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MESMigrationStrategies

White Paper

Critical Manufacturing, 2015

Migration Motivation & Goals

Migration Strategies

Migration Strategy Selection Critical Factors

Migration Strategies Overview

Big Bang

Phased Introduction

Parallel Systems

Migration Strategies Comparison

2

3

3

4

5

6

9

11

Migration Planning

Migration Definition

Migration Preparation

Migration Execution

Migration Closure

12

13

14

15

16

Migration Motivation & Goals

2

A MES migration project

represents a big endeavor

for any organization as it

involves a significant

amount of time, cost, risk

and it involves many

stakeholders within the

company. It’s critical for

the success of the

migration project to get

commitment and

engagement of the

different affected

departments.

A MES migration must be grounded

on a solid business case which

typically involves a combination of

the following three factors:

1. Take advantage of new

products & technologies (lower

total cost-of-ownership, new

functionality, easier to use,

faster).

2. Increase corporate application

harmonization with the

expectation to reduce costs by

reducing diversity and

increasing re-utilization.

3. Address software & hardware

end-of-life, addressing the risk

of running out of support in the

case of an incident or hardware

failure.

From a business point-of-view, the

expectation is that after the

migration is completed, the

organization will reap a combination

of the following benefits:

1. Cost reduction and/or

productivity improvement

derived from:

a) Total cost of ownership

reduction

b) Taking advantage of new

functionality and features

c) Deploying faster, easier to

maintain and to use systems

2. Risk reduction by ensuring

business continuity through

long-term product support

(hardware and software).

It’s worth mentioning that it may not

be possible to take the full

advantages of the new MES

immediately after migration, as it’s

often the case that a one-to-one

migration is necessary as a stepping

stone towards the migration to a

new MES. This point is elaborated in

more detail in the next chapters of

this document.


3

Table 1 - Migration types and

typical critical factors relative weight

The decision on which migration

strategy to use is driven primarily by

three factors:

1. Time - how much time does

the project take from start-to-

finish, including the pre-

migration, migration and post-

migration phases.

2. Risk - how much risk and risk

exposure (probability x cost) is

associated.

3. Cost - how much costs are

involved in the planning and

execution of the selected

strategy, including opportunity

costs (e.g.: downtime).

The three different factors above

must be weighted and analyzed in

relative terms among the different

possible migration strategy

alternatives. Each migration specific

case will weigh the three factors

above differently depending

typically on the different levels of:

1. Interdependence - how much

inter-action and interfaces

exist with other systems and

applications.

2. Automation - the level of

automation for which the MES

is responsible for.

3. Downtime Impact - how

much a unit of time that the

MES is unavailable costs to the

business.

For illustration purposes, Table 1

captures some types of MES

migration, assuming in all cases,

that there is some kind of MES in

place (even if based on paper)

and that there is some regular

production volume in place.

SYSTEM IN PLACE TYPICAL CHARACTERIZATIONTYPICAL RELATIVE

WEIGHTS

Paper or Excel Based MES

Interdependence: Low

Automation: Low

Downtime Impact: Low-to-Medium

1. Cost

2. Time

3. Risk

Stand Alone MES Application

Interdependence: Low

Automation: Low

Downtime Impact: Medium-to-High

1. Cost

2. Time

3. Risk

Integrated MES Application, Low Automation

Interdependence: High

Automation: Low

Downtime Impact: Medium-to-High

1. Cost / Risk

2. Risk / Cost

3. Time

Integrated MES Application, High Automation

Interdependence: High

Automation: High

Downtime Impact: High

1. Risk

2. Cost

3. Time

Migration Strategy

Selection Critical Factors

4

Table 2 - Migration strategies overview



Overview

There are basically three different

types of MES migration strategies,

each with its own of advantages

and disadvantages:

1. Big Bang - represents a point

in time where the old MES is

switched off and the new MES

is switch on.

2. Phased Introduction - the

new MES is progressively

introduced, either:

a) Phased by Manufacturing

Unit - area by area, step by

step, equipment by

equipment.

b) Phased by MES Function -

MES function by function.

c) Phased by Lot - lot by lot.

