U.S. patent application number 13/224808 was filed with the patent office on 2011-12-29 for method of manufacturing a semiconductor device.
This patent application is currently assigned to RENESAS ELECTRONICS CORPORATION. Invention is credited to Hidetaka NAMBU.
Application Number | 20110318849 13/224808 |
Document ID | / |
Family ID | 40674798 |
Filed Date | 2011-12-29 |
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United States Patent
Application |
20110318849 |
Kind Code |
A1 |
NAMBU; Hidetaka |
December 29, 2011 |
METHOD OF MANUFACTURING A SEMICONDUCTOR DEVICE
Abstract
The semiconductor device of the present invention includes a
first insulating film on a substrate having a first region and a
second region, a light shielding film formed in the first region
and an interconnect film formed in the second region in the first
insulating film and a second insulating film having a first concave
portion above the light shielding film in the first region and an
interconnect hole having a via hole and a second concave portion in
the second region in the second insulating film on the first
insulating film, wherein an area of the light shielding film is
overlapping an area of the first plurality of concave portions.
Inventors: |
NAMBU; Hidetaka; (Kanagawa,
JP) |
Assignee: |
RENESAS ELECTRONICS
CORPORATION
Kanagawa
JP
|
Family ID: |
40674798 |
Appl. No.: |
13/224808 |
Filed: |
September 2, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12855906 |
Aug 13, 2010 |
8021899 |
|
|
13224808 |
|
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|
12323614 |
Nov 26, 2008 |
7800108 |
|
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12855906 |
|
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Current U.S.
Class: |
438/8 ;
257/E21.529; 257/E21.585 |
Current CPC
Class: |
H01L 21/76229
20130101 |
Class at
Publication: |
438/8 ;
257/E21.529; 257/E21.585 |
International
Class: |
H01L 21/66 20060101
H01L021/66 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 30, 2007 |
JP |
2007-309937 |
Claims
1. A method of manufacturing a semiconductor device, comprising:
providing a database including a relationship between shapes of
reference grooves and corresponding reference waveforms of light
reflected by the reference grooves; irradiating light on actual
grooves and detecting an actual waveform of light reflected by the
actual grooves; matching the actual waveform to one of the
reference waveforms in the database to determine a shape of the
actual grooves, wherein the actual grooves are formed on a light
shielding film in a test region; and wherein the actual grooves are
formed during a step in which an interconnect hole having a via
hole and a trench are formed.
2. The method of manufacturing a semiconductor device according to
claim 1, wherein the actual grooves and the trench are of
substantially equal shape.
3. The method of manufacturing a semiconductor device according to
claim 1, wherein etching conditions are adjusted based on a
difference between the shape of reference grooves and the actual
grooves.
4. The method of manufacturing a semiconductor device according to
claim 1, comprising a further step of determining whether there is
a difference between the shape of reference grooves and the actual
grooves, and excluding a wafer from further processing if said
difference is detected.
5. The method of manufacturing a semiconductor device according to
claim 1, wherein another light shielding film is formed during a
step in which the interconnect hole in the test region is
formed.
6. The method of manufacturing a semiconductor device according to
claim 1, further comprising forming a metal film that fills the
interconnect hole.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of Ser. No. 12/855,906 filed
on Aug. 13, 2010, which is a division of Ser. No. 12/323,614 filed
on Nov. 26, 2008, which claims priority to Japanese patent
application No. 2007-309937. The content of each of these
applications is hereby expressly incorporated by reference
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a semiconductor device and
a method of manufacturing a semiconductor device.
[0003] In a conventional process of manufacturing a semiconductor
device, there is adopted a method of forming trenches and via holes
in an insulating film by etching, embedding metal layers in the
formed the trenches and the via holes and forming interconnect.
[0004] Shapes of the trenches and the via holes (hereinafter
referred to as "trenches or the like") are conventionally
controlled based on an etching time, but the control based on an
etching time involves a problem that it is difficult to accurately
grasp the shapes of the trenches or the like. Japanese Patent
Laid-Open No. 2006-295171, for example, discloses a method to form
interconnect by via-first method.
[0005] Japanese Patent Laid-Open No. 2006-073701 discloses a
monitoring method of etching rate by optical microscope when a film
with mask is etched to expose an underlying another film.
[0006] Japanese Patent Laid-Open No. 2003-229414, Japanese Patent
Laid-Open No. 2002-93870, National Publication of International
Patent Application No. 2006-506812 and National Publication of
International Patent Application No. 2006-518942 disclose a method
of irradiating light onto trenches or the like and grasping shapes
of the trenches or the like from reflected light (e.g.,
scatterometry method, OCD (Optical Critical Dimension) measurement.
Scatterometry method(or OCD measurement) generally includes both
single wavelength-multi angle optical scattering method and
multi-wavelength-single angle optical scattering method one.
[0007] For example, Japanese Patent Laid-Open No. 2003-229414 and
Japanese Patent Laid-Open No. 2002-93870 disclose a method of
irradiating light onto an insulating film in which a trench or the
like is formed and detecting reflected light from the insulating
film. The shape of the trench is grasped based on intensity of this
reflected light.
