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Claims  |
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What is claimed is:
1. A production management system comprising:
a host computing machine serving as a scheduler which executes production
schedules for a plurality of production machines, forming a production
line, and/or articles to be processed which are objects of production
processes by the production machines based on first information on
production abilities of the machines and second information on state
quantity of the articles to be processed by the machines;
a computer associated with each production machine for distributing said
schedules to each production machine and reporting to said scheduler on
progress of said production process for each production machine;
an input means for inputting to said scheduler third information on degrees
of production progress on said production machines and/or said articles to
be processed;
a judgment means for comparing said input third information with said
production schedules and for judging if said degrees of production
progress are within predetermined allowances on said production machines
and/or said articles to be processed;
an adjustment means for adjusting said production schedule so as to match
predetermined production target if negative judgment is given by said
judgment means;
a designating means for designating at least one article to be processed
having high priority or importance, forming a first article group, from
said articles to be processed which are objects of said production
processes, the rest forming a second article group, said designated at
least one article to be processed which is an object of said execution of
said production schedules to execute a first production schedule, and of
said adjustment; and
an extraction means for extracting marker articles to be processed at a
predetermined interval from said second article group, said extracted
marker articles to be processed which are treated as said articles to be
processed in said first article group.
2. A production management system comprising:
a host computing machine serving as a scheduler which executes production
schedules for a plurality of production machines, forming a production
line, and/or articles to be processed which are objects of production
processes by the production machines based on first information on
production abilities of the machines and second information on the
quantity of the articles to be processed by the machines;
a computer associated with each production machine for distributing said
schedules to each production machine and reporting to said scheduler on
progress of said production process for each production machine;
an input means for inputting to said scheduler third information on degrees
of production progress on said production machines and/or said articles to
be processed;
a judgment means for comparing said input third information with said
production schedules and for judging if said degrees of production
progress are within predetermined allowances on said production machines
and/or said articles to be processed;
an adjustment means for adjusting said production schedule so as to match
predetermined production target if negative judgment is given by said
judgment means;
a first virtual production lane having a distribution ratio of resources in
which production process of said at least one article to be processed
having high priority or importance is performed, and
a second virtual production lane in which production process of the rest of
said articles to be processed in said production line other than said at
least one article to be processed having high priority or importance is
performed;
said first and second virtual production lanes being assigned in advance,
and wherein said adjustment means adjusts said schedules so that said
distribution ratio of resources relating to said first virtual production
lane increase when a result of said judgment by said judgment means is
negative.
3. A production management system comprising:
a host computing machine serving as a scheduler which executes production
schedules for a plurality of production machines, forming a production
line, and/or articles to be processed which are objects of production
processes by the production machines based on first information on
production abilities of the machines and second information on the
quantity of the articles to be processed by the machines;
a computer associated with each production machine for distributing said
schedules to each production machine and reporting to said scheduler on
progress of said production process for each production machine;
an input means for inputting to said scheduler third information on degrees
of production progress on said production machines and/or said articles to
be processed;
a judgment means for comparing said input third information with said
production schedules and for judging if said degrees of production
progress are within predetermined allowances on said production machines
and/or said articles to be processed;
an adjustment means for adjusting said production schedule so as to match
predetermined production target if negative judgment is given by said
judgment means;
a designating means for designating at least one article to be processed
having high priority or importance, forming a first article group, from
said articles to be processed which are objects of said production
processes, the rest forming a second article group, said designated at
least one article to be processed which is an object of said execution of
said production schedules to execute a first production schedule, and of
said adjustment; and
a scheduling means for executing a second production schedule for said
articles processed in said second article group, said second production
schedule which is shorter than said first production schedule for said
articles to be processed in said first article group.
4. The production management system as claimed in claim 3, further
comprising:
an extraction means for extracting marker articles to be processed at a
predetermined interval from said articles to be processed in said second
article group, and
wherein said extracted marker articles to be processed are treated as said
articles to be processed in said first article group.