3. Parallel Systems - both the

old MES and the new MES

are used in parallel until

enough confidence is built in

the new MES.

Table 2 describes these migration

strategies at a high-level.

Each strategy is further detailed in

the next sections assuming for

illustration purposes that it’s

intended to maintain the existing

Operation GUI, the Equipment

Integration Layer as well as the

existing Reporting and Data

Analysis solution in a high-

automation environment.

MIGRATION STRATEGY DESCRIPTION

Big Bang Switch Off Legacy MES, Switch On New MES

Data will reside in one system only at all times

Phased Introduction

By Manufacturing Unit

Area/Step/Equipment by Area/Step/Equipment phased

introduction

Old and new MES systems will co-exist for some time, with data

split between the two systems and material being shipped from

one system to another

Phased Introduction

By MES Function

MES function-by-function (e.g.: SPC; Recipe Management or

Maintenance Management)

Old and new MES systems will co-exist for some time, but with

different functional responsibilities

Phased Introduction

By Lot

Two independent systems exist for the duration of migration. Some

lots are started in the new system while other lots are started in

legacy system

Common shared objects (Equipment, Containers, Reticles, …) must

be synchronized between the two systems

Parallel Systems

Two systems are run in parallel to make sure that everything works

as expected and after some time the new MES system is designated

as master and the legacy system is switched off

Data will reside in both systems at the same time (one system is

designated as the Master and another the Slave)

The Big Bang strategy consists of

making all the necessary

preparations and testing so that the

old MES system can be switched off

and the new MES system can be

switched on. The simplicity of this

strategy as well as the short

migration switching time makes this

strategy attractive. However,

because of all the

interdependencies and the difficulty

of re-creating all the conditions of a

live production environment, this

strategy carries a lot of risk.

Figure 1 captures the

Manufacturing IT landscape before

migration. The grey boxes represent

the old MES to be replaced by a

new one. As part of the migration,

some of the existing satellite

manufacturing applications will be

replaced by the new MES, but some

applications may remain either

retaining the complete functionality,

or just by using a subset.

Once the interfaces have been

adjusted for the new MES and the

system has been thoroughly tested

(including the migration rehearsal

procedure), once a downtime slot

has been arranged with the fab

management, the migration

procedure is carried out. The

migration procedure typically

involves data synchronization

procedures as well as some

application shutdowns,

configuration file changes and

application start-ups.

After the successful completion, the

landscape will look similar to Figure

2. Light blue boxes represent the

new MES while black boxes

represent applications or portions

of applications that have been

switched off. Immediately after the

migration, any new functionality

available in the new MES can be

used right away.

5


Big Bang

Figure 1 - Manufacturing IT

landscape before migration

ERP

Legacy Master

Data GUIOperation GUI

Legacy

MES

Other

Manufacturing

Applications

Other

Manufacturing

Applications

Equipment

Integration

Equipment

Integration

Equipment

Integration

REPORTING /

ANALYSIS

DATABASES

ERP

Other

Manufacturing

Applications

Figure 2 - Manufacturing IT

landscape after migration

Legacy Master


Legacy

MES

Other

Manufacturing

Applications

Equipment

Integration

Equipment

Integration

Equipment

Integration

New Master

Data GUI

New

MES

REPORTING /

ANALYSIS

DATABASES

ERP

Other

Manufacturing

Applications

6

Events

Client Side

Server Side

Client Calls

ERP A2A

InterfacesNew MES

ETL

REPORTING /

ANALYSIS

DATABASES

Legacy MES

LEGACY MES

DBNEW MES

DB

Routing Layer

Figure 3 - Phased Introduction

migration architecture


Phased Introduction - Phased Introduction by Manufacturing Unit

The Phased Introduction by

Manufacturing Unit consists of

slowly introducing the new MES

area by area, step by step or

equipment by equipment. Usually

starting from the first parts of the

process (area, step or equipment),

the new MES system is introduced

and the old system is switched off.

This procedure continues gradually

until the new MES system is used for

the whole factory. If for some

reason, a critical problem is

detected, the areas where the new

MES system was deployed last are

rolled back to the old MES.