[0008] According to this method, an interconnect layer is disposed
below the trench to be measured. The shape of the trench is
measured using light of a wavelength-band in which the utilized
wavelength is larger than twice the wiring space of the
interconnect layer below the trench to be measured. This inhibits
the light from passing through the interconnect layer and prevents
the unfavorable reflection from the materials and/or features
underlying the interconnect layer.
[0009] For example, the interconnect layer is composed of a striped
tungsten metal film having a width of 175 nm, thickness of 250 nm
and a pitch of 350 nm, and the wiring space is assumed to be 175
nm. The wavelength-band of light used for measurement is assumed to
be 900 nm to 1600 nm.
[0010] However, the present inventor found out that the measuring
methods disclosed in the related arts have the following
problems.
[0011] When forming an interconnect layer, a trench is formed in an
insulating film, this trench is filled with a metal film, the metal
film is then polished and removed by CMP (Chemical Mechanical
polishing). In this case, erosion occurs as shown in FIG. 6.
[0012] In FIG. 6, reference numeral 901 denotes an insulating film,
902 denotes a metal film, 903 denotes an etching stopper film, 904
denotes an interlayer insulating film and 905 denotes a cap
film.
[0013] As shown in FIG. 6, steps are produced on the surface of the
cap film 905 at the top of the interconnect layer and the surface
undulates due to the influence of erosion.
[0014] When a trench is formed in such a condition, as shown in
FIGS. 7A and 7B, the shape of the trench 906 varies a great deal
due to a difference in positions at which the opening of a mask is
formed. Therefore, it is difficult to fix the measuring condition
of the trench 906 to a certain condition, which affects
productivity.
[0015] Furthermore, since the steps are produced on the surface of
the cap film 905 due to the influence of erosion, the steps remain
on the surface of the cap film 905 even after the trench 906 is
formed. In this case, the measuring light is reflected by the steps
and erroneous information is likely to occur when the trench 906 is
measured.
SUMMARY
[0016] The present invention provides a semiconductor device
comprising, a first insulating film on a semiconductor substrate
having a first region and a second region, a light shielding film
formed in the first region and an interconnect film formed in the
second region in the first insulating film and a second insulating
film having a first concave portion above the light shielding film
in the first region and an interconnect hole having a via hole and
a second concave portion in the second region in the second
insulating film on the first insulating film, wherein an area of
the light shielding film is overlapping an area of the first
plurality of concave portions.
[0017] According to the present invention, the area of the light
shielding film is overlapping the area of the first plurality of
concave portions, and therefore when the light shielding film is
polished CMP, it is possible to inhibit erosion from occurring in
the first insulating film.
[0018] Erosion is generally a phenomenon that occurs when the
interconnect pitch is narrow and densely arranged, and erosion
occurs conspicuously when the interconnect width is 1.6 .mu.m or
less.
[0019] On the contrary, as in the case of the present invention,
the area of the light shielding film is overlapping the area of the
first plurality of concave portions and when the distance from the
center to the outer perimeter of the light shielding film is
assumed to be 2 .mu.m or more and the light shielding film having a
large plane shape is formed, it is possible to reliably prevent
erosion from occurring.
[0020] In this way, even when an error occurs in the position at
which the opening of a mask is formed when a concave portion is
formed, it is possible to suppress variations in the shape of the
concave portion formed in the second insulating film. Therefore, it
is possible to conduct measurement by determining a measuring
condition to a certain condition and improve productivity of the
semiconductor device.
[0021] Furthermore, since the occurrence of erosion is prevented,
it is possible to inhibit steps from being formed on the surface of
the insulating film as in the cases of the related arts and prevent
measuring light from being reflected by the steps, producing
measurement errors when measuring the concave portion.
[0022] Furthermore, since the distance from the center to the outer
perimeter of the light shielding film in a plan view is assumed to
be 2 .mu.m or more, it is possible to effectively intercept
information of layers underlying the light shielding film when
irradiating light, detecting reflected light and measuring the
shape of the concave portion.
[0023] Furthermore, the present invention can also provide a method
for manufacturing a semiconductor device as follows.
[0024] That is, the present invention can provide a method of
manufacturing a semiconductor device comprising, forming a first
insulating film on a semiconductor substrate having a first region
and a second region, forming a first via hole in the second region
in the first insulating film, forming a reservoir region in the
first region and a trench in the second region to connect with the
first via to form a first interconnect hole in the first insulating
film, forming a metal film on the first insulating film to fill the
reservoir region and the first interconnect hole, performing
polishing so as to leave the metal film in the reservoir region to
form light shielding film and in the first interconnect hole to
form interconnect, forming a second insulating film on the first
insulating film, forming a second via hole in the second region in
the second insulating film, forming a first plurality of concave
portions above the light shielding film in the first region and a
second concave portion in the second region to connect with the
second via to form a second interconnect hole in the second
insulating film, wherein an area of the light shielding film is
overlapping an area of the first plurality of concave portions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The above and other objects, advantages and features of the
present invention will be more apparent from the following
description taken in conjunction with the accompanying drawings, in
which:
[0026] FIG. 1 is a cross-sectional view showing a semiconductor
device according to a first embodiment of the present
invention;
[0027] FIGS. 2A and 2B are cross-sectional views showing
manufacturing steps of a semiconductor device;
[0028] FIGS. 3A and 3B are cross-sectional views showing
manufacturing steps of a semiconductor device;
[0029] FIG. 4 is a plan view showing a relationship between a spot
size of measuring light, grooves and light shielding film;
[0030] FIGS. 5A and 5B show a semiconductor device according to a
second embodiment of the present invention;
[0031] FIG. 6 shows a related art of a semiconductor device;
and
[0032] FIGS. 7A and 7B show a related art of a semiconductor
device.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] The invention will be now described herein with reference to
illustrative embodiments. Those skilled in the art will recognize
that many alternative embodiments can be accomplished using the
teachings of the present invention and that the invention is not
limited to the embodiments illustrated for explanatory
purposes.
