U.S. patent application number 09/826038 was filed with the patent office on 2002-05-16 for method and system for manufacturing semiconductor device.
This patent application is currently assigned to MITSUBISHI DENKI KABUSHIKI KAISHA. Invention is credited to Ohmori, Toshiaki.
Application Number | 20020056700 09/826038 |
Document ID | / |
Family ID | 18822503 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020056700 |
Kind Code |
A1 |
Ohmori, Toshiaki |
May 16, 2002 |
Method and system for manufacturing semiconductor device
Abstract
The present invention aims at high-yield manufacture of a
semiconductor device of stable quality. A silicon oxide film, a
polysilicon film, and a silicon nitride film are formed on a
silicon substrate. After a predetermined trench structure has been
formed in the films by means of etching, an oxide film is deposited
so as to fill in the trench structure. The silicon substrate is
subjected to chemical-and-mechanical polishing (CMP) while the
silicon nitride film is used as a stopper film, thereby forming an
isolation oxide film. The thickness of the isolation oxide film is
measured, and the isolation oxide film is etched under the
requirements which have been determined on the basis of the
resultant measurement value, by means of the feedforward technique.
Subsequently, the silicon nitride film and the polysilicon film are
removed sequentially.
Inventors: |
Ohmori, Toshiaki; (Tokyo,
JP) |
Correspondence
Address: |
McDermott, Will & Emery
600 13th Street, N.W.
Washington
DC
20005-3096
US
|
Assignee: |
MITSUBISHI DENKI KABUSHIKI
KAISHA
|
Family ID: |
18822503 |
Appl. No.: |
09/826038 |
Filed: |
April 5, 2001 |
Current U.S.
Class: |
216/84 ; 216/99;
257/E21.244; 257/E21.525 |
Current CPC
Class: |
H01L 22/20 20130101;
H01L 2924/0002 20130101; H01L 21/31053 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
216/84 ;
216/99 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2000 |
JP |
2000-349027 |
Claims
What is claimed is:
1. A method of manufacturing a semiconductor device including a
plurality of processing processes, the method comprising: a first
step of acquiring a measurement value pertaining to a wafer to be
subjected to a predetermined processing process; a second step of
determining processing requirements for the predetermined
processing process on the basis of the measurement value; and a
third step of performing the predetermined processing process in
accordance with the processing requirements determined in the
second step.
2. The method of manufacturing a semiconductor device according to
claim 1, wherein the predetermined processing is etching of a
predetermined film to be processed, and the predetermined
measurement value is a value expressing a physical quantity of the
film to be processed.
3. The method of manufacturing a semiconductor device according to
claim 2, wherein the measurement value is the thickness of the film
to be processed.
4. The method of manufacturing a semiconductor device according to
claim 2, wherein the film to be processed is a silicon oxide film
including impurities, and the measurement value is the
concentration of impurities contained in the silicon oxide
film.
5. The method of manufacturing a semiconductor device according to
claim 2, wherein the measurement value is the refractive index of
the film to be processed.
6. The method of manufacturing a semiconductor device according to
claim 2, wherein the measurement value is the dimension of the film
to be processed.
7. The method of manufacturing a semiconductor device according to
claim 1, wherein the first step comprises a sub-step in which a
measurement apparatus disposed in a manufacturing line acquires the
predetermined measurement value; the second step includes a
sub-step in which the measurement apparatus transmits the
predetermined measurement value to a main computer disposed in the
manufacturing line, and a sub-step in which the main computer
determines the processing requirements on the basis of the
measurement value by reference to a processing recipe stored in the
main computer in advance; and the third step includes a sub-step in
which the main computer transmits the processing requirements
determined in the second step to a processing apparatus disposed in
the manufacturing line, and a sub-step in which the processing
apparatus performs the predetermined processing process in
accordance with the processing requirements.
8. The method of manufacturing a semiconductor device according to
claim 1, wherein the first step comprises a sub-step in which a
measurement apparatus disposed in a manufacturing line acquires the
predetermined measurement value; the second step includes a
sub-step in which the measurement apparatus transmits the
predetermined measurement value to a main computer disposed in the
manufacturing line, a sub-step in which the main computer transmits
an instruction signal determined on the basis of the measurement
value to a processing apparatus disposed in the manufacturing line,
and a sub-step in which the processing apparatus determines the
processing requirements on the basis of the measurement value by
reference to a processing recipe stored in the main computer in
advance; and the third step includes a sub-step in which the
processing apparatus performs the predetermined processing process
in accordance with the processing requirements determined in the
second step.
9. The method of manufacturing a semiconductor device according to
claim 1, wherein: the predetermined processing is wet etching of a
predetermined film to be processed; the predetermined measurement
value is a value expressing the physical quantity of the film to be
processed; the method further comprises a fourth step of counting a
time which has elapsed since replacement of a chemical to be used
for the wet etching; in the second step, wet-etching processing
requirements are determined on the basis of the measurement value
and the elapsed time; and, in the third step, wet etching of the
film is performed in accordance with the wet-etching processing
requirements.
