level differences
are generated in the surface of the device substrate. Therefore,
the degree of flatness of the optical device including the device
substrate is reduced, and when a cylindrical mirror is installed in
the optical apparatus in which the optical device is mounted on a
wiring board, a tilt generated in installing the cylindrical mirror
is influenced.
[0055] However, in the optical device 100 of this embodiment, the
point-asymmetrical portion 3a is part of the outline of the first
opening mouth 3 and therefore the positions of the internal
terminal portions 12a and the second terminal portions 13 do not
have to be changed. Also, almost no space is required for the
point-asymmetrical portion 3a and thus the device substrate 10 can
be miniaturized. As a result, miniaturization of the optical device
100 can be achieved. Furthermore, the device substrate 10 is formed
so as to have a rectangular shape and also no level difference in
the surface. Therefore, when a cylindrical mirror or the like is
installed in an optical apparatus in which the optical device 100
is mounted on a wiring board, the outside shape of the device
substrate is not regulated and a tilt generated in mounting the
cylindrical mirror is not influenced.
[0056] Furthermore, the point-asymmetrical portion 3a has the
function of indicating the position orientation of the second
terminal portions 13 in the device substrate 10. Thus, by observing
the optical device 100 through the translucent member 6, for
example, the position of one of the second terminal portions 13
serving as an input terminal and the position of another of the
second terminal portions 13 serving as an output terminal can be
identified. Accordingly, if the optical device 100 is observed
through the translucent member 6 from the first opening mouth 3
side in the device substrate 10 and the optical device 100 is
mounted on a wiring board, for example, the optical device 100 can
be mounted so that one of the second terminal portions 13 serving
as an input terminal matched in position with a connection terminal
provided on the wiring board and corresponding to the input
terminal. Therefore, a situation where a voltage is not applied to
the optical element or a situation where an excessive voltage is
applied can be avoided, and thus the optical element can emit
desired light and perform image processing of received light.
[0057] --Process Steps for Fabricating Optical Device 100--
[0058] First, as shown in FIG. 3A, a lead frame 52 in which an
interconnect pattern is formed is placed on a sealing tape 21. In
this case, half-etching or stamping is performed so that a concave
portion is formed so as to be located under most part of the lead
frame 52 and only parts of the lead frame 52 to be an internal
terminal portion 12a and an external terminal portion 12b are left
as protruding potions extending downward from a bottom surface of
the concave portion. Thus, a lead frame member in which the lead
frame 52 is provided on the sealing tape 21 is formed. The lead
frame 52 is divided into interconnect portions 12 in a later
process step.
[0059] Next, as shown in FIG. 3B, molding is performed. The details
of the molding are shown in FIGS. 4A and 4B. In this process step,
first, the lead frame member described above is placed in a molding
die 31. In this case, the molding die 31 is shown as a single piece
member in FIG. 4A, but the molding die 31 actually includes a lower
molding die and an upper molding die covering the lower molding die
each of which is formed of an approximately flat plate. The upper
molding die includes a die cavity 31a, a divider portion 31b and
pin members 31c in one surface of the upper molding die. Each of
the pin members 31c is provided in the die cavity 31a. The divider
portion 31b is part to be an opening 2 and has a pillar shape with
bases having an approximate rectangular shape obtained by linearly
cutting off a portion including a vertex linearly. Moreover, the
pin members 31c are parts to be position defining holes 10a. With
the lead frame 52 facing upward, the lead frame member is placed on
a surface of the lower molding die. Then, the upper molding die is
turned so that a surface thereof on which the die cavity 31a are
formed faces downward and then placed over the lead frame member so
as to cover the lead frame member. Thus, the die cavity 31a is
covered by the lead frame member and the lower molding die. Then,
as shown in FIG. 4B, a plastic resin such as an epoxy resin is
filled in the die cavity 31a. Thereafter, when the plastic resin is
anchored, the molding die is removed and the sealing tape 21 is
peeled off from the lead frame member. Thus, a molded body 11 in
which the lead frame 52 is buried is obtained. In this case, the
internal terminal portions 12a and the external terminal portions
12b are exposed at one surface of the molded body 11.
[0060] Although not shown in the drawings, the molded body 11 is
placed so that the exposed surfaces of the internal terminal
portions 12a and the external terminal portions 12b face upward.
