Filed by: ON Semiconductor Corporation

Pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

of the Securities Exchange Act of 1934

Subject Company: AMIS Holdings, Inc.

Commission File No.: 000-50397

This filing contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, statements related to the benefits of the proposed transaction between ON Semiconductor Corporation (“ON”) and AMIS Holdings, Inc. (“AMIS”) and the future financial performance of ON. These forward-looking statements are based on information available to ON and AMIS as of the date of this release and current expectations, forecasts and assumptions and involve a number of risks and uncertainties that could cause actual results to differ materially from those anticipated by these forward-looking statements. Such risks and uncertainties include a variety of factors, some of which are beyond ON’s or AMIS’ control. In particular, such risks and uncertainties include difficulties encountered in integrating merged businesses; the risk that the transaction does not close, including the risk that the requisite stockholder and regulatory approvals may not be obtained; the variable demand and the aggressive pricing environment for semiconductor products; dependence on each company’s ability to successfully manufacture in increasing volumes on a cost-effective basis and with acceptable quality its current products; the adverse impact of competitive product announcements; revenues and operating performance, changes in overall economic conditions, the cyclical nature of the semiconductor industry, changes in demand for our products, changes in inventories at customers and distributors, technological and product development risks, availability of raw materials, competitors’ actions, pricing and gross margin pressures, loss of key customers, order cancellations or reduced bookings, changes in manufacturing yields, control of costs and expenses, significant litigation, risks associated with acquisitions and dispositions, risks associated with leverage and restrictive covenants in debt agreements, risks associated with international operations, the threat or occurrence of international armed conflict and terrorist activities both in the United States and internationally, risks and costs associated with increased and new regulation of corporate governance and disclosure standards (including pursuant to Section 404 of the Sarbanes-Oxley Act of 2002), and risks involving environmental or other governmental regulation. Information concerning additional factors that could cause results to differ materially from those projected in the forward-looking statements is contained in ON’s Annual Report on Form 10-K as filed with the Securities and Exchange Commission (the “SEC”) on February 23, 2007, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other of ON’s SEC filings, and AMIS’ Annual Report on Form 10-K as filed with the SEC on February 28, 2007, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other of AMIS’ SEC filings. These forward-looking statements should not be relied upon as representing ON’s or AMIS’ views as of any subsequent date and neither undertake any obligation to update forward-looking statements to reflect events or circumstances after the date they were made.

This communication is being made in respect of the proposed transaction involving ON and AMIS. In connection with the proposed transaction, ON plans to file with the SEC a Registration Statement on Form S-4 containing a Joint Proxy Statement/Prospectus and each of ON and AMIS plan to file with the SEC other documents regarding the proposed transaction. The definitive Joint Proxy Statement/Prospectus will be mailed to stockholders of ON and AMIS. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

Investors and security holders will be able to obtain free copies of the Registration Statement and the Joint Proxy Statement/Prospectus (when available) and other documents filed with the SEC by ON and AMIS through the web site maintained by the SEC at www.sec.gov. In addition, investors and security holders will be able to obtain free copies of the Registration Statement and the Joint Proxy Statement/Prospectus (when available) and other documents filed with the SEC from ON by directing a request to ON Semiconductor Corporation, 5005 East McDowell Road, Phoenix, AZ, 85008, Attention: Investor Relations (telephone: (602) 244-3437) or going to ON’s corporate website at www.onsemi.com, or from AMIS by directing a request to AMIS Holdings, Inc., 2300 Buckskin Road Pocatello, ID, 83201, Attention: Investor Relations (telephone: (208) 233-4690) or going to AMIS’ corporate website at www.amis.com.

ON and AMIS, and their respective directors and executive officers, may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information regarding ON’s directors and executive officers is contained in its annual proxy statement filed with the SEC on April 11, 2007. Information regarding AMIS’ directors and executive officers is contained in AMIS’ annual proxy statement filed with the SEC on May 24, 2007. Additional information regarding the interests of such potential participants will be included in the Joint Proxy Statement/Prospectus and the other relevant documents filed with the SEC (when available).