10. A method of manufacturing a semiconductor device, comprising
the steps of: wet etching a predetermined film to be processed;
counting a time which has elapsed since replacement of a chemical
to be used for the wet etching; and determining processing
requirements for the wet etching on the basis of the elapsed time;
wherein said wet etching is performed in accordance with the
processing requirements.
11. A semiconductor device manufacturing system which performs a
plurality of processing processes, the system comprising: a
measurement apparatus for acquiring a predetermined measurement
value pertaining to a wafer to be subjected to a predetermined
processing process; a recipe determination section for determining
processing requirements for the predetermined processing process on
the basis of the measurement value; and a processing apparatus for
performing the predetermined processing process in accordance with
the processing requirements determined by the recipe determination
section.
12. The semiconductor device manufacturing system according to
claim 11, wherein the predetermined processing is etching of a
predetermined film to be processed, and the predetermined
measurement value is a value expressing a physical quantity of the
film to be processed.
13. The semiconductor device manufacturing system according to
claim 12, wherein the measurement value is the thickness of the
film to be processed.
14. The semiconductor device manufacturing system according to
claim 12, wherein the film to be processed is a silicon oxide film
including impurities, and the measurement value is the
concentration of impurities contained in the silicon oxide
film.
15. The semiconductor device manufacturing system according to
claim 12, wherein the measurement value is the refractive index of
the film to be processed.
16. The semiconductor device manufacturing system according to
claim 12, wherein the measurement value is the dimension of the
film to be processed.
17. The semiconductor device manufacturing system according to
claim 11, further comprising a main computer capable of
establishing communication with the measurement apparatus and the
processing apparatus; wherein the main computer comprises: the
recipe determination section; a measurement value receiving section
for receiving the measurement value transmitted from the
measurement apparatus; a recipe memory for storing a plurality of
processing recipes; and a recipe transmission section for
transmitting processing requirements determined by the recipe
determination section to the processing apparatus; and wherein the
recipe determination section determines the processing requirements
on the basis of the measurement value by reference to the
processing recipe stored in the recipe memory.
18. The semiconductor device manufacturing system according to
claim 11, further comprising a main computer capable of
establishing communication with the measurement apparatus and the
processing apparatus; wherein the main computer comprises: a
measurement value receiving section for receiving the measurement
value transmitted from the measurement apparatus; and an
instruction transmission section for transmitting to the processing
apparatus an instruction signal in accordance with the measurement
value; wherein the processing apparatus comprising: the recipe
determination section; and a recipe memory for storing a plurality
of processing recipes; wherein the recipe determination section
determines the processing requirements on the basis of the
instruction signal by reference to the processing recipe stored in
the recipe memory.
19. The semiconductor device manufacturing system according to
claim 11, wherein: the processing apparatus is a wet-etching
apparatus for subjecting to wet etching a predetermined film to be
processed; the measurement apparatus is an apparatus for measuring
a value representing a physical quantity of the film to be
processed; said manufacturing system further comprises an
elapsed-time management section for counting a time which has
elapsed since replacement of a chemical to be used for the wet
etching, and a recipe correction section for correcting
requirements for the wet etching in accordance with the elapsed
time; and the wet-etching apparatus performs the wet etching in
accordance with the processing requirements processed by the recipe
determination section and the recipe correction section.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method and system for
manufacturing a semiconductor device. More particularly, the
present invention relates to a manufacturing method and system
effective for increasing the yield of a semiconductor device.
[0003] 2. Description of the Background Art
[0004] There has hitherto been proposed a technique of stabilizing
processes by means of measuring the thickness of a film formed on a
wafer before and after etching, and feeding back a measurement
result to etching requirements. For instance, Japanese Patent
Application Laid-Open No. H10-275753 describes a technique of
measuring the thickness of a film at an arbitrary frequency after
formation or etching of a predetermined film, thus ascertaining
successive variations in a film-growth system and an etching system
on the basis of the result of measurement. In the related art
technique, information pertaining to the thus-ascertained
successive variations is utilized as basic data to be used for
determining the time at which an alarm is to be issued or the time
at which maintenance of the system is to be performed, or as basic
data to be used for adjusting film-growth requirements or etching
requirements. Japanese Patent Application Laid-Open No. H7-29958
describes a technique of performing predetermined inspection before
and after processing of a wafer, thereby automatically changing
wafer processing requirements on the basis of an inspection
result.
[0005] These related-art techniques are to feed back the result of
inspection of a wafer before and after predetermined processing to
requirements for the processing. In short, the related-art
techniques are to correct processing requirements for a certain
process, in accordance with the state of the wafer which has been
subjected to the process. In this case, the result of inspection of
a certain wafer is not reflected in the processing of the wafer. In
this respect, the related-art techniques encounter a problem of
processing errors of respective processes being accumulated in
respective wafers.
SUMMARY OF THE INVENTION
[0006] The present invention has been conceived to solve such a
problem and is aimed at providing a manufacturing method which
enables high-yield manufacture of a semiconductor device of stable
quality, by means of reflecting the state of a wafer in the
requirements for processing the wafer through use of the
feedforward technique.