Then, a boundary portion between optical device formation regions
located adjacent to each other is cut at the center of a cutting
portion, thereby dividing the molded body 11 into individual
optical devices. Thus, device substrates 10 including the
interconnect portions 12 buried therein, respectively, are
obtained.
[0061] Subsequently, in the process step of FIG. 3C, a plurality of
second terminal portions 13 are provided on the exposed surfaces of
the external terminal portion 12b, respectively. In this case, it
is preferable that the second terminal portions 13 are provided so
as to be point symmetrical with respect to a substantially center
point of a device substrate 10.
[0062] Thereafter, in the process step of FIG. 3D, with the optical
element formation surface 5a of the optical element chip 5 facing
downward, the optical element chip 5 is mounted so as to cover an
opening (second opening mouth) in the same surface as the exposed
surface of each of the internal terminal portions 12a and the
external terminal portions 12b. In this case, bumps 8 are formed on
the exposed surface of the internal terminal portions 12a,
respectively, and then electrode pads 5b of the optical element
chip 5 are provided on the bumps 8, respectively, so that each of
the bumps 8 is flip-chip connected to an associated one of the
electrode pads 5b. Note that in placing the optical element chip 5,
if the position of the optical element chip 5 is defined using the
position defining holes 10a provided in the device substrate 10 as
references, the optical element chip 5 can be placed in a desired
orientation with respect to the device substrate 10.
[0063] Then, in the process step of FIG. 3E, the internal terminal
portion 12a, the bumps 8 and the electrode pads 5b are encapsulated
using a first sealing resin 7. Thus, an electrical connection
portion between the optical device and each of the interconnect
portions 12, i.e., a void between the optical element chip 5 and a
peripheral portion of the opening 2 is encapsulated by the first
sealing resin 7.
[0064] Then, in the process step of FIG. 3F, a molded body obtained
in the process step of FIG. 3E is placed so that the optical
element chip 5 is placed at the bottom and the translucent member 6
is mounted so as to cover a surface (first opening mouth) of the
opening 2 which is not covered. A void between the translucent
member 6 and the peripheral portion of the opening 2 is
encapsulated using a second sealing resin 15. Thus, the optical
device 100 of this embodiment can be fabricated.
[0065] When an optical device is fabricated using a device
substrate including an opening of which a first opening mouth has a
point symmetrical outline shape with respect to the substantially
center point of the opening, a divider portion in an upper molding
die used in the above-described molding process step has a pillar
shape with a rectangular base. On the other hand, when an optical
device is fabricated using the device substrate 10 of this
embodiment, the divider portion 31b in the upper molding die used
in the molding process step has a pillar shape with a base having a
substantially rectangular shape obtained by linearly cutting off a
portion including a vertex. That is, if the shape of a base of the
divider portion of the upper molding die is changed to a
substantially rectangular shape obtained by linearly cutting off a
portion including a vertex, the optical device 100 in which the
position orientation of the second terminal portions 13 in the
device substrate 10 can be identified by observing the second
terminal portions 13 through the translucent member 6.
Second Embodiment
[0066] In a second embodiment, the structure of a device substrate
20 will be described with reference to FIG. 5. Note that FIG. 5 is
a plan view illustrating a surface of the device substrate 20
having a first opening mouth.
[0067] According to this embodiment, an optical device is obtained
by replacing the device substrate 10 of the optical device shown in
FIGS. 1A and 1B with the device substrate 20. Other than that, the
structure of the optical device and a method for fabricating the
optical device according this embodiment are the same as those of
the first embodiment and therefore the description thereof will be
omitted.
[0068] The device substrate 20 of this embodiment and the device
substrate 10 of the first embodiment are different from each other
only in the outline shape of an opening. The outline of a first
opening mouth 23 in the device substrate 20 of this embodiment has
a shape obtained by roundly cutting off a portion including one of
vertexes of a rectangle (hereinafter part 23a of the outline of the
first opening mouth 23 from which the portion including the vertex
has been roundly cut off will referred to as a "point asymmetry
portion 23a). In other words, the outline shape of the first
opening mouth 23 is a shape having a circumference with part
including one of four vertexes of a rectangle and having an
arc-shape. In another way, the outline shape of the first opening
mouth 23 can be described as a shape having a circumference with
part including one of four vertexes of a rectangle and formed into
a rounded corner. If an opening is formed so that the
point-asymmetrical portion 23a is located in part of the outline of
the first opening mouth 23 located closest to one of second
terminal portions having a specific function, the position of one
of the second terminal portions having a specific function can be
identified through visual identification by observing the optical
device from the first opening mouth 23 side through a translucent
member. Therefore, the point-asymmetrical portion 23a has the
function of indicating the position orientation of the second
terminal portions in the device substrate 20. Accordingly, the
optical device of this embodiment exhibits approximately the same
effects as those of the optical device 100 of the optical
device.