[0034] With reference now to the attached drawings, embodiments of
the present invention will be explained below.
First Embodiment
[0035] A first embodiment of the present invention will be
explained with reference to FIGS. 1 to 4.
[0036] First, an overview of a semiconductor device 1 of the
present embodiment will be explained.
[0037] As shown in FIG. 1, the semiconductor device 1 has a
flat-film-shaped first light shielding film 12 formed in a first
insulating film 11 and a second insulating film 13 provided on the
first light shielding film 12 in which a plurality of concave
portions 131 are formed. The plurality of concave portions 131 of
the second insulating film 13 is located above the first light
shielding film 12. The preferable area of the light shielding film
12 is an area of the circle of 2 .mu.m or more in the radius.
[0038] Next, the semiconductor device 1 will be explained in
detail.
[0039] The semiconductor device 1 is formed like a wafer in which a
plurality of circuit regions is formed and a scribe region is
formed between the circuit regions.
[0040] In addition to the above described first insulating film 11,
first light shielding film 12 and second insulating film 13, the
semiconductor device 1 has a second light shielding film 14, a
third insulating film 15, a third light shielding film 16, a fourth
insulating film, and further a semiconductor substrate 100 on which
the first insulating film 11 to the fourth insulating film 17 are
multilayered.
[0041] Here, the semiconductor device in which only four insulating
films are multilayered is disclosed, but the multilayer structure
of the semiconductor device is not limited to this.
[0042] The first insulating film 11 is formed on a semiconductor
substrate 100, for example, a silicon substrate such as a SiO2
film. The semiconductor substrate may be provided with
semiconductor elements such as the transistor 10 having the gate
structure and the diffusion region in the insulator layer 110 as
indicated in FIG. 1.
[0043] The first insulating film 11 is formed extending over the
circuit region to the scribe region. At the location of the scribe
region of this first insulating film 11, a reservoir region (first
reservoir region) 111 is formed.
[0044] This reservoir region 111 has a distance from the center to
the outer perimeter of 2 .mu.m or more when seen from the substrate
surface. The reservoir region 111 according to the present
embodiment has a plane rectangular shape, and one side has, for
example, 5 .mu.m or more. Above all, one side preferably has 30
.mu.m or more. Furthermore, one side more preferably has 80 .mu.m
or less.
[0045] The first light shielding film 12 is embedded in this
reservoir region 111.
[0046] In a plan view seen from the substrate side, the distance
from the center (center of gravity) to the outer perimeter of the
first light shielding film 12 is 2 .mu.m or more. More
specifically, the first light shielding film 12 is formed according
to the shape of the reservoir region 111 and has a plane
rectangular shape when seen from the substrate side. One side of
the first light shielding film 12 is 5 .mu.m or more. Above all,
the size of the first light shielding film 12 in the plan view seen
from the substrate side is preferably equal to or greater than the
light spot size of measuring light which will be described later,
and more specifically, the distance from the center to the outer
perimeter is preferably 15 .mu.m or more. Furthermore, in the plan
view seen from the substrate side, the distance from the center to
the outer perimeter of the first light shielding film 12 is
preferably 40 .mu.m or less.
[0047] According to the present embodiment, more specifically, the
first light shielding film 12 has a plane square shape and a length
L2 of one side is 60 .mu.m as shown in FIG. 4. Though details will
be described later, when the shape of the groove 131 is measured,
an alignment error between a stage on which the semiconductor
device is set and an irradiation section which irradiates measuring
light is taken into consideration, the length L2 is set to be equal
to or greater than the sum of the spot size of measuring light and
the alignment error.
[0048] Furthermore, the thickness of the first light shielding film
12 is, for example, 0.1 .mu.m to 1.2 .mu.m.
[0049] This first light shielding film 12 is made of metal, copper
or a copper alloy in the present embodiment.
[0050] The second insulating film 13 is provided on the first
insulating film 11 and is configured by including a low dielectric
constant film having a dielectric constant of, for example, 3.5 or
less. The second insulating film 13 is a multilayer film in which,
for example, a SiCN film 130A, SiOC film 130B and SiO2 film 130C
are multilayered in that order.
[0051] The second insulating film 13 as well as the first
insulating film 11 is formed extending over the circuit region to
the scribe region. A reservoir region (second reservoir region) 132
and the plurality of grooves 131 (first concave portion) are formed
in the part located in the scribe region of this second insulating
film 13. The reservoir region 132 is formed at a predetermined
distance from the plurality of grooves 131.
[0052] The reservoir region 132 and grooves 131 penetrate the SiO2
film 130C of the second insulating film 13 and reach a midway
position of the thickness of the SiOC film 130B.