[0007] The present invention is also aimed at providing a
manufacturing system which enables high-yield manufacture of a
semiconductor device of stable quality, by means of reflecting the
state of a wafer in requirements for processing the wafer through
use of the feedforward technique.
[0008] The above objects of the present invention are achieved by a
method of manufacturing a semiconductor device described below. The
method includes a first step of acquiring a measurement value
pertaining to a wafer to be subjected to a predetermined processing
process. The method also includes a second step of determining
processing requirements for the predetermined processing process on
the basis of the measurement value. The method further includes
third step of performing the predetermined processing process in
accordance with the processing requirements determined in the
second step.
[0009] The above objects of the present invention are achieved by a
method of manufacturing a semiconductor device described below. The
method includes a step of wet etching a predetermined film to be
processed. The method also includes a step of counting a time which
has elapsed since replacement of a chemical to be used for the wet
etching. The method further includes a step of determining
processing requirements for the wet etching on the basis of the
elapsed time. The wet etching is performed in accordance with the
processing requirements.
[0010] The above objects of the present invention are achieved by a
semiconductor device manufacturing system which performs a
plurality of processing processes. The system includes a
measurement apparatus for acquiring a predetermined measurement
value pertaining to a wafer to be subjected to a predetermined
processing process. The system also includes a recipe determination
section for determining processing requirements for the
predetermined processing process on the basis of the measurement
value. The system further includes a processing apparatus for
performing the predetermined processing process in accordance with
the processing requirements determined by the recipe determination
section.
[0011] Other objects and further features of the present invention
will be apparent from the following detailed description when read
in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a block diagram for describing a construction of a
system for manufacturing a semiconductor device according to a
first embodiment of the present invention;
[0013] FIG. 2A is a cross sectional view for describing a
manufacturing method according to the first embodiment of the
present invention;
[0014] FIG. 2B is a flowchart for describing a manufacturing method
according to the first embodiment of the present invention;
[0015] FIG. 3A is a cross sectional view for describing a
manufacturing method according to a second embodiment of the
present invention;
[0016] FIG. 3B is a flowchart for describing a manufacturing method
according to a second embodiment of the present invention;
[0017] FIG. 4A is a cross sectional view for describing a
manufacturing method according to a third embodiment of the present
invention;
[0018] FIG. 4B is a flowchart for describing a manufacturing method
according to a third embodiment of the present invention;
[0019] FIG. 5A is a cross sectional view for describing a
manufacturing method according to a forth embodiment of the present
invention;
[0020] FIG. 5B is a flowchart for describing a manufacturing method
according to a fourth embodiment of the present invention;
[0021] FIG. 6 is a graph showing a relationship between an etching
rate and an impurity concentration;
[0022] FIGS. 7A through 7D are cross sectional views for describing
a manufacturing method according to a fifth embodiment of the
present invention;
[0023] FIG. 7E is a flowchart for describing a manufacturing method
according to a fifth embodiment of the present invention; and
[0024] FIG. 8 is a block diagram for describing a construction of a
system for manufacturing a semiconductor device according to a
sixth embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] Embodiments of the present invention will be described by
reference to the accompanying drawings. Throughout the drawings,
like elements are assigned like reference numerals, and repetition
of their explanations is omitted.
[0026] First Embodiment
[0027] FIG. 1 is a block diagram showing the construction of a
system for manufacturing a semiconductor device according to a
first embodiment of the present invention. As shown in FIG. 1, the
manufacturing system according to the present embodiment comprises
a main computer 10, a measurement apparatus 12, and a processing
apparatus 14. The main computer 10, the measurement apparatus 12,
and the processing apparatus 14 are interconnected by way of a
communications channel so as to effect mutual communication of
information.
[0028] The processing apparatus 14 is to perform various processing
operations to be performed during the course of manufacture of a
semiconductor device. The processing apparatus 14 is constituted
of, for example, a film-growth machine for forming a predetermined
film on a wafer, and a dry or wet etching machine for etching the
film formed on the wafer. Although a plurality of pieces of
processing apparatus 14 are shown in FIG. 1, the manufacturing
system according to the present embodiment may comprise only one
processing apparatus 14.
[0029] The measurement apparatus 12 is to subject a wafer to a
predetermined inspection during the course of manufacture of a
semiconductor device. The measurement apparatus 12 is constituted
of, for example, a film thickness measurement machine for measuring
the thickness of a film formed on the surface of a wafer; an
impurity measurement machine for measuring the concentration of
impurities contained in the film formed on the surface of the
wafer; a size measurement machine for measuring the size of a
pattern formed on the surface of a wafer; or an interlayer oxide
film measurement machine for measuring an interlayer oxide film
formed on the surface of the wafer. Although FIG. 1 shows only one
measurement machine 12, a plurality of measurement machines 12 may
be provided within the manufacturing system according to the
present embodiment.
[0030] The main computer 10 is equipped with a measurement value
receiving section 16 for receiving a value measured by the
measurement apparatus 12. The measurement value received by the
measurement value receiving section 16 is stored into measurement
value memory 20 along with an ID assigned to a wafer which is an
object of measurement, by means of a measurement value memorizing
section 18.