With the Phased Introduction by

Manufacturing Unit migration

strategy, the client applications must

be able to work interchangeably

with either the old or the new MES

system. The best way to accomplish

this is to add a central routing layer

within the existing middleware

infrastructure. This routing layer,

depicted in Figure 3, must have the

business logic to determine when to

call one system and when to call the

other.

In some industries, like

semiconductor front-end, there is

one particular challenge which is

presented in the Phased

Introduction by Manufacturing

Unit migration strategy.

The manufacturing process itself

contains several loops (in the

case of semiconductor front-end,

one loop for each layer) as

illustrated in Figure 5. Therefore,

depending on the granularity of

the Manufacturing Unit, it can be

a case that a lot may leave one

MES system to enter another one

and then come back. While it’s

possible to handle this situation,

because of the additional

complexity, it should be avoided

whenever possible.

ERP

Other

Manufacturing

Applications

Figure 4 - Phased Introduction by

Manufacturing Unit migration strategy

Legacy Master


Legacy

MES

Other

Manufacturing

Applications

Equipment

Integration

Equipment

Integration

Equipment

Integration

New Master

Data GUI

New

MES

REPORTING /

ANALYSIS

DATABASES

ERP

Other

Manufacturing

Applications

7


Phased Introduction - Phased Introduction by Manufacturing Unit

Routing Layer

Other remarks, applicable to the

Phased Introduction by

Manufacturing Unit

(area/step/equipment):

• It’s not a requirement, but it’s

possible to freeze the master

data changes for the duration

of migration in order to avoid

master data consistency

problems.

• Because of the

interchangeability requirement,

typically, the goal of the

migration is to have the same

functionality as it existed in the

old MES system, which also

represents the minimum

common set of functionality.

• It requires a ship/receive of

Material between the two MES

systems.

• Data is spread between two

systems as the master system

changes over time, with the

new MES increasing in scope.

• Reporting (including Material

history) can be an issue, if data

is not consolidated into a single

reporting database.

NEW MES

Step 1 Step 2 Step 3

Figure 5 - Phased Introduction by

Manufacturing Unit migration strategy

in a process with loops

LEGACY MES

Step 4 Step 5 Step 6

8


Phased Introduction - Phased Introduction by MES Function

The Phased Introduction by MES

Function migration strategy is a

variation of the Phased Introduction

approach where functional portions

of the old MES are replaced by

some portions of the new MES.

This strategy deserves some words

of caution. While it’s possible to

break-up some of the MES function

so that they work well separately,

e.g.: Resource Tracking,

Maintenance Management, Recipe

Management, Carrier Management,

SPC; when it comes to Material

Tracking, there are very deep

dependencies with the Master Data

system (mainly for process flow

routing) which makes it difficult to

separate. In addition, because the

new function is introduced globally

at the fab level, these represent in

fact some form of Big-Bang,

especially when migrating the

Material Tracking functionality.

Typically this approach is

introduced in a Big Bang way when

adding new functionality or in a

Phased Introduction By

Manufacturing Unit style when

replacing existing functionality for

reasons of risk reduction.

BIG BANG PHASED INTRODUCTION PARALLEL SYSTEMS

Phased Introduction - Phased Introduction by Lot

The Phased Introduction by Lot

consists of starting some lots in the

new MES system (for instance, lots

of a particular product) while

keeping the old lots and some of

the new lots in the old MES. This

approach requires that shared

entities are modeled, synchronized

and interchangeable between the

two systems, for example: carriers,

consumables, reticles and equipment.

For the complete duration of

migration, WIP will be split into two

MES systems. In addition, control of

shared entities (e.g.: resources)

needs to be constantly delegated

from one system to another forcing

both a routing decision and a

synchronization layer to maintain

the state of the shared entities

synchronized in both systems.

This strategy can be seen as a Big

Bang for the new lots, and given the

synchronization and

interchangeability requirements, as

well as difficulty in having a baseline

and an easy rollback procedure

which carries significant risk, this

strategy is not recommended for

the great majority of the migration

scenarios.