5. The production management system as claimed in claim 3, wherein said
second production schedule includes information on completion date of said
articles to be processed in said second article group, and
said system further comprising:
a priority changing means for checking if said completion date in said
information is in time for a predetermined delivery date, and changing
priority of said articles to be processed in said second article group so
that said articles to be processed in said second article group are
treated as said articles to be processed in said first article group.
6. The production management system as claimed in claim 5, further
comprising:
an extraction means for extracting marker articles to be processed at a
predetermined interval from said articles to be processed in said second
article group, and
wherein said extracted marker articles to be processed are treated as said
articles to be processed in said first article group.
7. A production management method using a scheduler, comprising the steps
of:
providing first information on production abilities of a plurality of
production machines forming a production line and second information on
the quantity of articles to be processed that are objects of production
processes by said production machines;
designating at least one specified article to be processed as an object of
first scheduling by said scheduler from among said articles to be
processed that are objects of said production processes and inputting this
information to said scheduler, said at least one specified article being
one member selected from the group consisting of an article to be
processed having high importance and an article to be processed having
high priority;
designating the rest of said articles to be processed in said production
line other than said at least one article to be processed having high
priority or importance as objects of second scheduling by said scheduler;
forming a first virtual production lane having a distribution ratio of
resources in which a production process of said at least one article to be
processed having high priority or importance is performed;
forming a second virtual production lane in which a production process of
the rest of said articles to be processed in said production line other
than said at least one article to be processed having high priority or
importance is performed;
executing first and second production schedules for said at least one
designated article in said first virtual production lane and for said
articles to be processed in said second virtual production lane,
respectively, both based on said first and second information;
monitoring production progress of said at least one designated article in
said first virtual production lane, based on said executed production
schedules; and
automatically adjusting said first and second production schedules for said
at least one designated article in said first virtual production lane so
that said distribution ratio of resources relating to said first virtual
production lane increases if said production progress of said at least one
designated article in said first virtual production lane is delayed.
8. A production management method using a scheduler, comprising the steps
of:
providing first information on production abilities of a plurality of
production machines forming a production line and second information on
the quantity of articles to be processed that are objects of production
processes by said production machines;
designating at least one specified article to be processed as an object of
long period scheduling from among said articles to be processed that are
objects of said production processes, and the rest of said articles to be
processed that are objects of said production processes as objects of
short period scheduling, and inputting this information to said scheduler;
executing long period production schedules and short period production
schedules according to a kind of said scheduling for said designated
articles to be processed, based on said first and second information;
executing a production schedule for a whole production system by
synthesizing said executed long term production schedules and said
executed short period production schedules;
monitoring production progress of said at least one specified articles to
be processed and the rest of said articles to be processed that are
objects of production processes, based on said executed production
schedule for said whole production system; and
adjusting said production schedule for said whole production system with
respect to said articles to be processed whose production progresses are
delayed, based on results of said monitoring,
wherein said at least one specified article is one member selected from the
group consisting of an article to be processed having high importance, an
article to be processed having high priority, and a marker article to be
processed.
9. A production management method using a scheduler, comprising the steps
of:
providing first information on production abilities of a plurality of
production machines forming a production line and second information on
the quantity of articles to be processed that are objects of production
processes by said production machines;
providing first and second schedulers which perform first and second
schedulings, respectively;
said first scheduling comprising the steps of:
designating at least one specified article to be processed as object of
long period scheduling from among said articles to be processed that are
objects of said production processes, and inputting this information to
said first scheduler;
executing long period production schedules for said designated at least one
specified articles to be processed, based on said first and second
information;
monitoring production progresses of said at least one specified articles to
be processed, based on said executed long period production schedule;
automatically adjusting said long period production schedule with respect
to said articles to be processed whose production progresses are delayed,
based on results of said monitoring; and
transferring said executed or adjusted long period production schedule to
said second scheduler; and said second scheduling comprising the step of:
executing a short period production schedule for whole articles to be
processed that are object of said production processes, based on said
first and second information, using said long term production schedules
transferred from said first scheduler.