Filed below is a presentation to ON investors on December 13, 2007 regarding ON’s proposed acquisition of AMIS.

The Power of

ON Semiconductor

Investor Presentation

December 2007

2

Safe Harbor Statement & Non-GAAP Financial

Measure Information

During the course of this presentation, ON Semiconductor may make projections or

other forward-looking statements regarding future events or its future financial

performance.  The words “estimate,”

“intend,”

“expect,”

“plan,”

or similar expressions are

intended to identify forward-looking statements.  ON Semiconductor wishes to caution

that

such

statements

are

subject

to

risks

and

uncertainties

that

could

cause

actual

events

or results to differ materially.  Important factors relating to our business, including factors

that could cause actual results to differ from our forward-looking statements, are

described in our Form 10-K and other filings with the SEC.  ON Semiconductor assumes

no obligation to update forward-looking statements to reflect actual results or changed

assumptions or other factors.

Some data in this presentation may include non-GAAP financial measures.  You can

find reconciliations of certain of these non-GAAP financial measures to the most directly

comparable measures under generally accepted accounting principles within the

following

presentation

at

our

website

(http://www.onsemi.com)

at

the

“Investors”

section

under the category “Annual Reports/Financial Releases.”

3

This document contains forward-looking statements within the meaning of the Private Securities Litigation Reform

Act of 1995. These forward-looking statements include, but are not limited to, statements related to the benefits of the

proposed transaction between ON Semiconductor Corporation (“ON”) and AMIS Holdings, Inc. (“AMIS”) and the future

financial performance of ON. These forward-looking statements are based on information available to ON and AMIS as

of the date of this release and current expectations, forecasts and assumptions and involve a number of risks and

uncertainties that could cause actual results to differ materially from those anticipated by these forward-looking

statements.

Such

risks

and

uncertainties

include

a

variety

of

factors,

some

of

which

are

beyond

ON’s

or

AMIS’

control.

In

particular,

such

risks

and

uncertainties

include

difficulties

encountered

in

integrating

merged

businesses;

the

risk

that

the transaction does not close, including the risk that the requisite stockholder and regulatory approvals may not be

obtained; the variable demand and the aggressive pricing environment for semiconductor products; dependence on

each

company’s

ability

to

successfully

manufacture

in

increasing

volumes

on

a

cost-effective

basis

and

with

acceptable

quality its current products; the adverse impact of competitive product announcements; revenues and operating

performance, changes in overall economic conditions, the cyclical nature of the semiconductor industry, changes in

demand

for

our

products,

changes

in

inventories

at

customers

and

distributors,

technological

and

product

development

risks, availability of raw materials, competitors' actions, pricing and gross margin pressures, loss of key customers,

order cancellations or reduced bookings, changes in manufacturing yields, control of costs and expenses, significant

litigation, risks associated with acquisitions and dispositions,

risks associated with leverage and restrictive covenants in

debt agreements, risks associated with international operations,

the threat or occurrence of international armed conflict

and terrorist activities both in the United States and internationally, risks and costs associated with increased and new

regulation of corporate governance and disclosure standards (including pursuant to Section 404 of the Sarbanes-Oxley

Act of 2002), and risks involving environmental or other governmental regulation.  Information concerning additional

factors

that

could

cause

results

to

differ

materially

from

those

projected

in

the

forward-looking

statements

is

contained

in ON’s Annual Report on Form 10-K as filed with the Securities and Exchange Commission (the “SEC”) on February

23, 2007, Quarterly Reports on Form 10-Q Current Reports on Form 8-K and other of ON’s SEC filings, and AMIS’

Annual Report on Form 10-K as filed with the SEC on February 28, 2007, Quarterly Reports on Form 10-Q, Current

Reports

on

Form

8-K

and

other

of

AMIS’

SEC

filings.