[0053] Furthermore, a plurality of trenches 133 having the same
shape as the groove 131 are formed in the circuit region of the
second insulating film 13. The array pattern of the trenches 133 is
the same as the array pattern of the grooves 131 and the width,
length and height of the trench 133 are all the same as those of
the groove 131. The trench 135 is a trench for an interconnect
having a different width.
[0054] The groove 131 is slit-shaped and has, for example, a width
(size in the horizontal direction in FIG. 4) of 140 nm, array pitch
of 140 nm, length of L1 (size in the vertical direction in FIG. 4)
of 50 .mu.m and height (depth) of 350 nm.
[0055] The plurality of grooves 131 are arranged equidistantly and
regularly and extend parallel to each other. Since the groove 131
and the trench 133 have the same shape, the shape of the trench 133
can be grasped by grasping the shape of the groove 131. Therefore,
the plurality of grooves 131 can be said to be a mark for measuring
the trenches.
[0056] The measuring mark formed of these plurality of grooves 131
preferably has a diameter equal to or greater than the size of a
spot S of measuring light as shown in FIG. 4. For example, when the
spot size (diameter) of the measuring light is 30 .mu.m, the
distance from the plane center of the measuring mark to the outer
perimeter of the measuring mark is preferably 15 .mu.m or more. By
so doing, measurement can be performed reliably.
[0057] In the present embodiment, the spot size of the measuring
light is 30 .mu.m and the length L1 of one side of the measuring
mark formed of the plurality of grooves 131 (length in the array
direction of the grooves 131 and distance from the groove 131 on
one side to the groove 131 on the other side along the array
direction) is 50 .mu.m.
[0058] The plurality of grooves 131 are all located above the light
shielding film 12 in the aforementioned reservoir region 111, and
are arranged without sticking out of the light shielding film 12 in
a plan view seen from the substrate surface side as shown in FIG.
4. Only one light shielding film 12 is provided for the plurality
of grooves 131, that is, one measuring mark.
[0059] As shown in FIG. 1, the grooves 131 are filled with a metal
film 14A. This metal film 14A is similar to an interconnect film
14B with which the trenches 133 and 135 are filled and also the
light shielding film 14, which will be described later, and are
made of, for example, copper or a copper alloy.
[0060] The metal film 14A in the grooves 131 is insulated from the
light shielding film 12 by the SiOC film 130B and SiCN film 130A of
the second insulating film 13.
[0061] The reservoir region 132 has the same plane shape and size
as those of the trench region 111. The height of the reservoir
region 132 is greater than that of the reservoir region 111.
[0062] The light shielding film (second light shielding film) 14 is
disposed in this reservoir region 132. The plane size and shape of
this light shielding film 14 is the same as those of the light
shielding film 12. Furthermore, the material of the light shielding
film 14 is also the same as that of the light shielding film
12.
[0063] The third insulating film 15 is formed on the second
insulating film 13.
[0064] This third insulating film 15 has the same layer
configuration as that of the second insulating film 13 and is a
multilayer film where, for example, a SiCN film 150A, a SiOC film
150B and a SiO2 film 150C are multilayered in that order.
[0065] The third insulating film 15 is also formed extending over
the circuit region to the scribe region as in the case of the first
insulating film 11 or the like. A reservoir region (third reservoir
region) 152 and a plurality of grooves 151 (second concave portion)
are formed in the part located in the scribe region of this third
insulating film 15. The reservoir region 152 is formed at a
predetermined distance from the plurality of grooves 151.
[0066] The reservoir region 152 and grooves 151 penetrate the SiO2
film 150C of the third insulating film 15 and reaches a midway
position in the thickness of the SiOC film 150B.
[0067] Furthermore, a plurality of trenches 153 are formed in the
circuit region of the third insulating film 15 as in the case of
the grooves 151. The array pattern of the trenches 153 is the same
as the array pattern of the grooves 151 and the width, length and
height of the trench 153 are all the same as those of the groove
151. The trench 155 is a trench for an interconnect having a
different width.
[0068] The groove 151 is formed in a slit shape and has, for
example, a width of 140 nm, array pitch of 140 nm, length of 50
.mu.m and height of 350 nm.
[0069] The plurality of grooves 151 are all located above the light
shielding film 14 in the aforementioned reservoir region 132 and
arranged without sticking out of the light shielding film 14 in a
plan view seen from the substrate surface side.
[0070] The groove 151 is filled with a metal film 15A. This metal
film 15A is similar to an interconnect film 15B with which the
trenches 153 and 155 are filled and are made of, for example,
copper or a copper alloy.
[0071] The metal film 15A in the grooves 151 is insulated from the
light shielding film 14 by the SiOC film 150B and the SiCN film
150A of the third insulating film 15.
[0072] The reservoir region 152 has the same size and shape as
those of the reservoir region 132.
[0073] The light shielding film (third light shielding film) 16 is
disposed in this reservoir region 152. The size and shape in a plan
view of this light shielding film 16 are the same as those of the
light shielding film 12. The material of the light shielding film
16 is also the same as that of the light shielding film 12. The
fourth insulating film 17 is provided on the third insulating film
15.