[0069] Note that a divider portion of an upper molding die used in
the step of molding in the method for fabricating an optical device
according to this embodiment has a pillar shape with a base having
an approximately rectangular shape obtained by roundly cutting off
a portion including a vertex.
Third Embodiment
[0070] In a third embodiment, the structure of a device substrate
30 will be described with reference to FIG. 6. FIG. 6 is a view
illustrating a back surface of an optical device.
[0071] According to this embodiment, an optical device is obtained
by replacing the optical element chip 5 and the device substrate 10
of the optical device shown in FIGS. 1A and 1B with an optical
element chip 35 and the device substrate 30, respectively. Other
than that, the structure of the optical device and a method for
fabricating the optical device according to this embodiment are the
same as those of the first embodiment and therefore the description
thereof will be omitted.
[0072] In the device substrate 30 of this embodiment, the outline
shape of a first opening mouth is a rectangle. Thus, the position
orientation of second terminal portions 13 can not be identified
through visual identification by observing the device substrate 30
through a translucent member. However, the position orientation of
second terminal portions 13 in the device substrate 30 can be
identified through visual identification in a different manner
because an optical element chip 35 has a characteristic described
below. Hereinafter, the optical element chip 35 of this embodiment
will be described.
[0073] In the optical element chip 35, as shown in FIG. 6, an
orientation-indicating marker 35a having a circular shape and
indicating the position orientation of the second terminal portions
13 in the device substrate 30 is formed in vicinity of a vertex in
the back surface of the optical element chip 35 (having a
rectangular shape). For example, the orientation-indicating marker
35a is provided in part of the back surface of the optical element
chip 35 located close to one of the second terminal portions 13
having a specific function. Thus, the position of one of the second
terminal portions 13 having a specific function can be identified
through visual identification by observing the back surface of the
optical device. Therefore, the optical device of this embodiment
exhibits approximately the same effects as those of the optical
device 100 described in the first embodiment.
[0074] It is preferable that the orientation-indicating marker 35a
is given by a known marking method. Also, the shape of the marker
35a is not limited to a circular shape but may be a polygonal shape
or the like.
[0075] Moreover, a divider portion of an upper molding die used in
the step of molding in the method for fabricating an optical device
according to this embodiment has a pillar shape with a rectangular
base.
Fourth Embodiment
[0076] In a fourth embodiment, the structure of an optical device
400, a method for testing the performance of an optical device
chip, and a method for fabricating the optical device 400 will be
described with reference to FIGS. 7A and 7B, FIG. 8 and FIGS. 9A
through 9F. FIGS. 7A and 7B are views illustrating the structure of
the optical device 400. FIG. 8 is a flow chart showing a method for
fabricating an optical element chip from an optical substrate.
FIGS. 9A through 9F are cross-sectional views illustrating
respective steps for fabricating the optical device 400. Also, FIG.
7B is a view illustrating a back surface of the optical device 400.
And FIG. 7A is a cross-sectional view taken along the line
VIIA-VIIA of FIG. 7B.
[0077] As shown in FIGS. 7A and 7B, the optical device 400 of this
embodiment is obtained by replacing the optical element chip 5 and
the device substrate 10 of the optical device shown in FIGS. 1A and
1B with an optical element chip 45 and a device substrate 40
described below, respectively. Other than that, the structure of
the optical device and a method for fabricating the optical device
according to this embodiment are the same as those of the first
embodiment and therefore the description thereof will be
omitted.
[0078] The device substrate 40 of this embodiment is approximately
the same as the device substrate 30 of the third embodiment.
Therefore, the position orientation of second terminal portions 13
in the device substrate 40 can not be identified through visual
identification by observing the device substrate 40 through a
translucent member. However, the position orientation of second
terminal portions 13 in the device substrate 40 can be identified
through visual identification in a different manner because an
optical element chip 45 has a characteristic described below.
Hereinafter, the optical element chip 45 of this embodiment will be
described.