[0031] The main computer 10 is also equipped with an ID receiving
section 22. Before starting processing of a wafer, the processing
apparatus 14 sends to the main computer 10 the ID assigned to a
wafer which is an object of processing. Hereinafter, the processing
apparatus 14 that has transmitted an ID will be referred to
specifically as an object-of-control processing apparatus 14. The
ID receiving section 22 receives the ID transmitted by the
object-of-control processing apparatus 14 and transfers the
thus-received ID to a recipe determination section. In accordance
with the ID, the recipe determination section 24 reads from the
measurement value memory 20 the measurement value pertaining to the
wafer to be processed by the object-of-control processing apparatus
14; more particularly, a measurement value measured immediately
before the object-of-control processing apparatus 14 performs
processing.
[0032] Requirements which are used by the object-of-control
processing apparatus 14 to process a wafer should be set
appropriately in accordance with the state of the wafer at a point
in time at which the processing is commenced. More specifically,
the requirements which are used by the object-of-control processing
apparatus 14 to process a wafer should be set appropriately in
accordance with a measured value pertaining to the wafer measured
immediately before the processing.
[0033] A recipe memory 26 provided to the main computer 10 stores
optimal processing requirements for the object-of-control
processing apparatus 14 that have been determined beforehand on the
basis of a relation with the above mentioned measured value. The
recipe determination section 24 described above reads out a
measured value from the measurement value memory 20 so as to reads
out optimal processing requirements from the recipe memory 26 based
on the measured value. The thus-read optimal processing
requirements are sent to the object-of-control processing apparatus
14 by means of a recipe transmission section 28.
[0034] The object-of-control processing apparatus 14 processes the
wafer according to the optimal requirements thus transmitted from
the main computer 10. As mentioned above, the manufacturing system
according to the present embodiment can reflect the state of the
wafer measured by the measurement apparatus 12 in the processing
requirements for the object-of-control processing apparatus 14, by
means of the feedforward technique. More specifically, the
manufacturing system according to the present embodiment can
reflect the state of a wafer measured by the measurement apparatus
12 in requirements used for processing the wafer itself. Therefore,
the manufacturing system according to the present embodiment
enables high-yield manufacture of a semiconductor device of stable
quality without errors of respective processes being accumulated in
a wafer.
[0035] The operation of the manufacturing system according to the
first embodiment of the present invention will be described in more
detail by reference to FIGS. 2A and 2B.
[0036] The manufacturing system according to the present embodiment
is aimed at accurately controlling a step difference between the
surface of an isolation oxide film to be embedded in a trench and
the surface of a silicon substrate, during the course of
manufacture of an element isolation structure through use of a
trench structure. During the course of manufacture of an element
isolation structure using a trench isolation structure, processing
described below is performed.
[0037] As shown in FIG. 2A, a silicon oxide film 35, a polysilicon
film 34, and a silicon nitride film 32 are formed on the surface of
a silicon substrate 31. The silicon nitride film 32 is patterned in
accordance with the geometry of a trench to be formed. The silicon
substrate 31 is subjected to dry etching while the thus-patterned
silicon nitride film 32 is used as a mask, whereby a trench
structure is formed in the silicon substrate 31. An oxide film is
deposited on the entire surface of the silicon substrate 31 such
that the trench structure is filled with the oxide film, by means
of chemical vapor deposition (CVD). Subsequently, the oxide film
overflowing the trench structure is removed by means of
chemical-and-mechanical polishing (CMP), to thereby remain the
oxide film within only the trench structure for forming an
isolation oxide film 33.
[0038] In the present embodiment, CMP is followed by etching of the
isolation oxide film 33, etching of the silicon nitride film 32,
and etching of the polysilicon film 34, in the sequence given.
During the course of the previously-described round of processing,
comparatively large errors are likely to arise in the abrasion
amount to be attained in the course of CMP. For this reason, if
etching of the isolation oxide film 33 is performed in accordance
with default requirements, difficult is encountered in accurately
forming a step difference between the surface of the isolation
oxide film 33 and the surface of the silicon substrate 31 such that
the step assumes a desired final value.
[0039] As shown in FIG. 2B, in the present embodiment, after CMP
processing of the oxide film has been completed, the thickness of
the isolation oxide film 33 is measured. The resultant measurement
value is reflected in the requirements for etching the isolation
oxide film 33, by means of the feedforward technique. In the
present embodiment, a film thickness measurement apparatus used for
measuring the thickness of the isolation oxide film 33 after CMP
corresponds to the measurement apparatus 12 shown in FIG. 1.
Further, an etching machine used for etching the isolation oxide
film 33 corresponds to the object-of-control processing apparatus
14.
[0040] Every time CMP of a wafer is completed, the manufacturing
system according to the embodiment measures the thickness of the
isolation oxide film 33 formed on the wafer. The resultant
measurement value is transmitted to the main computer 10, and the
thus-transmitted measurement value is recorded in the measurement
value memory 20 along with the ID assigned to the wafer. Further,
when the wafer has reached a process of etching the isolation oxide
film 33, the etching machine requests the main computer 10 to
transmit optimal requirements. Thus, processing requirements for
the etching machine are set to the optimal requirements determined
by the recipe determination section 24. Subsequently, the isolation
oxide film 33 is etched according to the optimal requirements.