Events

Client Side

Server Side

Client Calls

ERP A2A

InterfacesNew MES

ETL

REPORTING /

ANALYSIS

DATABASES

Legacy MES

LEGACY MES

DB

NEW MES

DB

Synchronization Layer

9

Figure 6 - Parallel Systems

migration architecture


Parallel Systems

Master - Slave

switch must be

prepared

Master - Slave

switch must be

prepared

The Parallels Systems strategy

consists in having the old and the

new MES systems running in

parallel. For the duration of the

migration, the old MES is

designated as the Master and the

new MES as the Slave. After enough

confidence has been built into the

new system, the new MES can

become the Master and the old

MES can simply be switched-off.

Instead of switching-off the old MES

when the new MES becomes the

Master it’s also possible to set it as

Slave. This provides additional

safety and flexibility but comes at

an additional cost.

This strategy requires that all the

transactions are carried out in both

systems, so a kind of

synchronization layer is required.

This layer serves as an abstraction

layer to the clients and performs all

the mapping and orchestration

required to keep both systems

synchronized. Ideally, it should

reside directly in the middleware

that links the clients to the servers,

as illustrated in Figure 6. In order to

increase the availability of the

system during the initial stages of

migration, the synchronization layer

may be designed to have the

option to succeed even if the

transaction fails in the new MES and

to report this error to the migration

team so that it can be addressed

before the migration is attempted

again. In a similar fashion, the

synchronization may be configured

to automatically switch off the

synchronization in the new MES if a

certain number of error occurs.

ERP

Other

Manufacturing

Applications

Figure 7 - Parallel Systems migration

strategy

Legacy Master


Legacy

MES

Other

Manufacturing

Applications

Equipment

Integration

Equipment

Integration

Equipment

Integration

New Master

Data GUI

New

MES

REPORTING /

ANALYSIS

DATABASES

ERP

Other

Manufacturing

Applications

10


Parallel Systems

It’s also worth mentioning that

because of the orchestration logic

of the synchronization layer, which

must call two systems, typically in a

serialized fashion for transaction

control, the clients will experience a

noticeable increase in the

transaction latency for the duration

of the migration.

Unlike the other approaches, in this

strategy data is duplicated in both

systems, so the ETL layer that brings

the data into the single-source-of-

truth (SSOT) must also have the

same switching logic as the

synchronization layer.

Both the Old MES and the New

MES will be active for the duration

of the migration as shown in Figure

7. At any time, the migration can be

rolled-back (suspended) and the

new MES can be turned off.

Other important remarks about the

Parallel Systems migration strategy:

• It’s not a requirement, but it’s

possible to freeze the master

data changes for the duration

of migration in order to avoid

master data synchronization

procedures.

• Out-of-sync systems detection

procedures must be in place.

• Migration target functionality is

the same functionality as the

old MES, which presents the

minimum common set of

functionality.

Synchronization Layer

As stated earlier in this document,

each migration case is unique.

The environment and context

conditions will determine the

appropriate migration path.

Nevertheless, it’s possible to

compare the different migration

strategies relative to each other.

That is precisely what is captured

in Table 3 which compares the

different strategies according to:

Risk, Migration Execution Time and

Cost (Effort).

Because the Phased Introduction

by MES Function can be covered

by either a partial Big Bang or by

a partial Phased Introduction by

Manufacturing Unit, the Phased

Introduction by MES Function is

not included in Table 3.

11

Table 3 - Migration strategies

comparison

Migration Strategies Comparison

BIG BANGPHASED INTRODUCTION

PARALLEL SYSTEMS

RISK

HIGH

Very difficult to test

in real production

Very difficult to

rollback

MEDIUM

Confidence is

increased over time

Somewhat easy to

rollback (phase by

phase)

LOW

Gives a lot of

confidence

Very easy to

rollback

MIGRATION

EXECUTION TIME

FASTEST

Basically, a switch-off

and switch-on

LONGEST

Each phase is a “small

migration”

MEDIUM

After enough

confidence is

gained, the switch

off – switch on can

take place

COST (EFFORT)

LOWEST $ ()

No need for

synchronization or

routing layers and

simpler migration

procedures – still

significant effort

involved

HIGH $$ ()

Requires routing layer

and requires complex

migration procedure –

effort is comparable

to Parallel Systems

HIGHEST $$$ ()