10. The production management method as claimed in claim 9, wherein said at
least one specified article is one member selected from the group
consisting of an article to be processed having high importance, an
article to be processed having high priority, and a marker article to be
processed. |
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Claims |
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Description |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a production management system for
controlling the production of various industrial products such as
semiconductor components, e.g., LSI, clothes, and automobiles. The term
"production management" or "management of manufacture" as used herein
includes (1) so-called scheduling for the determination of order of
manufacture of multi-kind products depending on respective process steps
or degrees of urgency, (2) monitoring progressive condition of
manufacture, and (3) collection of processing data upon manufacture.
2. Description of the Prior Art
Conventional production management system will be described taking an
example of manufacturing process steps for manufacturing an LSI.
FIG. 1A is a flow chart schematically illustrating a manufacturing
procedure for manufacturing an LSI, and FIG. 1B is a cross sectional view
showing a semiconductor substrate being processed for manufacturing a
bipolar LSI, with illustrating in more detail the step of photolithography
illustrated in FIG. 1A.
Generally, various technologies are applied to process a monocrystalline
wafer at least once, and up to several tens times on the larger side in
order to make up a fine structure on the semiconductor substrate so that
it can exhibit desired functions, thus completing manufacture of an LSI.
The technologies include formation of an insulation film such as an oxide
film/nitride film, photolithography, diffusion by heat treatment, pattern
formation by photolithography, film formation by vapor deposition or
sputtering, etching, introduction of impurities by ion implantation,
scribing (division), mounting, bonding, etc. As illustrated in FIG. 1A,
LSI manufacturing procedure includes a plurality of steps of processing a
monocrystalline wafer 1, for example, for obtaining a bipolar LSI, steps
of oxidation 2, photolithography 3, burying diffusion 4, epitaxial growth
5, oxidation 6, . . . , photolithography 7, base diffusion 8,
photolithography 9, emitter diffusion 10, photolithography 11, metal
deposition 12, photolithography 13, alloying 14, scribing 15, mounting 16,
bonding/inclusion 17, and product test/reliability test 18 to obtain a
product 19, and for obtaining a MOS LSI, steps of photolithography 20,
source drain diffusion 21, epitaxial growth 22, oxidation 23, . . . ,
photolithography 24, metal deposition 25, and photolithography 26, instead
of the steps 3 to 13 in the manufacture of a bipolar LSI, to obtain the
product 19.
Each technology in the procedure illustrated in FIG. 1A is subdivided into
several treatments. For example, the photolithography is comprised, as
illustrated in FIG. 1B, by (a) coating of a resist which is a
photosensitive composition: a silicon substrate 30 having an oxide layer
31 is provided with a photoresist film 32 on the surface of the oxide
layer; (b) alignment of a mask/exposure: a mask 33 having an imagewise
pattern is arranged in alignment above the photoresist film 32, light is
irradiated through the mask 33 so that the photoresist film 32 is
imagewise exposed, and the exposed portion is dissolved in a developer to
transfer the pattern; (c) pattern formation by development: patterning is
performed by photolithography (d) processing by etching: the exposed
portion of the oxide film is etched off, etc. Unit of such procedure is
usually called "step". LSIs can be fabricated by repeating such steps
several hundreds of times. List of the procedure of the manufacturing
process steps is a "process table" as shown in FIG. 2. The process table
describes contents of process which include at least machines used,
recipes, etc. in the order of process.
The process table is assigned to each lot, i.e., process unit: usually for
each cassette, or for each sheet in case of a sheet-fed process), and LSIs
can be fabricated by performing the process in order as prescribed in the
process table. What is characteristic here is that in the process, the
same machine is used more than once, usually, many times, under different
conditions or recipes. In case different types of machines are used or
different types of products are to be fabricated, fabrication in the same
step proceeds under different recipes. The term "recipe" as used herein
refers to conditions including not only manufacturing conditions such as
oxidation or annealing temperature, gas flow rate, and kind of mask used
upon exposure, but also testing conditions such as position at which
measurement of size is performed. Thus, the manufacturing process for LSI
is a very complicated manufacturing line whose control is far more
complicated since it involves many elements and a permutation/combination
of many elements must be controlled.