[0041] The manufacturing method according to the present embodiment
enables a step difference between the surface of the isolation
oxide film 33 and the surface of the silicon substrate 31 to be
accurately controlled to a desired value at all times finally,
regardless of variations in the amount of abrasion attained in the
course of CMP. Accordingly, the manufacturing method and system
according to the present embodiment enable high-yield manufacture
of a semiconductor device of stable quality.
[0042] In the first embodiment, an ID is set on a per-wafer basis,
and requirements for etching the isolation oxide film 33 are set on
a per-wafer basis. The present invention is not limited to this
embodiment. Specifically, an ID may be set on a per-lot basis, and
etching requirements may be set on a per-lot basis.
[0043] In the first embodiment, processing requirements are set
within the main computer 10, and the requirements are sent from the
main computer 10 to the etching apparatus (the object-of-control
apparatus 14). The present invention is not limited to this
embodiment. Specifically, a plurality of processing requirements
may be stored beforehand in the etching machine, and the main
computer 10 may select optimal requirements from the
requirements.
[0044] Second Embodiment
[0045] A second embodiment of the present invention will now be
described by reference to FIGS. 3A and 3B.
[0046] Under the manufacturing method according to the present
embodiment, after a wafer has been subjected to CMP in accordance
with the same procedures as those employed in the first embodiment,
the silicon nitride film 32 is etched, as shown in FIG. 3B. FIG. 3A
shows the wafer in which the silicon nitride film 32 has been
removed from the polysilicon film 34.
[0047] After etching of the silicon nitride film 32, the
measurement apparatus 12 measures the thickness of the isolation
oxide film 33. The thus-measured thickness value is transmitted to
the main computer 10 in the same manner as in the first embodiment,
and the value is recorded along with an ID assigned to the
wafer.
[0048] The isolation oxide film 33 is etched from the wafer. At
this time, processing requirements for the etching machine
(corresponding to the object-of -control processing apparatus 14)
are set to optimal requirements by the main computer 10, as in the
case of the first embodiment.
[0049] By means of the manufacturing method and system according to
the present embodiment, variations in the thickness of the
isolation oxide film 33 stemming from CMP and variations in the
thickness of the isolation oxide film stemming from removal of the
silicon nitride film 32 can be reflected in the requirements for
etching the isolation oxide film 33. The manufacturing method and
system according to the present embodiment enable more accurate
control of the step between the surface of the isolation oxide film
33 and the surface of the silicon substrate 31 to a desired value
than that attained in the first embodiment.
[0050] Third Embodiment
[0051] A third embodiment of the present invention will now be
described by reference to FIGS. 4A and 4B.
[0052] The third embodiment is aimed at accurately controlling the
thickness of an interlayer oxide film during an etching process
intended for smoothing the interlayer oxide film of a semiconductor
device. In the present embodiment, processing is effected in the
following manner during the course of manufacture of a
semiconductor device.
[0053] As shown in FIG. 4A, various interconnection elements such
as a gate electrode 38 of a transistor and a capacitor electrode 40
of a memory cell are formed on the silicon substrate 31. An
interconnection oxide film 42 is deposited on the entire surface of
the silicon substrate 31 so as to cover all the interconnection
elements, by means of, for example, the CVD technique. At this
time, on the surface of the interlayer oxide film 42 there are
formed steps difference ascribable to presence/absence of the
interconnection elements and structural dissimilarities between the
interconnection elements.
[0054] In a subsequent process, an unillustrated upper
interconnection is formed on the interlayer oxide film 42. The step
differences formed on the surface of the interlayer oxide film 42
would induce patterning failures at the time of formation of an
upper interconnection. For this reason, in the present embodiment,
a resist film 44 is formed so as to cover recessed areas of the
interlayer oxide film 42, then the interlayer oxide film 42 is
etched back while the resist film 44 is taken as a mask, before
formation of an upper interconnection.
[0055] As shown in FIG. 4B, in the present embodiment, after the
interlayer oxide film 42 has been deposited, the thickness of the
interlayer oxide film 42 is measured before a resist film 44 is
formed by means of photolithography. The resultantly-measured value
is reflected in the requirements for etching back the interlayer
oxide film 42, by means of the feedforward technique. In the
present embodiment, a film thickness measurement apparatus for
measuring the thickness of the interlayer oxide film 42 after
deposition thereof corresponds to the measurement apparatus 12
shown in FIG. 1. Further, an etching machine used for etching back
the interlayer oxide film 42 corresponds to the object-of-control
processing apparatus 14.
