the basic concept of the gas filter

創新需求需求再造

The Basic Concept of the Gas Filter

主講人 : 龍仁生

技術研討資料


Content

How do gas filters work ? Basic requirements of gas filter Filter material comparison Filter lifetime recommendation Case study How to choose a suitable filter ? Filter technology trend Summary

Mykrolis 台灣分公司‧微電子事業處


How do Gas Filters Work

Particle capture mechanismsImpactionInterceptionDiffusionElectrostatic

MPPS (Most Penetrating Particle Size) Nature of gas



MILLIPORE Mykrolis 台灣分公司‧微電子事業處

How do Gas Filters Work

DiffusionInertialImpaction

GravitationalSettling Interception

FiberCross

Section

FluidStreamlines

ElectrostaticDeposition



Theoretical Plot illustrating the Most Penetrating Particle

Size Concept

10

Capture byInterception

Capture byDiffusion

CombinesCapture byInterception

andDiffusion

MostPenetratingParticle Sizeat 50 cm sec.

10

10

10

10

10

10

10

10

10

10

10

10

10

.01 .02 .03 .06 .1 .2 .3Particle Diameter, m

-28

-26

-24

-22

-20

-18

-16

-14

-12

-10

-8

-6

-4

-2

Fra

ctio

nal P

enet

ratio

n


MILLIPORE Mykrolis 台灣分公司‧微電子事業處

Particle Capture on Nickel Membrane

Particles

3m



Log Reduction Value

LRV = Log10 (inlet Cp / outlet Cp)

Example:– Inlet Cp = 1 x 10^6 particles / ft3–Outlet Cp = 1 particle / ft3–LRV = 6–99.9999% efficient– fractional penetration = 1 x10^-6


Basic requirements of gas filter

High retention- The ability to retain all particles,down to the smallest size.

Downstream cleanliness- The ability not to add anything ( particles or volatiles (moisture, others))to the gas stream.

High corrosion resistance- The ability to withstand in a corrosive environment.

Fast gas displacement- The ability to displace gas quickly.



Filter Membrane Comparison

Materials

Of

Membrane

Shedding

Retention

(LRV) Outgasing

Gas

Displacement

Corrosion

Resistance

Nickel Excellent >10.8 Excellent Excellent Good

SUS316L Excellent 6.2 Good Excellent Fair

PTFE Good >10.8 Poor Poor N/A

Ceramic Fair 7.8 Fair Poor N/A



Filters Lifetime Recommendation

• Specialty Gas (Cl2, HBr, SiH4, DCS…) < 2 Years

• Inert Gas (N2, H2, O2, He…)< 5 Years


創新需求需求再造• No.1 Upstream

SEM and EDS• No.2 Upstream

SEM and EDS


創新需求需求再造• No.1 downstream

SEM and EDS• No.2 downstream

SEM and EDS


創新需求需求再造• No.1 Housing SEM

and EDS (corroded)

• No.2 Housing SEM and EDS (corroded)



How to Choose a Suitable Filter

• Compatibility (Corrosive / Inert)Corrosive: Ni / PTFE

Inert : Ni / PTFE / SS• Retention N

i / PTFE > SS• Gas flow rate in need • Considering Inlet pressure• Fitting (VCR, Swaglok, Butt weld, IGS(Surface

Mount))



Filter Technology Trend

• Improve Process uptime & Wafer defects.

• Overall Process control: Particles, Moisture, Oxygen,Impurity…etc.

• Our best suggestion is both of Filter & Purifier can improve process uptime & overcome wafer defects.



The Role of Purifier

• Purifier play a role of remove impurities (Oxygen, Moisture,CO2…etc)

• Moisture is one factor cause corrosion on component & piping to process chamber.(Especially, Corrosive gas)

• Moisture & Impurity can affect the process uptime & wafer defects.



Summary Gas filter key filtrate mechanism : diffusion &

interception Cleanliness becomes most important All-Metal gas filters are the technology trend Routine filter change out is the key to high

quality particle performance Purifier can enhance gas filter performance

and lifetime


the basic concept of the gas filter

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