Recently, diversification of products, and immediate response to needs of
customers have been desired not only in the field of LSI but also in
various other fields. Accordingly, demands in LSI production management
are shifting from management for increasing the production efficiency by
automation of transportation to delivery date management, and TAT (turn
around time) management. In accordance with increased diversification of
products, there has been an increasing tendency that many types of
products are manufactured in a single production line. In addition, not
only products differ in their throughputs but also processes differ in
their importance and priority from kind to kind. Importance depends on
added value such as design costs for masks, etc., manufacture costs for
special steps, and is determined usually when normal lots are input. On
the other hand, priority, which indicates which one should precede when a
plurality of steps are competitively awaiting for a process to be
performed in the same machine, is determined depending on allowance till
delivery date. Thus, even when a lot has been assigned low priority since
a full allowance in time till delivery date was expected originally, it
will be often the case that the priority of the lot must be increased
because of a delay from the previous arrangement or schedule which
occurred in the midway, or conversely, the priority of the lot must be
decreased due to the occurrence of ample time margins for delivery.
It is useful to collect and monitor process execution data not only for
preventing the occurrence of faulty products but also for the analysis of
causes of troubles when such occur. Therefore, it is indispensable to
collect process data including test data. It is desirable but not
mandatory to collect the process data automatically from the machines.
Upon collection of process data and test data, the same machine is used
many times repeatedly in the step concerned, and hence key (keyword)
information is attached to the data that enables identification of a
particular step in a particular lot, i.e., indication of the position of
the step concerned in the process table, before the data can be stored. It
is a simpler and easier way to use a process schedule being executed as
the key information. More specifically, upon lot processing, a particular
lot is recognized by a bar code reader, the process schedule of the lot is
received through a network communication, and stored together with the
process data in a data base. Alternatively, a magnetic card is transported
together with a lot and the card is read to obtain a key information,
which is then stored together with process data in a database. These
methods are featured in that they can serve as lot tracking management as
well. As a procedure for such a conventional production line management,
there can be cited, one as illustrated in FIG. 3. In the conventional
example illustrated in FIG. 3, the results of schedule in the form of a
schedule table (program) is distributed to a computer, and an operator
executes the process in accordance with the work instruction based on the
program. Processed records such as the process data are fed back to the
scheduler by collection of on-line data in which such data are transmitted
directly from the manufacture machines and test machines, respectively, or
by off-line input of progress data from a terminal by the operator to
control the progress and reflect the progress condition in next
scheduling.
Mass production line, in which the same kind of products are manufactured
in large amounts, mostly uses, as a manufacturing method, a
first-in/first-out (FI/FO) heaping method by which older lots selected
from jamming lots that stay in each machine in the line and await for a
process are processed in order chronologically with the oldest one being
processed at first, or a "kanban" system in which excessiveness or
insufficiency of received lots is displayed visually. Results of the
processing are given indicating which step in which lot the results are
concerned with, in situ with keyboard or bar code reading information,
before they can be stored in a data base.
In this case, the work-in-process volume of the lots in the line is
controlled. For example, SEMI Technology Symposium 92, p. 129 describes a
method in which such a control of work-in-process volume is applied to
average process volume in each machine to increase the rotation ratio of
lot processing.
This method involves setting up two kinds of limitation values of work
volume for each step, one being a limitation value for stopping receipt of
lots in the step concerned, and the other a limitation value for
restarting the stopped step. When the work volume of the step exceeds the
set value, receipt of lots in the step is stopped. When the work volume
decreases to below the set up limitation value, receipt of lots is started
again. Thus, the work volume is controlled. However, in this case, since
it is impossible to grasp process schedules for respective steps in each
lot, delivery date management and TAT (turn-around-time, i.e., number of
days till completion of the lot) control are difficult.
