CVD Chemical Vapor Deposition
Parylene Materials

        CVD uses a long chain protective polymer material called parylene. It can be deposited in vacuum. The good penetrating power of the active molecule can form no pinhole around the bottom of the element and transparent insulating coating of uniform thickness provides high quality protective coating for the component. Resist the damage of acid-base salt spray and various corrosive gas. Because the liquid is not used, there is no aggregation in the coating process, and the bridge forms the meniscus. Macromolecular materials can be classified as N type、C type、 D type、F type and HT type according to their molecular structure. 


Raw material grades

Film forming property

CAT

N type

CAT

C type

CAT

D type

CAT

F(VT4) type

CAT

AF4(HT) type

Density(gm/cc)

1.1

1.3

1.41

1.55

1.5

Dielectric constant(1Mhz)

2.6

2.9

2.8

2.3

2.2

Dielectric strength(V/Mil)

7000

5600

5500

5000

7000

Minimum continuous

working temperature(in the air)

-60°C

-60°C

-60°C

-60°C

-60°C

Maximum continuous 

working temperature(in the air)

60°C

80°C

110°C

200°C

300°C

Friction coefficient-dynamic condition

0.25

0.29

0.38

0.39

0.16

Coefficient of linear expansion

(ppm at 25°C)

69

35

38

45

34

Hydroscopicity(after 24H)

<% 0.1

<% 0.1

<% 0.1

<% 0.1

<% 0.1

WVTR (gm.mm)/m2.day)

0.6

0.08-0.1

0.1

0.25-0.32

0.2

OTR (cc.mm)/(m2.day.atm)

16

3

12.0-13.5

16.8

25.3