These

forward-looking

statements

should

not

be

relied

upon

as

representing ON’s or AMIS’

views as of any subsequent date and neither undertake any obligation to update forward-

looking statements to reflect events or circumstances after the date they were made.

4

This communication is being made in respect of the proposed transaction involving ON and AMIS. In

connection with the proposed transaction, ON plans to file with the SEC a Registration Statement on Form S-4

containing

a

Joint

Proxy

Statement/Prospectus

and

each

of

ON

and

AMIS

plan

to

file

with

the

SEC

other

documents

regarding the proposed transaction. The definitive Joint Proxy Statement/ Prospectus will be mailed to stockholders of

ON and AMIS. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE JOINT PROXY

STATEMENT/PROSPECTUS AND OTHER DOCUMENTS FILED WITH THE SEC CAREFULLY IN THEIR ENTIRETY

WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE

PROPOSED TRANSACTION.

Investors and security holders will be able to obtain free copies of the Registration Statement and the Joint

Proxy Statement/Prospectus (when available) and other documents filed with the SEC by ON and AMIS through the

web site maintained by the SEC at www.sec.gov. In addition, investors and security holders will be able to obtain free

copies of the Registration Statement and the Joint Proxy Statement/Prospectus (when available) and other documents

filed with the SEC from ON by directing a request to ON Semiconductor Corporation, 5005 East McDowell Road,

Phoenix,

AZ,

85008,

Attention:

Investor

Relations

(telephone:

(602)

244-3437)

or

going

to

ON’s

corporate

website

at

www.onsemi.com, or from AMIS by directing a request to AMIS Holdings, Inc., 2300 Buckskin Road Pocatello, ID,

83201,

Attention:

Investor

Relations

(telephone:

208-233-4690)

or

going

to

AMIS’

corporate

website

at

www.amis.com.

ON and AMIS, and their respective directors and executive officers, may be deemed to be participants in the

solicitation of proxies in respect of the proposed transaction. Information regarding ON’s directors and executive officers

is

contained

in

its

annual

proxy

statement

filed

with

the

SEC

on

April

11,

2007.

Information

regarding

AMIS’

directors

and

executive

officers

is

contained

in

AMIS’

annual

proxy

statement

filed

with

the

SEC

on

May

24,

2007.

Additional

information regarding the interests of such potential participants will be included in the Joint Proxy

Statement/Prospectus

and

the

other

relevant

documents

filed

with

the

SEC

(when available).

5

A Winning Combination

Over 90 Years of Semiconductor Expertise

•

World class, high

volume, cost

effective products

•

Leading standard

products in

Automotive,

Computing,

Consumer and

Communications

end markets

•

Industry leader in

power management

LTM Revenue:

$1,560MM

LTM EBITDA:

$388MM

LTM Free Cash Flow

(1)

:       $223MM

•

Leader in analog

and mixed signal

technology and

design

•

Automotive products

leader

•

Leading custom

products in Medical,

Mil/Aero and

Industrial end

markets

•

8-10 years average

product lifespan

LTM Revenue:

$619MM

LTM EBITDA:

$134MM

LTM Free Cash Flow

(1)

:

$25MM

(1)     Free cash flow defined as operating cash flow less capital expenditures.

•

Manufacturing

synergies

•

Operating expense

savings

•

Tax savings

•

Capital expenditure

reductions

Synergies

6

Transaction Overview

Terms

Each share of AMIS will be exchanged for 1.150 ON shares

Consideration

Stock-for-stock transaction valued at approximately $915 million

Pro Forma

Ownership

74% ON shareholders, 26% AMI shareholders

Board of Directors

Expanded to 8 Members with the addition of Christine King, AMIS CEO

Share Repurchase

Board authorized an additional 20MM share increase to ON’s existing

stock repurchase program.  Total of 50MM shares available, approximately

50% of the shares to be issued in this transaction

Anticipated Close

First half of 2008

Conditions

Approval by ON and AMIS shareholders, customary closing conditions

and regulatory approvals. 