[0079] As shown in FIG. 7B, in the optical element chip 45, an
orientation-indicating marker portion 45a including a character of
A is formed on a back surface of the optical element chip 45. The
orientation-indicating marker portion 45a indicates the position
orientation of the second terminal portions 13 in the same manner
as the orientation-indicating marker 35a of the third embodiment.
For example, the orientation-indicating marker 45a is formed so
that one of the second terminal portions 13 having a specific
function is located on the left-hand side of the
orientation-indicating marker 45a. Thus, the position of one of the
second terminal portions 13 having a specific function can be
identified through visual identification by observing the back
surface of the optical device 400. Therefore, the optical device
400 of this embodiment exhibits approximately the same effects as
those of the optical device 100 described in the first
embodiment.
[0080] As in the third embodiment, it is preferable that the
orientation-indicating marker 45a is given by a known marking
method. Moreover, a divider portion of an upper molding die used in
the step of molding in the method for fabricating an optical device
according to this embodiment has a pillar shape with a rectangular
base.
[0081] Furthermore, if the orientation-indicating marker 45a is
formed on a back surface of each optical element chip while the
optical element chip is still in a wafer state, not only the
orientation of the optical device 400 can be identified but also
the following effects can be achieved.
[0082] In general, an optical element chip is fabricated by
dividing a substrate (such as an optical substrate and a wafer) in
which a plurality of optical element chips are formed so as to be
arranged side by side so that the individual optical element chips
are separated from one another. Each of the optical element chips
is electrically tested before the wafer is diced. Then, by using
only ones of the optical element chips which have been judged as
non-defective chips in the test, optical device are fabricated and
final products such as a video camera are produced. Thereafter,
optical test for the final products is performed and only final
products which have been judged as non-defective products in the
optical test are distributed to the market.
[0083] Each of the final products to which the optical test is
performed includes only an optical element chip judged as a good
optical element chip in the electric test. However, the optical
performance of each optical element chip can not be tested while
the optical element chip is still in a wafer state, and therefore,
some of final products which have been produced using optical
element chips judged as good optical element chips in the electric
test are judged as defectives in the optical test. The final
products judged as detectives can not be distributed to the market,
so that production costs and time for the defective final products
are wasted.
[0084] The above-described inconvenience occurs because results of
an optical test can not be fed back to process steps for
fabricating an optical device.
[0085] In many cases, a wafer is formed by repeating layer
stacking, etching and the like, and a series of such process steps
are performed using an apparatus and a plurality of optical element
chips are fabricated at a time. In many cases, a fabrication
apparatus includes a plurality of members having the same function,
so that optical element chips located in the same location in
different wafers have approximately the same performance.
Therefore, even after dicing a wafer, if the position of each
optical element chip in the wafer can be identified, results of an
optical test can be fed back to process steps for fabricating an
optical device. In view of this point, the present inventors have
invented a method for tracing the dependency on a pattern
repeatedly caused by a defect of the pattern, the dependency on a
difference in equipment and variations in conditions. The method
will be described with reference to FIG. 8. Hereinafter, a "test
use" item means to be an item used for feedback of results of an
optical test to process steps for fabricating an optical device.
The following optical test is performed not only to "test use final
products" but also "final products".
[0086] First, in the wafer fabrication step S401, a plurality of
wafers, each including optical element chips formed in a surface
thereof, are fabricated using the same method and the same
fabrication apparatus. In this case, one of the wafers is used as a
test use wafer for checking optical performances of the optical
element chips. Then, the process proceeds with the grinding step
S402. Note that in the following steps, it is preferable that the
operation of each process step is performed to all of the wafers
obtained in this step unless specifically stated.
[0087] In the grinding step S402, a surface (back surface) of a
wafer located in the other side to a surface thereof in which the
optical element chips are formed is grinded. Then, the process
proceeds with the electric test step S403.
[0088] In the electric test step S403, an electric test is
performed to each of the optical element chips formed on the wafer.
Specifically, first, a test use signal waveform is input to each of
the optical element chips and an output waveform from each of the
optical element chips corresponding to the input waveform is
detected. Then, the detected output waveform is compared to an
ideal output waveform. If the comparison between the waveforms
shows the output waveforms have approximately the same shape, it is
judged that the optical element chip is good. If the comparison
shows that the output waveforms have different shapes, it is judged
that the optical element chip is defective. Ones of the optical
element chips judged as defectives in the comparison are labeled as
defectives on a surface of each of the optical element chips. Then,
the process proceeds with the marking step S404.
