This document provides an investor presentation for Ultra Clean Holdings, Inc. for Fall 2017. Some key points: - Q3 2017 saw record revenue of $243 million, a 6.3% increase over Q2 2017, driven by growth in the semiconductor market. Non-GAAP diluted EPS was $0.62. - Guidance for Q4 2017 is for revenue of $240-250 million and non-GAAP EPS of $0.57-0.63. - The semiconductor market is expected to grow through 2017 due to increasing spending on memory technologies like 3D NAND and logic nodes. Ultra Clean is well positioned in the fast growing deposition and etch segments. -

1. Fall 2017
Investor Presentation

2. Safe Harbor
This presentation contains, or may be deemed to contain, "forward-looking statements" (as defined in the US Private Securities Litigation
Reform Act of 1995) which reflect our current views with respect to future events and financial performance. We use words such as
"anticipates,", “projection”, “outlook”, “forecast”, "believes," "plan," "expect," "future,"' "intends," "may," "will," "estimates," "predicts,"
and similar expressions to identify these forward-looking statements. Forward looking statements included in this presentation include our
expectations about achieving our longer-term revenue and profitability goals and with respect to our fourth quarter 2017 outlook. All
forward-looking statements address matters that involve risks and uncertainties. Accordingly, the Company’s actual results may differ
materially from the results predicted or implied by these forward-looking statements. These risks, uncertainties and other factors also
include, among others, those identified in "Risk Factors”, "Management's Discussion and Analysis of Financial Condition and Results of
Operations'' and elsewhere in our annual report on Form 10-K for the year ended December 30, 2016 as filed with the Securities and
Exchange Commission and subsequently filed quarterly reports on Form 10-Q. Ultra Clean Holdings, Inc. undertakes no obligation to
publicly update or review any forward-looking statements, whether as a result of new information, future developments or otherwise
unless required by law.
Management uses non-GAAP net income and non-GAAP net income per diluted share to evaluate the Company's operating and financial
results. The Company believes the presentation of non-GAAP results is useful to investors for analyzing our core business and business
trends and comparing performance to prior periods, along with enhancing investors' ability to view the Company's results from
management's perspective. The presentation of this additional information should not be considered a substitute for results prepared in
accordance with GAAP. Tables presenting reconciliations of non-GAAP results to U.S. GAAP results are included in the Appendix.
2
Non-GAAP

3. 3
UCT Highlights
* Non-GAAP reconciliation in the Appendix
Q3 2017 delivered record revenue and solid profitability
• Q3’17 revenue of $243M
– 6.3% increase quarter-over-quarter
– 66.0% increase year-over-year
– Semiconductor up 5.7% quarter-over-quarter
• Q3’17 GAAP diluted EPS of $0.57 and
non-GAAP* diluted EPS of $0.62
• Q4’17 guidance of $240-250M
GAAP EPS of $0.54-0.60
non-GAAP EPS of $0.57-0.63
$0
$100
$200
$300
Q3'16 Q4'16 Q1'17 Q2'17 Q3'17
$146
$175
$205
$228
$243
6.1%
8.8%
10.3%
11.2%
10.1%
16.1%
17.4%
18.3% 19.0% 17.6%
Revenue
(in M)
Gross
Margin
Non-GAAP
Operating
Margin*

4. 4 Main Drivers for 2017
– 2017 WFE spending to increase on 3D NAND & node transitions in 10nm Logic & 1x DRAM
– Our primary customers are concentrated in Deposition & Etch; fastest growing areas of WFE
– High OEM factory capacity utilization driving strong push for expanded outsourcing
• Share gain opportunities for the strongest suppliers with the broadest capabilities
• Ability to manufacture major modules across a customer’s entire tool is fueling strong growth
– Ability to meet shortfalls in capacity across the supply base, filling additional demand
4
UCT Drivers
Leading outsourcing manufacturer
for the semiconductor capital equipment industry

5. 2015
2016
2017(F)
2018(F)
$31.9
$35.6
$44.8 $44.9
5
WaferFabEquipmentSpendingReachingNewHighs
($B)
26%
Source: Gartner October 2017

6. Deposition & Etch Outperforming WFE Market
2017 WFE Estimate: $45B
>80%
of UCT Semi
Sales
Dep & Etch
CapEx Spend
15-17% CAGR
2015 - 2018
Total CapEx
Spend
~12% CAGR
2015 - 2018
Thermal
& Implant
6%
Deposition
24%
Removal
33%
Lithography
21%
Metrology &
Inspection
12%
Other
4%
Source: Gartner October 2017, SEMI WSEMS and UCT estimates6

7. OEM Component
Suppliers
34%
OEM Integration
In-Sourcing
44%
UCT
5%
For example: Flex, Celestica,
Benchmark, etc.
Specialty Contract
Manufacturers
7
Inflection:OEM Outsourcing Accelerating Dramatically
Source: UCT estimates as of Feb 2017.