[0056] By means of the manufacturing system according to the
present embodiment, a film thickness measurement apparatus
(corresponding to the measurement apparatus 12) measures the
thickness of the interlayer oxide film 42 immediately after
deposition thereof on a wafer. The resultantly-measured value is
transmitted to the main computer 10, and the value is recorded in
the measurement value memory 20 along with an ID assigned to the
thus-measured wafer. When the wafer has reached a process of
etching back the interlayer oxide film 42, the etching machine
(corresponding to the object-of-control apparatus 14) requests the
main computer 10 to transmit optimal requirements. The recipe
determination section 24 of the main computer 10 sets as processing
requirements for the etching machine the optimal requirements,
which are determined on the basis of the thickness of the
interlayer oxide film 42.
[0057] According to the manufacturing method, the thickness of the
interlayer oxide film 42 can be made uniform to high accuracy
before formation of an upper interconnection. The manufacturing
method and system according to the present embodiment enable
effective prevention of patterning failures in an upper
interconnection and high-yield manufacture of a semiconductor
device of stable quality.
[0058] In the third embodiment, an ID is set on a per-wafer basis,
and requirements for etching the interlayer oxide film 42 are also
set on a per-wafer basis. However, the present invention is not
limited to this embodiment. Specifically, an ID may be set on a
per-lot basis, and etching requirements may be set on a per-lot
basis.
[0059] In the third embodiment, processing requirements are set
within the main computer 10, and the thus-set processing
requirements are transmitted from the main computer 10 to the
etching machine (corresponding to the object-of-control processing
machine 14). However, the present invention is not limited to this
embodiment. More specifically, a plurality of processing
requirements may be stored beforehand in the etching machine, and
the main computer 10 may select optimal requirements from the
requirements.
[0060] Fourth Embodiment
[0061] A fourth embodiment of the present invention will now be
described by reference to FIGS. 5A and 5B.
[0062] The present embodiment is aimed at accurately controlling
the thickness of an interlayer oxide film during an etching process
intended for smoothing the interlayer oxide film of a semiconductor
device, as in the case of the third embodiment. The following
description pertains to the difference between the third and fourth
embodiments.
[0063] In the present embodiment, an oxide film containing
impurities, such as B or P, is used for the interlayer oxide film
42. In a case where the interlayer oxide film 42 is formed from an
oxide film containing B or P, ease of smoothing can be enhanced.
Accordingly, under the manufacturing method according to the
present embodiment, the interlayer oxide film 42 can be smoothed
more readily than in the third embodiment.
[0064] In a case where the interlayer oxide film 42 is doped with
impurities, the concentration of impurities affects the rate at
which the interlayer oxide film 42 is etched. FIG. 6 is a graph
showing the influence of the concentration of P in an oxide film on
a rate at which the oxide film is etched, during a wet etching
operation using buffered hydrofluoric acid (i.e., a mixture
consisting of HF.sub.4F and HF). As shown in FIG. 6, the rate at
which an oxide film is etched increases with an increase in the
concentration of P. Accordingly, the concentration of impurities
contained in the interlayer oxide film 42 is one of the primary
factors determining the thickness of the interlayer oxide film 42
still remaining after the etching process.
[0065] As shown in FIG. 5B, in the present embodiment, the
concentration of impurities contained in the interlayer oxide film
42 is measured after deposition of the interlayer oxide film 42 and
before the formation of the resist film 44 by means of
photolithography. The resultantly-measured value is reflected in
the requirements for etching back the interlayer oxide film 42, by
means of the feedforward technique. In the present embodiment, an
impurity concentration measurement apparatus used for measuring the
concentration of impurities contained in the interlayer oxide film
42 after deposition thereof corresponds to the measurement
apparatus 12 shown in FIG. 1. Further, the etching machine used for
etching back the interlayer oxide film 42 corresponds to the
object-of-control processing apparatus 14.
[0066] The manufacturing system according to the present embodiment
measures the concentration of impurities contained in the
interlayer oxide film 42 using the impurity measurement apparatus
(i.e., the measurement apparatus 12) immediately after the
interlayer oxide film 42 is deposited on the wafer. The
resultantly-measured value is transmitted to the main computer 10,
and the value is recorded in the measurement value memory 20 along
with the ID assigned to the thus-measured wafer. When the wafer has
reached a process of etching back the interlayer oxide film 42, the
etching machine (i.e., the object-of-control processing apparatus
14) requests the main computer 10 to transmit optimal requirements.
The recipe determination section 24 of the main computer 10 sets as
processing requirements for the etching machine the optimal
requirements, which are determined on the basis of the
concentration of impurity in the interlayer oxide film 42.
Subsequently, the interlayer oxide film 42 is etched back under the
optimal requirements.
[0067] According to the manufacturing method, the thickness of the
interlayer oxide film 42 can be made uniform to high accuracy
before formation of an upper interconnection. The manufacturing
method and system according to the present embodiment enable
prevention of patterning failures in an upper interconnection, and
high-yield manufacture of a semiconductor device of stable
quality.
[0068] In the fourth embodiment, an ID is set on a per-wafer basis,
and requirements for etching the interlayer oxide film 42 are also
set on a per-wafer basis. However, the present invention is not
limited to this embodiment. Specifically, an ID may be set on a
per-lot basis, and etching requirements may be set on a per-lot
basis.