[0074] This fourth insulating film 17 has the same layer
configuration as that of the second insulating film 13 and is a
multilayer film in which, for example, a SiCN film 170A, a SiOC
film 170B and a SiO2 film 170C are multilayered in that order.
[0075] As in the case of the first insulating film 11 or the like,
the fourth insulating film 17 is also formed extending over the
circuit region to the scribe region. A plurality of grooves (third
concave portion) 171 are formed in the part located in the scribe
region of this fourth insulating film 17.
[0076] The grooves 171 penetrate the SiO2 film 170C of the fourth
insulating film 17 and reach a midway position in the thickness of
the SiOC film 170B.
[0077] Furthermore, trenches 173 having the same shape as that of
the grooves 171 are formed in the circuit region of the fourth
insulating film 17. The array pattern of the trenches 173 is the
same as the array pattern of the grooves 171 and the width, length
and height of the trenches 173 are all the same as those of the
grooves 171.
[0078] The trench 175 is a trench for an interconnect having a
different width.
[0079] The groove 171 is slit-shaped and has, for example, a width
of 140 nm, array pitch of 140 nm, length of 50 .mu.m and height of
350 nm.
[0080] The plurality of grooves 171 are all located above the light
shielding film 16 in the aforementioned reservoir region 152 and
located without sticking out of the light shielding film 16 in a
plan view seen from the substrate surface side.
[0081] This groove 171 is filled with a metal film 17A. This metal
film 17A is similar to that of an interconnect film 17B with which
the trenches 173 and 175 are filled and are made of, for example,
copper or a copper alloy.
[0082] The metal film 17A in the groove 171 is insulated from the
light shielding film 16 by the SiOC film 170B and SiCN film 170A of
the fourth insulating film 17.
[0083] In the above described semiconductor device, the plurality
of grooves 131 are disposed above the light shielding film 12, the
light shielding film 16 is disposed above the plurality of grooves
131 and the grooves 171 are disposed above the light shielding film
16.
[0084] On the other hand, the grooves 151 are formed above the
light shielding film 14.
[0085] Next, the method of manufacturing the semiconductor device 1
will be explained with reference to FIGS. 2 and 3.
[0086] First, the transistor 10 having a gate structure and a
diffusion region and an insulating layer 110 and the insulating
film 11 are formed on the semiconductor substrate 100.
[0087] Next, the insulating film 11 is selectively removed by
etching and the reservoir region 111 is formed. The reservoir
region 111 is then filled and a metal film (light shielding layer)
is formed so as to cover the surface of the insulating film 11. The
metal film is then polished by CMP and only the metal film is left
in the reservoir region 111. In this way, the light shielding film
12 is formed (FIG. 2A). In the same time, an interconnect 121 is
formed.
[0088] Next, the insulating film 13 is provided on the insulating
film 11. Continually, insulating film 13 is etched to form a via
hole 134 with a mask in the circuit region. Because the insulator
film 130A is not etched when the via hole is formed, it may be done
to measure the shape of the via hole as described in the second
embodiment.
[0089] Further, the mask to form the trench connecting with the via
hole 134, the reservoir region 132 and grooves 131 is formed on the
insulating film 13. The insulating film 13 is then selectively
removed by etching, the reservoir region 132 and grooves 131 are
formed in the scribe region of the insulating film 13 and the
interconnect hole 136 having a trench 133 and a via hole 134 is
formed in the circuit region (FIG. 2B).
[0090] Next, the plurality of grooves 131 are irradiated with
light, reflected light is detected and the shape of the grooves 131
is acquired from the detected reflected light.
[0091] Here, examples of the method of acquiring the shape of the
grooves 131 from the reflected light include a scatterometry method
(light scattering measuring method). According to this method, a
database is created beforehand which associates the shape of the
grooves (e.g., depth (height) of the grooves, width of the grooves,
angle of the side wall with respect to the bottom surface of the
grooves or the like) with the waveform of reflected light. Light is
irradiated onto the grooves 131 and the waveform of the reflected
light is compared with the waveform in the database. When the
waveform of the reflected light matches the waveform in the
database, the shape of the grooves associated with the waveform in
the database is understood as an optimal value of the actual shape
of the grooves.
[0092] Since the plurality of grooves 131 have a size and shape
similar to those of the trenches 133 formed in the circuit region
and also have a similar array pattern, when the grooves 131 have a
desired shape, it is possible to judge that the trenches 133 formed
in the circuit region have a desired shape.
[0093] On the other hand, when the grooves 131 do not have the
desired shape, the trenches 133 in the circuit region are also
estimated not to have a desired shape. Semiconductor devices in
which the trenches 133 in the circuit region do not have the
desired shape are excluded so as not to move to the next step.
[0094] Furthermore, the difference between the shape of the grooves
131 and the desired shape is acquired and etching conditions such
as an etching time are adjusted. In this way, a desired shape is
obtained when trenches 133 in the next semiconductor device are
formed.
[0095] Next, the reservoir region 132, grooves 131 and the
interconnect hole 136 having a trench 133 and a via hole 134 are
filled and a metal film (light shielding layer) for covering the
surface of the insulating film 13 is formed. Then, after polishing
by CMP, this metal film remains in the reservoir region 132,
grooves 131 and the interconnect hole 136 having a trench 133 and a
via hole 134. In this way, the light shielding film 14, metal film
14A and interconnect 14B in the grooves 131 are formed.