8. 8
Winning Strategy
Primary Focus on Semiconductors
Broaden Critical
Process Capabilities
Make Strategic
Investments
Increase UCT
Content on
Platforms
Deepen Engagement
with Existing Customers
& Add New Customers

9. GAS
FOUNDING
CAPABILITY
9
Expanding Critical Capabilities to Capture New Opportunities
Chemical Delivery Sub-Systems
Complete Assemblies
LIQUID
DELIVERY
ASSEMBLY
INTEGRATION
& TEST
Manufactured
Components
FRAMES PROTOTYPE
MACHINING
MACHINING
METALS
PLASTIC
MODULES
SHEET METAL
FORMING
THERMAL
PRODUCTS

10. 10
UCT Expert Outsourcing Partner
MANUFACTURING
INTEGRATION & TEST
PROTOTYPING/
DEVELOPMENT
MANUFACTURING
ENGINEERING
SUPPLY CHAIN MANAGEMENT
▪ Design for manufacturability (DFM)
▪ Partnering with customers for new product requirements
▪ Network of global, strategic suppliers
▪ Comprehensive new product introduction process
▪ Sub-system through full tool integration

11. 11
Now Addressing Major Modules in Semiconductor Equipment
Wafer transfer: 10 – 20% 15 – 30%
Factory Interface
Vacuum Transfer
Process Chamber: 55 – 70% 50 – 75%
Gas Panel: 15 – 20% 0 – 10%
TYPICAL CVD & ETCH TOOL COST
OTHER PROCESS
TOOL TYPES
Source: UCT estimates.

12. 12
UCT Strong Growth in Semiconductor Equipment
Strategy to focus on semiconductor
successful
• Q3 2017 Semi revenue increased 5.7% q/q
– Higher WFE spend driven by complex technologies
– Positioned as leading outsourced manufacture for OEMs
• Q3 2017 Semi revenue 91.7% of total
• Keeping pace with customers’ demand for
increased content and higher functionality
Non-semi dominated by Display
• Adoption of OLED continues at historic levels
• OLED and build-out of Gen 10.5
• Growth at 2 to 4 times our historical rate
2012
2013
2014
2015
2016
$345
$390
$423 $433
$508
(in $M)

13. ($ in millions except EPS) Q3’16 Q4’16 Q1’17 Q2’17 Q3’17
Revenue $146.2 $174.5 $204.6 $228.3 $242.6
Gross Margin 16.1% 17.0% 18.3% 19.0% 17.6%
GAAP Net Income (loss) $2.6 $10.0 $14.3 $20.2 $19.7
GAAP Diluted EPS $0.08 $0.30 $0.42 $0.59 $0.57
Non-GAAP* Operating Margin 6.1% 8.8% 10.3% 11.2% 10.1%
Non-GAAP* Net Income (loss) $5.7 $12.0 $15.9 $21.3 $21.3
Non-GAAP* Diluted EPS $0.17 $0.36 $0.47 $0.62 $0.62
Cash $47.3 $52.5 $54.9 $59.5 $65.9
13
Select Financial Data
* Non-GAAP results exclude intangible asset amortization and non-recurring expense items

14. • Outperforming a growing Semiconductor WFE market
• Rapidly expanding opportunities in customers’ major modules
• Delivering what customers need (OTD, quality, cost)
• Industry trends reinforce leading position as a supply chain
consolidator
• Key partner to top customers
14
Compelling UCT Opportunity
Winning
Strategy
Strong
Margins
Improved
Profitability
Solid Cash
Generation