On the other hand, in a production line called ASIC-LSI (Application
Specific Integrated Circuits-LSI), as shown in FIG. 4, there exist many
kinds of lots whose priority of process and importance differ from lot to
lot. For example, special order products and products of special
specifications are small in throughput, and require high designing and
production costs, which assigns high importance whereas mass production
products such as memories, and general-purpose products are assigned low
importance. Among ASIC-LSI, LSIs using full custom cells, or standard
cells, are given high importance since specialized mask patterns must be
used from the substrate step. In the case of Gate array LSIs, however,
common substrates are used, and thus are given low importance originally
but high priority is assigned after they enter the wiring step using a
specialized mask pattern. On the other hand, the priority of a lot is
often changed as a result of monitoring of the allowance in time till the
delivery date, and thus varies according as the progress of the processing
of the lots. Therefore, the priority of lots changes along with the
progress of the processing of the lots.
The time passing from the input of products to their completion, i.e.,
turn-around-time (TAT), varies depending on the number of lots input in
the line. If products of different priorities coexist, those having lower
priorities are preceded by those having higher priorities, and process of
the lower priority products is deferred. For this reason, mere judgment as
to whether or not it will be in time for a delivery date by estimating
progress for each lot based on the number of lots worked-in in the machine
and process time, as has been conventionally adopted, results in failure
of precise estimation of date on which products are completed. Then, in
order to control the date of completion of lots having higher priority or
importance (hereinafter, referred to as "TAT-controlled lots") so as to be
in time for a delivery date, and in addition, to prepare a key information
for collecting data, it is necessary to monitor progress of lots, and
executing not only a regular or periodic scheduling, e.g., once a day, but
also an irregular scheduling to make up difference or gap in progress due
to troubles of the machine or delay in progress in order to gradually
renew the process schedule. That is, the progress is monitored, the
priority as to which lot should be processed first is changed based on the
process results thus obtained, and the remaining scheduling other than has
already been processed must be executed taking into consideration various
factors such as working period of machines (information on disorder,
etc.), maintenance conditions, and working conditions of operators. To
perform a production management using such a scheduling, all the lots in
the line must be divided into steps, judgment must be made as to whether
machines (in some instances operators in charge) are available, and a
process schedule reflecting priority of each lot must be executed. In
particular, in the production of LSIs, many of the steps require
continuity with preceding steps (i.e., must be processed within a
predetermined time), and hence in order to accurately estimate a delivery
date, it is necessary to precisely execute a process start time schedule
for each step in each lot with checking which time range is actually
available for operation.
However, when it is intended to execute such a process schedule, there
exist many combinations of machines and operators and combinations taking
continuity with subsequent steps into consideration since there are a
plurality of machines of the same kind. Therefore, in a production
management system, memory size and calculation time for executing a
schedule allocating each step in all the lots while checking working
conditions of machines and operators (non-working period range) increases
with increased numbers of lots and machines (further including number of
operators, if operators are to be taken into consideration), and in
particular, use of a large number of lots requires a huge volume of memory
and a long calculation time.
SUMMARY OF THE INVENTION
An object of the present invention is to shorten a scheduling time in a
production line where there coexist high priority lots or high importance
lots that require controlled progress together with lots whose priority
and importance each are not so high as compared with others, and thus
enabling progress management of a production line and estimation of
completion date of high priority lots and/or importance.
Another object of the present invention is to enable progress management of
low priority lots.
Further object of the present invention is to enable application to a
production line of which number of production lots and number of kinds of
products are large.
(1) Therefore, according to a first aspect of the present invention, there
is provided a production management system having a scheduler which
executes production schedules for a plurality of production machines,
forming a production line, and/or articles to be processed which are
objects of production processes by the production machines based on first
information on production abilities of the machines and second information
on state quantity of the articles to be processed by the machines, in
which the scheduler comprises: an input means for inputting third
information on degrees of production progress on the production machines
and/or the articles to be processed; a judgment means for comparing the
input third information on the degrees of production progress with the
production schedules and for judging if the degrees of production progress
are within predetermined allowances on the production machines and/or the
articles to be processed; and an adjustment means for adjusting the
production schedule so as to match predetermined production target if
negative judgment is obtained.