[0096] Next, as shown in FIG. 3A, the insulating film 15 is
provided on the insulating film 13. Continually, insulating film 15
is etched to form a via hole 154 with a mask in the circuit region.
Because the insulator film 150A is not etched when the via hole is
formed, it may be done to measure the shape of the via hole as
described in the second embodiment.
[0097] Further, the mask to form the trench connecting with the via
hole 154, the reservoir region 152 and grooves 151 is formed on the
insulating film 13. After that, the insulating film 15 is
selectively removed by etching and reservoir region 152 and grooves
151 are formed in the scribe region of the insulating film 15 and
the interconnect hole 156 having a trench 153 and a via hole 154 is
formed in the circuit region.
[0098] The shape of the groove 151 is acquired using the same
method as that for acquiring the shape of the groove 131 and it is
judged whether or not the trenches 153 have a desired shape. When
the trenches 153 do not have the desired shape, this semiconductor
device is excluded so as not to move to the next step.
[0099] Furthermore, the difference between the shape of the groove
151 and the desired shape is acquired and etching conditions such
as an etching time are adjusted. When the trenches 153 are formed
in the next semiconductor device, this allows the trenches 153 to
have the desired shape.
[0100] Next, the metal film (light shielding layer) is formed to
fill the reservoir region 152, grooves 151 and trenches 153 and
cover the surface of the insulating film 15. Then, after polishing
by CMP, this metal film remains in the reservoir region 152,
grooves 151 and the interconnect hole 156 having a trench 153 and a
via hole 154. In this way, the light shielding film 16, the metal
film 15A in the grooves 151 and interconnect 15B are formed.
[0101] Next, as shown in FIG. 3B, the insulating film 17 is
provided on the insulating film 15.
[0102] After the masks to form a via hole 174 and a trench are
formed on the insulating film 17, as described above, the
insulating film 17 is then selectively removed by etching and the
grooves 171 are formed in the scribe region of the insulating film
17 and the interconnect hole 176 having a trench 173 and a via hole
174 are formed in the circuit region. It may be done to measure the
shape of the via hole 174 as described in the second
embodiment.
[0103] The shape of the groove 171 is acquired using the same
method as for acquiring the shape of the grooves 131 and it is
judged whether or not the trenches 173 have the desired shape. When
the trenches 173 do not have the desired shape, this semiconductor
device is excluded so as not to move to the next step.
[0104] Furthermore, the difference between the shape of the groove
171 and the desired shape is acquired and etching conditions such
as an etching time are adjusted. When the trenches 173 are formed
in the next semiconductor device, this allows the trenches 173 to
have the desired shape.
[0105] Next, the metal film (light shielding layer) is formed so as
to fill the grooves 171 and the interconnect hole 176 having a
trench 173 and a via hole 174, and cover the surface of the
insulating film 17. Then, after polishing by CMP, this metal film
remains in the grooves 171 and the interconnect hole 176 having a
trench 173 and a via hole 174. In this way, the metal film 17A in
the grooves 171 and the interconnect film 17B in the interconnect
hole 176 having a trench 173 and a via hole 174 are formed.
[0106] The semiconductor device 1 is completed in the above
described steps.
[0107] Next, the operations and effects of the present embodiment
will be explained.
[0108] According to the present embodiment, since the distance from
the center to the outer perimeter in a plan view of the light
shielding films 12, 14 and 16 is assumed to be 2 .mu.m or more, it
is possible to suppress the occurrence of erosion in the insulating
films 11, 13 and 15 when the light shielding films 12, 14 and 16
are formed by polishing by CMP. Especially, the light shielding
films 12, 14 and 16 are singly arranged only one each and the
respective light shielding films are not arranged in the plural,
and it is thereby possible to reliably suppress the occurrence of
erosion.
[0109] Therefore, even if there is an alignment error in the
arrangement of the openings of masks to form the grooves 131, 151
and 171, variations in the shapes of the grooves 131, 151 and 171
are suppressed. Therefore, measurement can be conducted with the
measuring conditions set to certain conditions and productivity can
be improved.
[0110] Furthermore, since the occurrence of erosion in the
insulating film 11 can be prevented, it is possible to prevent
steps from being formed due to the influence of erosion on the
surface of the insulating film 13 formed on the insulating film
11.
[0111] When the grooves 131 are measured, this can inhibit the
measuring light from being reflected by steps causing errors in the
measured value of the grooves 131.
[0112] Similar effects can also occur when the grooves 151 and 171
are formed.
[0113] Furthermore, the distance from the center to the outer
perimeter of the light shielding film 12 in the plan view is set to
2 .mu.m or more. When the groove pattern is irradiated with light,
the reflected light is detected and the shape of the grooves 131 is
measured, this can prevent the reflected light from layers
underlying the light shielding film 12 from mixing up. This allows
the shape of the grooves 131 to be accurately grasped.
[0114] Since the distance from the center to the outer perimeter of
the light shielding films 14 and 16 in the plan view is also set to
2 .mu.m or more, the shape of the grooves 151 and 171 can also be
grasped accurately as in the case of the grooves 131.