[0069] In the fourth embodiment, processing requirements are set
within the main computer 10, and the thus-set processing
requirements are transmitted from the main computer 10 to the
etching machine (corresponding to the object-of-control processing
machine 14). However, the present invention is not limited to this
embodiment. More specifically, a plurality of processing
requirements may be stored beforehand in the etching machine, and
the main computer 10 may select optimal requirements from the
requirements.
[0070] In the first through third embodiments set forth, the
requirements for etching the isolation oxide film 33 or the
interlayer oxide film 42 are determined on the basis of the
thickness of the isolation oxide film 33 or the interlayer oxide
film 42. In the fourth embodiment, the requirements for etching the
interlayer oxide film 42 are determined on the basis of the
concentration of impurities contained in the interlayer oxide film
42. However, data used for determining the requirements for etching
the isolation oxide film 33 or the interlayer oxide film 42 are not
limited to the film thickness or the concentration of impurities.
For instance, the requirements for etching the isolation oxide film
33 or the interlayer oxide film 42 may be determined on the basis
of the refractive index of the films.
[0071] Fifth Embodiment
[0072] A fifth embodiment of the present invention will now be
described by reference to FIGS. 7A through 7E.
[0073] The fifth embodiment is aimed at accurate formation of a
miniaturized interconnection pattern. In the present embodiment,
the processing described below is performed during the course of
manufacture of a semiconductor device.
[0074] As shown in FIG. 7A, an interconnection layer 46 and an
oxide film 48 are formed on the silicon substrate 31. The
interconnection layer 46 is formed from, for example, doped
polysilicon or metal material such as tungsten or tungsten
silicide. A resist film 50 which is slightly larger than a
miniaturized pattern to be formed is patterned on the oxide film 48
by means of photolithography.
[0075] The oxide film 48 is dry-etched while the resist film 50 is
taken as a mask. Subsequently, the resist film 50 still remaining
on the oxide film 48 is removed by means of oxygen plasma
processing. As a result, there is formed the wafer, as shown in
FIG. 7B.
[0076] As shown in FIG. 7C, the outer dimension of the oxide film
48 is reduced by means of wet etching. The oxide film 48 thus
reduced turns into a miniaturized pattern which cannot be formed by
means of dry etching.
[0077] As shown in FIG. 7D, the interconnection layer 46 is
dry-etched while the reduced oxide film 48 is taken as a mask.
Consequently, an interconnection 52 having a miniaturized pattern
is formed on the silicon substrate 31.
[0078] The principal reasons for causing dimensional errors in the
interconnection 52 formed through the foregoing procedures are (1)
dimensional errors in the resist film 50 formed by means of
photolithography and (2) dimensional errors in the oxide film 48
caused by side etching, which etching would arise during the dry
etching process. In the present embodiment, in order to accurately
set the final dimension of the interconnection 52 to a desired
value, dimensional errors in the resist film 50 and those in the
oxide film 48 are corrected by means of the technique to be
described below.
[0079] As shown in FIG. 7E, in the present embodiment, the resist
film 50 is formed through use of photolithography at first. Then,
the oxide film 48 is dry-etched using the resist film 50 as a mask.
After removing the resist film 50, the dimension of the patterned
oxide film 48 is measured. The resultantly-measured value is
reflected in the requirements for wet-etching the oxide film 48 by
means of the feedforward technique. In the present embodiment, the
dimension measurement apparatus used for measuring the dimension of
the oxide film 12 after removal of the resist film 50 corresponds
to the measurement apparatus 12. Further, the wet-etching apparatus
used for wet-etching the oxide film 12 corresponds to the
object-of-control processing apparatus 14.
[0080] The manufacturing system according to the present embodiment
measures the dimension of the oxide film 48 using the dimension
measurement apparatus (i.e., the measurement apparatus 12) before
the oxide film 48 is subjected to wet etching. The
resultantly-measured value is transmitted to the main computer 10,
and the value is recorded in the measurement value memory 20 along
with the ID assigned to the thus-measured wafer. In addition, when
the wafer has reached a wet-etching process, the wet etching
apparatus (i.e., the object-of-control processing apparatus 14)
requests the main computer 10 to transmit optimal requirements. The
recipe determination section 24 of the main computer 10 sets the
optimal requirements, which are determined on the basis of the
dimension of the oxide film 48, as processing requirements for the
etching machine. Subsequently, the oxide film 48 is wet-etched
under the optimal requirements.
[0081] According to the manufacturing method set forth, dimensional
errors in the resist film 50 or dimensional errors in the oxide
film 48 stemming from side etching can be absorbed by wet etching.
For this reason, the manufacturing method and system according to
the present embodiment enable considerably-accurate patterning of a
minute interconnection 52 and high-yield manufacture of a
semiconductor device of stable quality.
[0082] In the fifth embodiment, an ID is set on a per-wafer basis,
and requirements for etching the oxide film 12 are also set on a
per-wafer basis. However, the present invention is not limited to
this embodiment. Specifically, an ID may be set on a per-lot basis,
and etching requirements may be set on a per-lot basis.