[0089] In the marking step S404, a marker for indicating the
position of the optical element chips in a wafer is given on a back
surface of each optical element chip. In this case, it is
preferable that the marker is given by a known marking method.
Moreover, it is preferable that the marker is point-asymmetrical
with respect to a center point of the back surface of the optical
element chip. Then, the process step proceeds with the dicing step
S405.
[0090] In the dicing step S405, a wafer is diced. Thus, a large
number of optical element chips can be fabricated from a single
wafer. Note that an optical element chip labeled as a defective on
a surface thereof in the test step S402 is discarded after this
step. Then, the process proceeds with the product fabrication step
S406.
[0091] In the product fabrication step S406, test use optical
device, optical apparatus and final product for checking the
optical performance of an optical element chip are produced.
Specifically, first, using a test use element chip obtained by
dicing a test use wafer, a test use optical device is fabricated
according to fabrication process steps shown in FIGS. 9A through
9F. In this case, the process steps shown in FIGS. 9A through 9F
are approximately the same as those described in the first
embodiment (FIGS. 3A through 3F) but are different from the
fabrication process steps of the first embodiment in that an upper
molding die with a rectangular cross-sectional shape in the molding
step and an optical element chip 45 in which a marker is given on a
back surface thereof is used. Thereafter, the test use optical
device is mounted on a wiring board to fabricate a test use optical
apparatus. Then, a cylindrical mirror is installed in the test use
optical apparatus, thereby fabricating a test use final product
such as a video camera. Then, the process proceeds with the optical
test step S407.
[0092] In the optical test step S407, the test use final product is
optically tested. Specifically, an electrical characteristic test
and a visual identification test for image are performed to judge
whether the test use final product is good or defective.
Thereafter, the process proceeds with the analysis step S408.
[0093] In the analysis step S408, the relationship between the
optical performance of each optical element chip and the position
of the optical element chip in the wafer is examined. The optical
performance of each optical element chip can be shown from test
results in the optical test step S407. Specifically, in the optical
test step S407, it can be assumed that an optical element chip
mounted on a test use final product judged as good has an excellent
optical performance and an optical element chip mounted on a test
use final product judged as a defective has a poor optical
performance. Moreover, the position of each optical chip in the
wafer can be identified by observing the back surface of the test
use optical device. Also, as has been described above, the same
relationship is maintained between the optical performance of each
optical element chip and the position of the optical element chip
in a wafer even on a different wafer, and thus it is possible to
assume, using this relationship, which optical element chip located
where in the wafer can be used to fabricate an optical device and
the like and then to fabricate a product with an excellent optical
performance. Accordingly, if an optical product is fabricated
according to the method of this embodiment, the above-described
problems can be eliminated.
[0094] Thus, a method for testing the performance of an optical
element chip according to this embodiment preferably has one of
structures described below.
[0095] First, according to a first structure of the method for
testing the performance of an optical element chip, the method
includes the step of fabricating wafers including a test use wafer
in which a plurality of optical element chips are formed on a
surface thereof and which is for checking the optical performance
of each optical element chip, the grinding step of grinding an
opposite surface (back surface) of each of the wafers from a
principal surface thereof, the electrical test step of performing
an electrical test to each optical element chip, the marking step
of giving a marker for indicating the position of optical element
chips in each of the wafers, the dicing step of dicing each of the
wafers after the marking step, the step of fabricating test use
optical devices using test use optical element chips obtained by
dicing the test use wafer, the step of fabricating test use optical
apparatuses by mounting each of the test use optical devices on a
wiring board, the step of fabricating test use final products by
installing an optical member such as a cylindrical mirror in each
of the test use optical apparatuses, the optical test step of
performing an optical test to each of the test use final products,
the analysis step of examining the relationship between the
position of each test use optical element chip in the test use
wafer and the optical performance of the test use optical element
chip, based on results of the optical test, and the step of
selecting, after the analysis step, only ones of the optical
element chips indicating a more excellent optical performance than
a certain optical performance from the optical element chips
obtained by dicing the wafers other than the test use wafer, based
on the relationship between the position of each optical element
chip in the test use wafer and the optical element of the optical
element chip, to fabricate an optical device.
[0096] To describe the first structure in other words, first, test
use final products are fabricated using test use optical element
chips obtained by dicing a test use wafer, and then an optical test
is performed to the test use final product. Next, from a result of
the optical test, the position of the optical element chips in each
wafer is related to the optical performances of the optical element
chips. Subsequently, based on the relationship, products with an
excellent optical performance are fabricated using optical element
chips obtained by dicing another wafer and assumed to have an
excellent optical performance.