Voting Agreements

Stockholders holding approximately 24% of the voting stock of AMIS and

the executive officers of both companies have entered into voting

agreements in support of the transaction

7

Transaction Rationale

Accelerates ON’s

Analog

Transformation

•

Expands mixed signal design and product capability

•

Over

88%

of

AMI’s

custom

products

/

design

wins

are

sole

sourced

•

Higher margin product portfolio with products that have long product

cycles

•

Pro Forma LTM gross margins of 40%

Strengthen End

Market Presence and

Gain Entry into

New Markets

•

Expands presence in automotive, consumer, communications and

industrial end markets

•

Gain entry into high growth, higher margin medical market and high-

margin Mil/Aero market

•

Increase value proposition to end customers with both leading standard

and custom products

Leverage ON’s

Operational

Excellence to Drive

Cost Savings

•

Successful

track

record

of

cost

reduction

and

rationalization

to

improve

profitability of combined business

•

Utilize advanced sub-micron Gresham fabrication facility to drive cost

savings and extend product roadmap

•

Consolidate combined company’s manufacturing network

Significant Scale

and Cash Flow

Generation

•

Pro Forma LTM revenues of $2.2 billion*

•

Pro Forma LTM EBITDA of $522 million* (with zero synergies)

•

Pro Forma LTM free cash flow of $248 million*

•

Potential to accelerate revenue growth of combined companies

•

Accretive to earnings per share exiting 2008*

•Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor.

Free

cash

flow

defined

as operating cash flow less capital expenditures. Earnings per share excludes amortization of  intangibles

8

Standard

12%

Custom

88%

Standard /

Discrete

49%

Custom /

Integrated

Circuits

51%

LTM Revenue

$1,560MM

/

LTM Revenue

$619MM

LTM Revenue*

$2,179MM

Note:  Charts do not include revenue from manufacturing services.

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor.

Diversified Product Platform

Discrete

65%

Integrated

Circuits

35%

A Leader in Mixed Signal & Analog Technologies

9

Automotive

27%

Mil. / Aero

8%

Medical

17%

Communications

8%

Industrial

25%

Computing

9%

Consumer

6%

Computing

23%

Industrial

13%

Wireless

19%

Networking

7%

Automotive

17%

Consumer

21%

/

Note: Not all segments included.

Charts do not include revenue from manufacturing services.

Balanced End Market Presence

Computing

19%

Industrial

17%

Communications

20%

Mil. / Aero

2%

Consumer

17%

Automotive

20%

Medical

5%

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

On

Semiconductor

and

AMI

Semiconductor.

LTM Revenue

$1,560MM

LTM Revenue

$619MM

LTM Revenue*

$2,179MM

10

ON Market Segments

Automotive and

Power Regulation

Computing Products

Digital and

Consumer Products

Standard Products

AC-DC / DC-DC converters

Linear regulators

PWM controllers                        

LDO                                        

VCore

Controllers

Gate Drivers                        

DDR Memory Controllers

Low / Medium Voltage

MOSFETS

Filters / Protection

Audio Amps                           

DC-DC converters

Analog switches

LED drivers

ESD protection                             

ECL Clocks

Small signal transistors

Standard logic ICs

Small signal diodes

$427

$349

$174

$500

Revenue:

Revenue:

Revenue:

Revenue:

Note: Product Revenues represent last twelve months ending September 2007.

11

AMI Market Segments

Automotive

Industrial

Medical

Communications

Military and Aerospace

Revenue: $169M

Revenue: $157M

Revenue: $104M

Revenue: $48M

Revenue: $48M

In-Vehicle Sensors

Stability Control

Engine Management

Drive by Wire

Headlight Control

Factory Automation

Industrial Networking

Wireless Security

Energy Metering

Medical Imaging

Audiology

Implantable Devices

Diagnostic Therapy

Power over Ethernet

Wireless Base Stations

Switches & Routers 

Optical Networking

Cockpit Displays

Guidance Systems

Infrared Imaging

Applications:

Applications:

Applications:

Applications:

Applications:

Note: Revenues represent last twelve months ending September 2007.