[0115] Furthermore, according to the present embodiment, the light
shielding film 12 has a size equal to or more than the spot size of
light irradiated onto the grooves 131. According to a scatterometry
method, since the spot size of light is generally 30 .mu.m, setting
the distance from the center to the outer perimeter of the light
shielding film 12 in a plan view to 30 .mu.m or more can prevent
light from passing below the light shielding film 12.
[0116] In this way, it is possible to prevent information on layers
underlying the light shielding film 12 from being included in the
reflected light from the grooves 131 and accurately grasp the shape
of the grooves 131.
[0117] Similar effects can also be obtained with the light
shielding films 14 and 16 because the light shielding films 14 and
16 are set to a size equal to or greater than the spot size of
light irradiated onto the grooves 151 and 171.
[0118] Furthermore, in the measuring device that measures grooves,
the present embodiment takes an alignment error between the stage
for setting the substrate on which the insulating films or the like
are multilayered and the irradiation section that irradiates
measuring light into consideration and sets the size of the light
shielding films 12, 14 and 16 in the plan view to a size equal to
or greater than the sum of the spot size of the measuring light and
the alignment error, and can thereby grasp the shapes of the
grooves 131, 151 and 171 more accurately.
[0119] On the other hand, the present embodiment sets upper limits
of the sizes of the light shielding films 12, 14 and 16 such that
the distance from the center to the outer perimeter of the light
shielding films 12, 14 and 16 is 40 .mu.m, and can thereby prevent
the scribe region from being narrowed by the light shielding films
12, 14 and 16.
[0120] Furthermore, the present embodiment forms the light
shielding films 12, 14 and 16 and grooves 131, 151 and 171 in the
scribe region, and can thereby prevent the circuit region from
being narrowed by the light shielding films 12, 14 and 16 and
grooves 131, 151 and 171.
[0121] Furthermore, the present embodiment arranges the plurality
of grooves 131 above the light shielding film 12, arranges the
light shielding film 16 above the plurality of grooves 131 and
arranges the grooves 171 above the light shielding film 16.
Furthermore, the present embodiment arranges the grooves 151 above
the light shielding film 14.
[0122] Adopting such a configuration minimizes the space in a plan
view in which the grooves and light shielding films are formed.
Various marks such as alignment marks may be formed in the scribe
region. When the light shielding films and grooves are formed in
the scribe region, it is possible to effectively use the scribe
region for a variety of applications without narrowing the scribe
region.
Second Embodiment
[0123] A second embodiment of the present invention will be
explained with reference to FIG. 5.
[0124] In the above described embodiment, gratings 131, 151 and 171
are formed, but in the present embodiment, a plurality of
cylindrical holes 231 are formed instead as shown in FIG. 5.
[0125] The plurality of holes 231 are formed in the scribe region
as in the case of the above described embodiment, and via holes
(not shown) having a size similar to that of the holes 231 are
formed in the circuit region of the insulating film 13. The array
pattern of the via holes is the same as the array pattern of the
holes 231.
[0126] Furthermore, as shown in FIG. 5B, the plurality of holes 231
are formed so as not to stick out of the light shielding film 12 in
a plan view.
[0127] The holes 231 are filled with a metal film 24A. This metal
film 24A is similar to the metal film 14A and is made of a material
similar to that for the vias with which the via holes are
filled.
[0128] The rest of aspects are the same as those of the above
described embodiment.
[0129] The present embodiment can exert effects similar to those in
the above described embodiment and can further exert the following
effects.
[0130] To acquire the shape of a via hole (e.g., size of the bottom
of the via hole), a length measuring SEM (Scanning Electron
microscope) is conventionally used. In contrast, use of a
scatterometry method as in the case of the present embodiment does
not take much time for measurement.
[0131] The present invention is not limited to the aforementioned
embodiments, but modifications, improvements or the like within the
scope in which the object of the present invention can be achieved
are included in the present invention.
[0132] For example, when measuring the shape of the grooves 131 or
the like, the above described embodiments compare the waveform of
reflected light from the grooves 131 with waveforms in the database
beforehand and determine the shape of the grooves from the matching
waveform in the database.
[0133] However, the method of measuring the shape of the grooves
131 or the like is not limited to such a method, but it is also
possible to grasp the shape of the grooves 131 or the like based on
the intensity of reflected light from the grooves 131 or the like
as in the case of Patent Document 1.
[0134] Furthermore, the above described embodiments form the
grooves 131 or the like and a light shielding film 12 or the like
in the scribe region, but the present invention is not limited to
this and these may also be formed in the circuit region.
[0135] Furthermore, the first embodiment assumes that the plurality
of grooves 131 are arranged above the light shielding film 12, the
light shielding film 16 is arranged above the plurality of grooves
131 and the grooves 171 are arranged above the light shielding film
16, but the present invention is not limited to such a structure.
That is, the light shielding film 16 may also be provided at a
location shifted from the location above the plurality of grooves
131.
[0136] Furthermore, the above described embodiments arrange the
plurality of grooves 131 so as not to stick out of the light
shielding film 12 in the plan view seen from the substrate surface
side, but the present invention is not limited to this and the
grooves 131 may also be arranged such that parts of the grooves
131, for example, an end in the longitudinal direction of the
grooves 131 sticks out of the light shielding film 12.