(2) Here, the production management system as described in (1) above may
further comprise: a designating means for designating at least one article
to be processed having high priority or importance, forming a first
article group, from the articles to be processed which are objects of the
production processes, the rest forming a second article group, and in
which the designated at least one article to be processed is an object of
the execution of the production schedules to execute a first production
schedule, and of the adjustment.
(3) The product ion management system as described in (1) above may further
comprise: a first virtual production lane in which production process of
the at least one article to be processed having high priority or
importance is performed, and a second virtual lane in which production
process of the rest of the articles to be processed in the production line
other than the at least one article to be processed having high priority
or importance is performed, the first and second virtual lanes being
assigned in advance, and in which the adjustment means adjusts the
schedules so that distribution ratio of resources relating to the first
virtual lane when result of the judgment by the judgment means is
negative.
(4) The production management system as described in (2) above may further
comprise: an extraction means for extracting marker articles to be
processed at a predetermined interval from the second article group, and
in which the extracted marker articles to be processed are treated as the
articles to be processed in the first article group.
(5) The production management system as described in (2) above may further
comprise: a scheduling means for executing a second production schedule
for the articles processed in the second article group, the second
production schedule being shorter than the first production schedule for
the articles to be processed in the first article group.
(6) The production management system as described in (5) above may further
comprise: an extraction means for extracting marker articles to be
processed at a predetermined interval from the articles to be processed in
the second article group, and in which the extracted marker articles to be
processed are treated as the articles to be processed in the first article
group.
(7) The second production schedule as described in (5) above may include
information on completion date of the articles to be processed in the
second article group, and the system may further comprise: a priority
changing means for checking if the completion date in the information is
in time for a predetermined delivery date, and changing priority of the
articles to be processed in the second article group so that the articles
to be processed in the second article group are treated as the articles to
be processed in the first article group.
(8) The production management system as described in (7) above may further
comprise: an extraction means for extracting marker articles to be
processed at a predetermined interval from the articles to be processed in
the second article group, and in which the extracted marker articles to be
processed are treated as the articles to be processed in the first article
group.
(9) According to a second aspect of the present invention, there is
provided a production management method using a scheduler which performs
scheduling in order to execute production schedules for a plurality of
production machines, forming a production line, and/or articles to be
processed which are objects of production processes by the production
machines based on first information on production abilities of the
machines and second information on state quantity of the articles to be
processed by the machines, in which the method comprises the steps of:
designating at least one specified article to be processed as object of
the scheduling from among the articles to be processed being objects of
the production processes and inputting this information; executing
production schedules for the at least one designated article to be
processed; monitoring production progress of the at least one designated
article to be processed based on the executed production schedules; and
automatically adjusting the production schedules for the at least one
designated article to be processed if the production progress of the at
least one designated article to be processed is delayed.
(10) Here, in the production management method as described in (9) above,
the at least one specified article may be one member selected from the
group consisting of an article to be processed having high importance, an
article to be processed having high priority, and a marker article to be
processed.
(11) According to a third aspect of the present invention, there is
provided a production management method using a scheduler which performs
scheduling in order to execute production schedules for a plurality of
production machines, forming a production line, and/or articles to be
processed which are objects of production processes by the production
machines based on first information on production abilities of the
machines and second information on state quantity of the articles to be
processed by the machines, wherein the method comprises the steps of:
designating at least one specified article to be processed as object of
long period scheduling from among the articles to be processed being
objects of the production processes, and the rest of the articles to be
processed being objects of the production processes as object of short
period scheduling, and inputting this information; executing long period
production schedules and short period production schedules according to
kind of the scheduling for the designated articles to be processed;
executing a production schedule for whole production system by
synthesizing the executed long term production schedules and the executed
short period production schedules; monitoring production progress of the
at least one specified articles to be processed and the rest of the
articles to be processed being objects of production processes, based on
the executed production schedule for the whole production system; and
adjusting the production schedule for the whole production system with
respect to the articles to be processed whose production progresses are
delayed, based on results of the monitoring.