12

Pro Forma Combined Revenue:

$410MM

(2)

Bolster

Existing

End

Markets

-

Automotive

Applications

Applications

Communications

Electromagnetic Mirrors

and Glass

Infotainment

Instrumentation

Stability & Suspension

Lighting

Collision Avoidance

Engine Control

USB

Electronic Transmission

Antilock Braking

Safety Airbag

Traction Control

Security

Active Noise

Cancellation

Multi-zone Climate

Control

Auto Toll Payment

Compass

LED Brake Lights

Backup Sensor

Power Window Sensor

Angular Acceleration

Sensors

Seat Position & Seat

Heating

Steering Wheel Sensors

Transmission Control &

Gearbox Position Sense

Brake Pressure

Tire Pressure Monitor

Engine Control

Headlights

Smart Fusebox

Rain Sensor

Dashboard Electronics

Keyless Entry

Customers

Revenue: $241MM

(1)

(1)

(1)

Revenue: $169MM

(1)

(1)

(1)

(1) Revenues represent last twelve months ending September 2007.

(2) Represents combined financials as reported for the last twelve months ending September 2007 for ON Semiconductor and AMI Semiconductor.

Customers

13

Customers

Customers

Applications

Military Radios / Battlefield

Communications

Cockpit Displays

Guidance Systems

Munitions / Missile Systems

Night Vision

Applications

•

LTM Revenues of $104MM

(1)

•

~70 Customers Including Top 7 Medical Companies

•

Leadership Position with 10% Market Share

(2)

•

LTM

revenues

of

$48MM

(1)

•

Ranked

#3

with

8%

Market

Share

(3)

New Market Opportunities

(2) Based on Company estimates and Gartner data for 2006.

(3) Based on Gartner data for 2006 Military / Aerospace ASIC market share.

Military / Aerospace

Medical

Hearing Aids

Neurological Stimulus

Management

Cardiovascular Management /

Pacemakers

Body Temperature Sensing

Blood Glucose Monitoring

CT Scan

Ultrasound

Portable X-ray

Pulse Oximeters

Blood Oxygen/Chemistry

Monitoring

(1) Revenues represent last twelve months as of September 29, 2007.

Implantable Defibrillators

External Portable

Defibrillators

Cochlear Implants

ECG Monitoring

14

Broad and Deep Customer Relationships

15

Leverage ON’s Operational Excellence

Highlights:

•

Semiconductor International named “Top Fab of 2002”

•

Quality Magazine named “Quality Plant of the Year 2005

Honoree”

•

Mil/Aero

certifications

&

NSA

“Trusted

Fab

Status”

(Q4’05)

•

Best-in-Class Prototype & Production Cycle Times

•

Hi-Tech Yield & Failure Analysis Equipment & Systems

•

Future Technology potential with 90nm/65nm capable

Research & Development tool set

Gresham Fabrication Facility

Achieve Operational Synergies

Extend AMI’s

High Voltage and Low Power Offerings

Accelerate Margin Growth

16

Leshan, China

Aizu, Japan

Gresham, OR

Phoenix, AZ

Roznov, Czech Republic

Pietsany, Slovakia

Seremban, Malaysia

(Site 1 & 2)

Carmona, Philippines

Oudenaarde, Belgium

Pocatello, Idaho

Key Locations

Global Manufacturing Infrastructure

Back-end Facilities:

•

Leshan, China

•

Seremban, Malaysia (Site-1)

•

Carmona, Philippines

Wafer Facilities:

•

Roznov, Czech Republic

Front-end Facilities:

•

Phoenix, Arizona

•

Gresham, Oregon

•

Aizu, Japan

•

Pietany, Slovakia

•

Seremban, Malaysia (Site-2)

•

Roznov, Czech Republic

Legend

Front-end Facilities:

•

Pocatello, Idaho

•

Oudenaarde, Belgium

Back-end Facilities:

•

Calamba, Philippines

Calamba, Philippines

17

Financial Overview

ON

(1,2)

AMIS

(1,2)

Combined

(3)

Last Twelve Months

$522

$134

$388

EBITDA

Employees

Operating Margin

Gross Margin

Revenue

14,675

2,984

11,691

17.4%

13.6%

18.9%

40.0%

44.5%

38.2%

$2,179

$619

$1,560

($MM)

•

Large revenue base with over $2 billion in LTM revenue

•

Strong combined gross and operating margins

•

Significant cash flow generation

(1) Revenues represent last twelve months ending September 2007 for ON Semiconductor and AMI Semiconductor.

(2) Non-GAAP Operating Margin excludes amortization of acquisition and related intangibles and restructuring and impairment charges.

(3) Represents combined financials as reported for the last twelve months ending September 2007 for ON Semiconductor and AMI Semiconductor.

18

Significant Revenue Scale

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor.

** As of 12/31/2006.

/

*

($ in millions)

Combined Company Generates Economies of Scale and

Improved Financial Performance

**

$2,739

$2,546

$2,362

$2,179

$1,857

$1,657

$1,560

$1,316

$1,072

$725

$9,741

$10,923

$13,742

19

Generating Substantial EBITDA

(Excludes Synergies)

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor.

** As of 12/31/2006.

/

*

($ in millions)

Note: Excludes one time items.

**

$2,116

$1,352

$761

$615

$565

$522

$458

$388

$273

$234

$177

$4,435

20

And Significant Free Cash Flow

Free Cash Flow Yield (FCF/ Market Capitalization):

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor

divided

by

the

combined market capitalization.

** Represents

annualized

combined

financials

as

reported

for

the

last

three

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor

divided

by

the combined market capitalization.

*** As of 12/31/2006.

/

*

Market capitalization as of December 12, 2007

***

/

**

(3Q annualized)

8.9%

8.7%

8.4%

7.8%

7.5%

7.0%

6.5%

6.3%

6.3%

6.2%

3.4%

1.7%

NM

21

Transaction Rationale

Accelerates ON’s

Analog

Transformation

•

Expands mixed signal design and product capability

•

Over 88% of AMI’s

custom products / design wins are sole sourced

•

Higher margin product portfolio with products that have long product

cycles

•

Pro Forma LTM gross margins of 40%

Strengthen End

Market Presence and

Gain Entry into

New Markets

•

Expands presence in automotive, consumer, communications and

industrial end markets

•

Gain entry into high growth, higher margin medical market and high-

margin Mil/Aero market

•

Increase value proposition to end customers with both leading standard

and custom products

Leverage ON’s

Operational

Excellence to Drive

Cost Savings

•

Successful

track

record

of

cost

reduction

and

rationalization

to

improve

profitability of combined business

•

Utilize advanced sub-micron Gresham fabrication facility to drive cost

savings and extend product roadmap

•

Consolidate combined company’s manufacturing network

Significant Scale

and Cash Flow

Generation

•

Pro Forma LTM revenues of $2.2 billion*

•

Pro Forma LTM EBITDA of $522 million* (with zero synergies)

•

Pro Forma LTM free cash flow of $248 million*

•

Potential to accelerate revenue growth of combined companies

•

Accretive to earnings per share exiting 2008*

* Represents

combined

financials

as

reported

for

the

last

twelve

months

ending

September

2007

for

ON

Semiconductor

and

AMI

Semiconductor.

Free

cash

flow

defined

as

operating

cash

flow

less

capital

expenditures.

Earnings

per

share

excludes

amortization

of

intangibles