Requires

synchronization

layer (with

orchestration logic)

at application and

ETL routing layer –

effort is close to

Phased

Introduction

SUMMARY

The strategy with

highest risk, but the

shortest migration time

and lowest cost

A balanced migration

strategy

The strategy with the

lowest risk, but the

highest cost

TYPICAL

MIGRATION

SCENARIOS

Paper or Excel Based

MES

Stand Alone MES

Application

Integrated MES

Application, Low

Automation

Integrated MES

Application, High

Automation


Migration Planning

12

Regardless of the selected

migration strategy, there is a set of

steps that need to be carried out in

any case. This section includes a set

of activities that can be used as a

checklist for the migration plan and

it’s split among the following

phases:

• Migration Definition -

definition of migration scope,

target and strategy.

• Migration Preparation -

carrying out of activities to

enable migration.

• Migration Execution -

execution of the migration

strategy.

• Migration Closure - post-

migration close-down activities.

When multiple sites are

considered for migration, while

the ideal situation is to have a

target common landscape at the

end of the migration, it’s

important to bear in mind the

following:

• Each As-Is System Landscape is

different, and as such, the

migration procedure needs to

be tailored for each site. As

much as possible, what has

been developed for one site

should be re-used for the other

sites.

• The To-Be System Landscape

will most likely not be 100%

identical. This has to do on one

hand with the specifics of each

business, and on another one

with the different business

processes. A migration project

also provides an opportunity to

harmonize – when possible –

business processes in addition

to IT applications. At the end,

it’s the corporate decision,

what is the level of

harmonization that must be

achieved, balancing the need

for agility and flexibility from

the individual sites, and the

corporate need for cost

reductions by harmonizing the

systems landscape.

13

Migration Definition

Migration Planning

The Migration Definition phase is

the most important phase as it lays

the groundwork on which all

subsequent phases are based upon.

Table 4 captures the activities

associated with the Migration

Definition phase.

SEQUENCE ACTIVITY DESCRIPTION AND REMARKS

1

Capture As-Is

System

Landscape

This activity captures all the existing relevant manufacturing

applications, together with their responsibilities and inter-

dependencies.

For each site to be migrated, an As-Is System Landscape

needs to be captured.

2

Define the To-Be

System

Landscape

This activity defines which applications are replaced (partially

or totally) in the new landscape as well as the applications

that remain and the new applications that are added in the

system. It represents the desired end-system and it’s

independent of the migration strategy.

When undertaking a corporate harmonization project, this

activity has a special importance as it’s important to

understand and define what degree of harmonization is

desired; and if it’s possible to harmonize business processes

as well in addition to IT applications.

3

Migration

Strategy

Definition

This activity basically defines how the As-Is System Landscape

will be migrated to the To-Be System Landscape having in

mind, that it may take several steps to reach the end-state

goal. The strategy will basically be centered around one of the

migration strategies (Big Bang, Phased Introduction or

Parallel Systems) and it will contain:

A list of all the applications that need to be modified (with

the respective modifications)

A list of applications and utilities that need to be

developed to enable the migration (gateways,

synchronization/routing layers, data loaders, monitoring

procedures, etc.)

A list of tasks to be carried out during the migration

execution (backups, data loading, configuration file

changes, etc.)

Table 4 - Migration Definition activities

14

Migration Preparation

Migration Planning

This phase includes the execution

of all the necessary tasks required

to enable the migration execution.

A lot of the tasks have been

identified during the Migration

Strategy Definition activity of the

Migration Definition phase. Table 5

contains the typical set of activities

carried out during the Migration

Preparation phase – when the

sequence is the same it means that

the activities can be carried out in

parallel.

Table 5 - Migration Preparation activities


1 Systems Setup

This activity includes the hardware procurement, purchase (or

lease), installation & configuration for development, staging

and production environments for the new MES and any other

application required for migration.

1

New MES

Modeling &

Customization

This activity includes the configuration, modeling and

customization by the new MES.

1New MES

Training

This activity involves training for the different type of users:

System administrators

Power users

End users (can be delayed in time to be performed closer

to the migration execution)

1Application

Adaptation

This activity consists in adapting any existing application in

the As-Is Landscape at any level (presentation layer, business

layer, data layer) to accommodate the defined data migration

strategy.