(12) Here, in the production management method as described in (11) above,
the at least one specified article may be one member selected from the
group consisting of an article to be processed having high importance, an
article to be processed having high priority, and a marker article to be
processed.
(13) According to a fourth aspect of the present invention, there is
provided a production management method using a scheduler which performs
scheduling in order to execute production schedules for a plurality of
production machines, forming a production line, and/or articles to be
processed which are objects of production processes by the production
machines based on first information on production abilities of the
machines and second information on state quantity of the articles to be
processed by the machines, wherein the method comprises the steps of:
providing a first scheduler which performs a first scheduling, and a
second scheduler which performs a second scheduling; the first scheduling
comprising the steps of: designating at least one specified article to be
processed as object of long period scheduling from among the articles to
be processed being objects of the production processes, and inputting this
information; executing long period production schedules for the designated
at least one specified articles to be processed; monitoring production
progresses of the at least one specified articles to be processed, based
on the executed long period production schedule; automatically adjusting
the long period production schedule with respect to the articles to be
processed whose production progresses are delayed, based on results of the
monitoring; and transferring the executed or adjusted long period
production schedule to the second scheduler; and the second scheduling
comprising the step of: executing a short period production schedule for
whole articles to be processed being object of production, using the long
term production schedules transferred from the first scheduler.
(14) Here, in the production management method as described in (13) above,
the at least one specified article may be one member selected from the
group consisting of an article to be processed having high importance, an
article to be processed having high priority, and a marker article to be
processed.
In the first and ninth embodiments of the present invention, objects to be
processed which are delayed in production progress are detected, and
production schedule is automatically corrected to decrease number of
inputting operations by users so that the time necessary for scheduling
can be reduced.
In the second embodiment of the present invention, objects to be processed
which are to be covered by scheduling are limited to reduce the number of
individuals which are objects of scheduling and thus shorten time for
scheduling.
In the third embodiment of the present invention, two production pseudo
lines are provided, one being a production pseudo line of an object to be
processed for performing progress management on a scheduler, and another
being a production pseudo line of other objects to be processed for
performing progress management on the scheduler, and proportions of
allotment of resources, for example, number of operators, number of
production machines, etc. are made variable to dissolve delay in progress.
In the fourth embodiment of the present invention, marker objects to be
processed are selected are sampled from among objects to be processed
which are not covered by scheduling and such sampled objects are subjected
to scheduling so that progress of the total objects to be processed but
not subjected to scheduling can be inferred.
In the fifth and eleventh embodiment of the present invention, a long
period production scheduling is executed for objects to be processed on
which progress management is performed while a short period production
scheduling is executed for objects to be processed on which no progress
management is necessary, thus reducing the amount of information to be
scheduled.
In the seventh embodiment of the present invention, progress on objects to
be processed having a low priority is also checked by means of a short
period production scheduling, and the priority of the objects to be
processed which are overdue is deemed higher, thereby reducing delay in
progress.
In the thirteenth embodiment of the present invention, a production
schedule only for particular objects to be processed having high
priorities is executed using a special scheduler, and progress management
is carried out independently of a controller which executes a schedule on
the whole objects to be processed.
The above and other objects, effects, features and advantages of the
present invention will become more apparent from the following description
of embodiments thereof taken in conjunction with the accompanying drawings
.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a flow chart illustrating a production procedure for an LSI;
FIG. 1B is a cross sectional view showing a procedure of photolithography
shown in FIG. 1A;
FIG. 2 is a chart showing an example of a process table for fabricating an
LSI;
FIG. 3 is a flow chart illustrating a procedure of production line
management;
FIG. 4 is a diagram illustrating how to divide progressed lots from
non-progressed lots;
FIG. 5 is a diagram illustrating contents of production according to a
first embodiment of | | |