[0097] The method for testing the performance test of an optical
element chip according to this embodiment may also have the
following structure.
[0098] According to a second structure of the method the method for
testing the performance of an optical element chip, the method
includes the step of fabricating a test use wafer in which a
plurality of optical element chips are formed on a surface thereof
and which is for checking the optical performance of each of the
optical element chips, the grinding step of grinding an opposite
surface (back surface) of the test use wafer from a principal
surface thereof, the electrical test step of performing an
electrical test to each of the optical element chips, the marking
step of giving on a back surface of each of the optical element
chips, a marker for indicating the position of the optical element
chips in the test use wafer, the dicing step of dicing the test use
wafer after the marking step, the step of fabricating test use
optical devices using test use optical element chips obtained by
dicing the test use wafer, the step of fabricating test use optical
apparatuses by mounting each of the test use optical devices on a
wiring board, the optical test step of performing an optical test
to each of the test use optical apparatuses, the analysis step of
examining the relationship between the position of each of the test
use optical element chips in the test use wafer and the optical
performance of the test use optical element chip, based on results
of the optical test, the step of repairing, after the analysis
step, defective part in an apparatus for fabricating the optical
element chips, based on the relationship between the position of
each of the optical element chips in the test use wafer and the
optical performance of the optical element chip, the step of
fabricating wafers using the apparatus, and the step of fabricating
optical products using optical element chips obtained by dicing
each of the wafers.
[0099] The second structure is different from the first structure
in that the second structure includes the step of repairing an
apparatus for fabricating optical element chips. Because the second
structure includes this step, more optical element chips with an
excellent optical performance can be fabricated when wafers are
fabricated using the second structure than when wafers are
fabricated using the first structure. Thus, a better yield of final
products can be achieved with the second structure than the first
structure. Therefore, the second structure is more preferable than
the first structure.
[0100] Moreover, a marker given in the marking step is preferably a
point-asymmetrical symbol, an asymmetrical character or a
combination of a symbol and a character. Thus, not only the
above-described problems can be eliminated but also the position
orientation of the second terminal portions 13 in the optical
device 400 including the optical element chip 45 can be preferably
identified.
[0101] Note that the orientation-indicating marker 45a in this
embodiment may be some other alphabet than "A", a kana (Japanese
syllabic script), a kanji (Japanese Chinese-derived character) or a
numeric character. Moreover, for example, the
orientation-indicating marker 45a may be a mixture of an alphabet
and a kana. Furthermore, assume that the orientation-indicating
marker 45a is formed of a plurality of characters and symbols.
Then, even if one of the characters and symbols is point
symmetrical, the orientation-indicating marker 45a can be used as
long as the orientation-indicating marker 45a as a whole is
point-asymmetrical with respect to the approximate center of the
optical element chip 45.
[0102] Moreover, in the method for testing a performance of an
optical element chip according to this embodiment, first, the test
step S402 is performed and then the grinding step S401, the marking
step S403, the dicing step S404 and the selection step S405 may be
performed in this order. Moreover, a result of a good/defective
test may be labeled on a back surface of the optical element chip
45.
[0103] An optical chip judged to be optically good in the method
for testing the performance of an optical element chip according to
this embodiment can be used not only for the optical device 400 of
FIG. 7 but also as an optical element chip in which a solid state
imaging element, such as a CCD or a CMOS, installed in an image
sensor, an optical element chip in which a receiving element
installed in a laser or the like.
Fifth Embodiment
[0104] In a fifth embodiment according to the present invention,
the structure of a device substrate 50 will be described with
reference to FIG. 10. FIG. 10 is a view illustrating a back surface
of the device substrate 50.
[0105] An optical device in this embodiment is an optical device
obtained by replacing the device substrate 10 of the optical device
shown in FIGS. 1A and 1B with the device substrate 50. Other than
that, the structure of the optical device and a method for
fabricating the optical device according to this embodiment are the
same as those of the first embodiment and therefore the description
thereof will be omitted.
[0106] In the device substrate 50 of this embodiment, the outline
shape of a first opening mouth is a rectangle. Thus, the position
orientation of the second terminal portions 13 in the device
substrate 50 can not be identified through visual identification by
observing the device substrate through a translucent member.