15. Thank You

16. (in thousands) Q3’16 Q4’16 Q1’17 Q2’17 Q3’17
Reported net income (loss) on a GAAP basis $2,614 $9,953 $14,341 $20,179 $19,716
Amortization of intangible assets (1) $1,438 $1,439 $1,231 $1,231 $1,231
Executive transition costs (2) $925 - - - -
Restructuring charges (3) $(105) $109 - - -
Impairment of “Held for Sale” Assets (4) - $666 - - -
Termination of Contractual Obligation (5) - $438 - - -
Income tax effect of non-GAAP adjustments (6) $(574) $(549) $(256) $(163) $(159)
Income tax effect of valuation allowance (7) $1,391 $(49) $576 $18 $524
Non-GAAP net income (loss) $5,689 $12,007 $15,892 $21,265 $21,312
16
Reconciliation: GAAP Net Income to Non-GAAP Net Income
(1) Amortization of intangible assets related to the Company's acquisitions of AIT, Marchi and Miconex
(2) Represents expense for termination benefits paid to former executives of the Company
(3) Adjustment to previous restructuring reserve related to the abandonment of one of the Company's facilities
(4) Impairment of assets classified as “held for sale” related to our 3D printing business in Singapore
(5) Amount paid related to the termination of a long-term contractual obligation to our 3D printing business in Singapore
(6) Tax effect on amortization of intangible assets, executive transition costs, restructuring charges, acquisition costs, impairment charges, and buy-out costs based on the non-GAAP tax rate
(7) The Company's GAAP tax expense is generally higher than the Company's non-GAAP tax expense, primarily due to losses in the U.S. with full federal and state valuation allowances. The Company's non-
GAAP tax rate and resulting non-GAAP tax expense considers the tax implications as if there was no federal or state valuation allowance position in effect

17. (in thousands) Q3’16 Q4’16 Q1’17 Q2’17 Q3’17
Reported income (loss) from operations on a GAAP basis $6,700 $12,670 $19,773 $24,405 $23,262
Amortization of intangible assets (1) $1,438 $1,439 $1,231 $1,231 $1,231
Executive transition costs (2) $925 - - - -
Restructuring charges (3) $(105) $109 - - -
Impairment of “Held for Sale” Assets (4) - $666 - - -
Termination of Contractual Obligation (5) - $438 - - -
Non-GAAP income from operations $8,958 $15,322 $21,004 $25,636 $24,493
17
Reconciliation: GAAP Income from Operations to Non-GAAP
Income from Operations
(1) Amortization of intangible assets related to the Company's acquisitions of AIT, Marchi and Miconex
(2) Represents expense for termination benefits paid to former executives of the Company
(3) Adjustment to previous restructuring reserve related to the abandonment of one of the Company's facilities
(4) Impairment of assets classified as “held for sale” related to our 3D printing business in Singapore
(5) Amount paid related to the termination of a long-term contractual obligation to our 3D printing business in Singapore

18. Q3’16 Q4’16 Q1’17 Q2’17 Q3’17
Reported net income (loss) on a GAAP basis $0.08 $0.30 $0.42 $0.59 $0.57
Amortization of intangible assets (1) $0.04 $0.04 $0.04 $0.04 $0.04
Executive transition costs (2) $0.03 - - - -
Restructuring charges (3) $0.00 - - - -
Impairment of “Held for Sale” Assets (4) - $0.02 - - -
Termination of Contractual Obligation (5) - $0.01 - - -
Income tax effect of non-GAAP adjustments (6) $(0.02) $(0.01) $(0.01) $(0.01) $(0.01)
Income tax effect of valuation allowance (7) $0.04 - $0.02 - $0.02
Non-GAAP net income (loss) $0.17 $0.36 $0.47 $0.62 $0.62
Weighted average number of diluted shares (in K) 33,100 33,526 33,865 34,064 34,360
18
Reconciliation: GAAP Earnings Per Diluted Share to Non-
GAAP Earnings Per Diluted Share
(1) Amortization of intangible assets related to the Company's acquisitions of AIT, Marchi and Miconex
(2) Represents expense for termination benefits paid to former executives of the Company
(3) Adjustment to previous restructuring reserve related to the abandonment of one of the Company's facilities
(4) Impairment of assets classified as “held for sale” related to our 3D printing business in Singapore
(5) Amount paid related to the termination of a long-term contractual obligation to our 3D printing business in Singapore
(6) Tax effect on amortization of intangible assets, executive transition costs, restructuring charges, acquisition costs, impairment charges, and buy-out costs based on the non-GAAP tax rate
(7) The Company's GAAP tax expense is generally higher than the Company's non-GAAP tax expense, primarily due to losses in the U.S. with full federal and state valuation allowances. The Company's non-
GAAP tax rate and resulting non-GAAP tax expense considers the tax implications as if there was no federal or state valuation allowance position in effect