[0137] However, by arranging the plurality of grooves 131 so as not
to stick out of the light shielding film 12 as in the cases of the
above described embodiments, it is possible to reliably intercept
the information of layers underlying the light shielding film 12
when measuring the shape of the grooves 131.
EXAMPLES
[0138] Next, examples of the present invention will be
explained.
Example 1
[0139] As in the case of the first embodiment, the light shielding
film 12 was formed in the insulating film 11. The light shielding
film 12 was assumed to be a square of 4 .mu.m per side. CMP was
applied when the light shielding film 12 was formed, but no erosion
occurred.
[0140] Furthermore, the insulating film 13 was provided on the
light shielding film 12, but the surface of the insulating film 13
was flat and no projections and depressions were formed. The
plurality of grooves 131 and trenches 133 were then formed in the
insulating film 13.
[0141] The width (length in the short side direction) of the groove
131 and a trench 133 was 140 nm, the height was 370 nm and the
depth (length in the long side direction) of the groove 131 and a
trench 133 was 50 .mu.m.
[0142] The length L1 of one side of the square measuring mark made
up of the plurality of grooves 131 was 50 .mu.m.
[0143] No erosion occurs if the size of the light shielding film 12
is determined such that the distance from the center to the outer
perimeter is 2 .mu.m or more. Therefore, even when an error occurs
in the location where the opening of the mask is formed when the
plurality of grooves 131 and trenches 133 are formed, variations in
the shapes of the plurality of grooves 131 and trenches 133 are
suppressed. Furthermore, since no projections and depressions are
formed on the surface of the insulating film 13, it is
understandable that it is possible to suppress the reflection of
measuring light by steps and the occurrence of measurement
errors.
[0144] Furthermore, the grooves 131 were measured using a
scatterometry method. The spot size of measuring light was assumed
to be 30 .mu.m. The grooves 131 could be measured in Example 1.
Example 2
[0145] As in the case of the first embodiment, the light shielding
film 12 was formed in the insulating film 11. The light shielding
film 12 was assumed to be a square having the length L2 of 60 .mu.m
per side. The insulating film 13 was provided on the light
shielding film 12 and the plurality of grooves 131 and trenches 133
were formed in the insulating film 13.
[0146] The length L1 per side of the square measuring mark made up
of the plurality of grooves 131 was assumed to be 50 .mu.m. The
grooves 131 were measured using a scatterometry method. The spot
size of the measuring light was set to 30 .mu.m here.
[0147] Table 1 shows the depth of the bottom of the plurality of
groove 131 measured using the scatterometry method and the depth of
the plurality of grooves 131 measured using a cross-sectional SEM
as in the case of the first embodiment.
TABLE-US-00001 TABLE 1 Measured value (nm) using scatterometry
method Cross-sectional SEM value (nm) 378.6 377 376.5 377 388.4 390
378.1 380 396.2 394 388.9 387 377.3 380 380.7 377 390.3 390
This table shows that accurate measurement is made possible by
providing the light shielding film.
[0148] CMP was applied when the light shielding film was provided
but no erosion was found.
Example 3
[0149] In Example 3, the light shielding film 12 was formed in the
insulating film 11 as in the case of the second embodiment. The
light shielding film 12 was assumed to be a square having the
length L2 of 60 .mu.m per side. The insulating film 13 was provided
on the light shielding film 12 and a plurality of holes 231 and via
holes were formed in the insulating film 13.
[0150] The length L1 of one side of the square measuring mark made
up of the plurality of holes 231 (length from the hole 231 at an
end of one side of the square to the hole 231 at the other end) was
assumed to be 50 .mu.m.
[0151] The rest of aspects are the same as those in Example 2.
[0152] The widths of the bottom of 17 holes 231 in the plane of the
semiconductor substrate were measured using a scatterometry method.
Furthermore, the widths of the bottom of 17 holes 231 were measured
using a length measuring SEM.
[0153] Table 2 shows the results.
TABLE-US-00002 TABLE 2 Measured value (nm) using scatterometry
Cross-sectional method SEM value (nm) Mean value (nm) 115.8 115.8
3.sigma. (nm) 5.2 3.2 Max (nm) 118.0 117.6 Min (nm) 112.2 113.7
[0154] This table shows that accurate measurement is made possible
by providing the light shielding film.
[0155] CMP was applied when the light shielding film was provided,
but no erosion was found.
Comparative Example 1
[0156] An insulating film was provided on a semiconductor substrate
and trenches having a width of 175 nm, a height of 250 nm and a
pitch of 350 nm were formed in this insulating film. Next, a
tungsten metal film was formed so as to fill these trenches and
cover the insulating film and was then polished for
planarization.
[0157] In this case, erosion occurred in the insulating film and
projections and depressions were formed on the surface of the
insulating film.
[0158] Next, a second insulating film was provided on the
insulating film and trenches having a width of 175 nm, a height of
250 nm and a pitch of 350 nm were formed in the second insulating
film. Projections and depressions were formed on the surface of the
second insulating film due to an influence of erosion.
[0159] When the shape of the trenches was measured as in the case
of Example 2, a large difference between the measured value using a
SEM and the measured value using scatterometry method was observed
due to the projections and depressions on the surface of the second
insulating film.
* * * * *