[0083] In the fifth embodiment, processing requirements are set
within the main computer 10, and the thus-set processing
requirements are transmitted from the main computer 10 to the
etching machine (corresponding to the object-of-control processing
machine 14). However, the present invention is not limited to this
embodiment. More specifically, a plurality of processing
requirements may be stored beforehand in the etching machine, and
the main computer 10 may select optimal requirements from the
requirements.
[0084] Sixth Embodiment
[0085] A sixth embodiment of the present invention will now be
described by reference to FIG. 8.
[0086] FIG. 8 is a block diagram for describing the characteristic
part of the manufacturing system according to the present
embodiment. In addition to the manufacturing system described in
connection with the fifth embodiment, the manufacturing system
according to the present embodiment further comprises a recipe
correction section 54 and an elapsed-time management section 56.
The recipe correction section 54 and the elapsed-time management
section 56 can be disposed within the main computer 10 or within
the wet etching machine (i.e., within the processing apparatus
14).
[0087] The elapsed-time management section 56 is a unit for
counting the time which has elapsed since replacement of a chemical
stored in the wet etching machine with a fresh chemical. The recipe
correction section 54 is a unit for correcting the basic recipe for
wet etching in accordance with the elapsed time. A wet etching
chemical deteriorates with elapse of time. In addition, an etch
rate of wet etching changes in accordance with the deterioration of
the chemical. Therefore, it is effective for accurately etching the
oxide film 48 by means of wet etching to correct wet-etching
requirements in accordance with the time which has elapsed since
replacement of the chemical.
[0088] In the manufacturing system according to the present
embodiment, wet-etching requirements can be corrected on the basis
of the dimension of the oxide film 48 which has been dry-etched.
Further, wet-etching requirements can be corrected in accordance
with the time which has elapsed since replacement of a chemical.
The manufacturing system and method according to the present
embodiment enables the interconnection 52 to be patterned more
accurately than in the fifth embodiment.
[0089] The sixth embodiment employs two techniques in combination;
that is, the technique of reflecting the dimension of the
dry-etched oxide film 48 in the requirements for wet etching the
oxide film 48, by means of the feedforward technique; and the
technique of reflecting the time which has elapsed since
replacement of the chemical in the wet-etching requirements. The
present invention is not limited to this embodiment. More
specifically, the technique of correcting the wet-etching
requirements in accordance with the time which has elapsed since
replacement of the chemical may be used solely in isolation from
the technique of correcting the wet-etching requirements in
accordance with the dimension of the oxide film 48.
[0090] In the first through sixth embodiments, requirements for
only etching (either dry etching or wet etching) are corrected by
means of the feedforward technique. Processing which may be
corrected by means of the feedforward technique is not limited to
the above-described technique. For instance, film-growth
requirements or CMP requirements may be corrected by means of the
feedforward technique.
[0091] The present invention which has been embodied in the manner
as mentioned previously yields the following effects.
[0092] According to a first aspect of the present invention, the
state of a wafer which is an object of processing can be reflected
in the requirements for processing the wafer, by means of the
feedforward technique. Hence, the present invention enables
high-yield manufacture of a semiconductor device of stable
quality.
[0093] According to a second aspect of the present invention, the
physical quantity of a film to be processed can be reflected in the
requirements for etching the film. Accordingly, the present
invention enables accurate etching of the film.
[0094] According to a third aspect of the present invention, the
thickness of a film to be processed can be reflected in etching
requirements. Accordingly, the present invention enables accurate
etching of the film without regard to variations in the thickness
of the film.
[0095] According to a fourth aspect of the present invention, the
concentration of impurities contained in a film to be processed can
be reflected in etching requirements. Hence, the present invention
enables accurate etching of the film without regard to a difference
in etch rate due to a difference in concentration of
impurities.
[0096] According to a fifth aspect of the present invention, the
refractive index of a film to be processed can be reflected in
etching requirements. The present invention enables accurate
etching of the film without regard to a difference in etch rate due
to a difference in refractive index.
[0097] According to a sixth aspect of the present invention, the
dimension of a film to be processed can be reflected in etching
requirements. The present invention enables accurate
miniaturization of a film to a desired dimension without regard to
the dimension of the film at a point in time at which etching of
the film is commenced.
[0098] According to a seventh aspect of the present invention,
processing requirements according with a measurement value are
determined within the main computer, and the processing
requirements can be set in a processing apparatus.
[0099] According to a eighth aspect of the present invention,
processing requirements according with a measurement value can be
determined within a processing apparatus.
[0100] According to a ninth aspect of the present invention,
wet-etching requirements can be corrected in accordance with the
state of a chemical. Therefore, the present invention enables
accurate wet-etching of a film to be processed at all times,
without regard to deterioration of the chemical.
[0101] Further, the present invention is not limited to these
embodiments, but variations and modifications may be made without
departing from the scope of the present invention.
[0102] The entire disclosure of Japanese Patent Application No.
2000-349027 filed on Nov. 16, 2000 including specification, claims,
drawings and summary are incorporated herein by reference in its
entirety.
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