However, the position orientation of second terminal portions 13 in
the device substrate 50 can be identified through visual
identification in a different manner because the device substrate
50 has a characteristic described below. Hereinafter, the device
substrate 50 of this embodiment will be described.
[0107] In the device substrate 50, the position defining holes 50a
described in the first embodiment and an orientation-indicating
through hole 50b for indicating the position orientation of the
second terminal portions 13 in the device substrate 50 are formed.
The orientation-indicating through hole 50b is formed in part of
the device substrate 50 located close to one of the second terminal
portions 13 having a specific function. Thus, one of the second
terminal portions 13 having a specific function can be identified
through visual identification by visually observing the optical
device. Accordingly, the optical device of this embodiment exhibits
approximately the same effects of those of the optical device 100
of the first embodiment.
[0108] Note that the orientation-indicating through hole 50b is
preferably formed in some other part of the device substrate 50
than parts in which the second terminal portions 13 are formed and
a first sealing resin 7 is provided.
[0109] Moreover, in the molding step in the method for fabricating
an optical device according to this embodiment, three pin members
are used. Furthermore, a divider portion in an upper molding die
used in this embodiment has a pillar shape with a rectangular
base.
Other Embodiments
[0110] The present invention may be configured in the following
manner in connection with the first through fifth embodiments.
[0111] An optical device according to the present invention may be
configured so as to include the point-asymmetrical potions 3a and
23a, the orientation-indicating markers 35a and 45a, and the
orientation-indicating through hole 50b. Moreover, the optical
device may be configured so as to include the point-asymmetrical
potions 3a and 23a and the orientation-indicating markers 35a and
45a. Furthermore, the optical device may be configured so as to
include the point-asymmetrical potions 3a and 23a and the
orientation-indicating through hole 50b.
[0112] Moreover, instead of the position defining holes 10a
provided in the device substrate 10, a position defining
level-difference portion may be provided in a peripheral portion of
the device substrate 10. The position defining level-difference
portion has approximately the same function as that of the position
defining holes 10a.
[0113] Moreover, the second terminal portions 13 may be arranged so
as to be point-asymmetrical with respect to a center point in a
surface of the device substrate having the second opening mouth
4.
[0114] Moreover, in process steps for fabricating the optical
device 100, the optical element chip 5 of FIG. 3F may be divided
into individual optical devices after the optical element chip 5 of
FIG. 3F is mounted on the device substrate 10 or after the
translucent member 6 of FIG. 3G is installed on the device
substrate 10.
[0115] Moreover, although the molding step in process steps for
fabricating the optical device 100 is performed with the lead frame
52 placed on the sealing tape 21, the sealing tape 21 does not have
to be used. However, when the sealing tape 21 is used, upper and
lower surfaces of the lead frame 52 can be clamped with the upper
molding die and the lower molding die and thus the upper and lower
surfaces of the lead frame 52 can be stably kept adhered with a
surface of the molding die. That is, a plastic resin can be filled
in the molding die with the upper and lower surfaces of the lead
frame 52 adhered with the surface of the molding die. As a result,
mold flash due to molding can be effectively suppressed and a
structure in which the exposed surfaces of the internal terminal
portions 12a and the external terminal portions 12b are located at
the device substrate 10 can be obtained. Therefore, simplification
and facilitation of mounting the optical device 100 can be
achieved. For example, a soldered connection can be provided in a
simple manner when the optical device 100 is mounted on a
wiring-board.
[0116] The present invention may be configured in the following
manner in connection with the first and second embodiments.
[0117] For example, the outline of the first opening mouth may have
a shape obtained by forming an area reduced portion in at least
part of an outline of a regular polygon so that the area of the
first opening mouth is smaller than the area of the regular
polygon. Also, the outline of the first opening mouth may have a
shape with an area increase portion formed in at least part of the
outline of a regular polygon so that the area of the first opening
mouth is larger than the area of the regular polygon. Moreover, the
outline shape of the first opening mouth may be a shape obtained by
forming an area reduction portion in at least part of the outline
of a circle so that the area of the first opening mouth is smaller
than the area of the circle. Also, the outline shape of the first
opening mouth may be a shape obtained by forming an area increased
portion in at least part of the outline of a circle so that the
area of the opening at the first opening mouth is larger than the
area of the circle.
[0118] As has been described, the present invention is useful for
an optical device including an optical element in which an optical
element for emitting and receiving light is formed and an optical
apparatus including the optical device.
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