1

Migration

Applications &

Utilities

Development

This activity consists in the development and testing of

migration specific applications and utilities necessary to

support the migration strategy, which typically includes:

Routing layers

Synchronization layers

Gateways and bridge applications

Data loading & synchronization procedures for both

master data and runtime data

Monitoring procedures

Rollback procedures

2

Integrated

Testing &

Validation

This activity consists of integrated tests for the adapted

applications together with any migration utilities which have

been developed. The goal is to make both functional and

non-functional criteria of the complete system.

3Migration

Rehearsal

This activity is used to validate the migration procedure as

well as to get the team familiar with the migration procedure

– including:

Execution of the migration steps in the right sequence

(including backups, data loading, configuration file

changes)

Getting validation that the migration steps have been

completed successfully

Getting enough information to decide whether to proceed

or to abort and rollback the migration (go/no-go decision)

Monitoring the system after migration with monitoring

procedures and validation checkpoints and deciding on

what to do if validation procedures fail

Implement a support process to respond to problems

This activity is also used to measure the time required for the

different migration procedures to complete.

15

Migration Execution

Migration Planning

This phase includes the execution

of all the activities to carry out the

real live migration. It assumes that

the necessary downtime has been

agreed with production. Table 6

captures the activities of this phase

with some of them depending on

the type of migration strategy.

Table 6 - Migration Execution activities


1Roll-Out & Go-

Live

This activity consists in carrying out all the steps in the

defined sequence as validated during the migration

rehearsals. There’s typically a downtime period involved with

this activity and at the end of the activity, the system must be

live so that it can be used for normal operations.

2Monitoring &

Babysitting

This activity is used to monitor closely the system as the

probability of an error occurring is very high given the

amount of changes applied to the system. The monitoring

procedures must also be followed up closely and IT personnel

must be on standby to quickly respond to problems. It may

come to the point where the migration needs to be rolled

back.

3Phase-In /

Phase-Out

For the Phased Introduction migration strategy, this activity

involves the phase-in of new manufacturing processes into

the new MES system and phase-out from the old MES system.

3 Switch-Off

For the Parallel Systems migration strategy, this activity

represents the switch off of the old MES and it is performed

after enough confidence has been built into the new MES.

4

Retirement Of

Migration

Applications &

Utilities

This activity involves the shutdown and removal of

middleware, routing and synchronization layers, gateways,

bridges, monitoring and validation software which was

developed and introduced for the single purpose of

supporting the migration. This activity needs to be well

controlled as it carries a high degree or risk.

16

Migration Closure

Migration Planning

The Migration Closure phase

consists of all the activities

necessary to properly close-down

the migration project as captured

in Table 7. It may (or may not)

include activities to activate new

functionality from the new MES

system. Note that typical project

management activities (such as

Lessons Learned and Project

Close-Down Meeting) are not

covered in this section.

Table 7 - Migration Closure activities


1Archive Data

From Old MES

In this activity, any relevant data from the old MES system is

archived so that it’s available when and if required. Special

care needs to be taken to ensure that the data is accessible

for the timeframe it’s required. For long term data archiving,

the usage of .TXT, .CSV, .XML for text or .TIFF for images is

recommended.

1Activate New

MES Functionality

Because most the MES migrations target a one-to-one

replacement, after the MES migration is complete, if desired,

new functionality can be activated.

2

Decommissioning

Of Unnecessary

Hardware and

Software

Unused hardware and software may be re-used for other

purposes, sold, returned (if leased/borrowed) or simply

disposed. This applies not only to hardware and software

related with the old MES, but also to any application or utility

that was required by the migration.

Critical Manufacturing provides manufacturers in highly-complex environments with a modular, scalable manufacturing execution and intelligence system that enables users to flexibly address market demands, increase efficiency and bolster reliability across the supply

chain while lowering TCO. The company is part of the Critical Group, a private group of companies founded in 1998 to provide solutions for mission and business critical information systems.

www.criticalmanufacturing.com

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Austin, TXt: +1-512 291 0068

Dresden, Germanyt: +49 (0)351 4188 0639

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About Critical Manufacturing

17

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