ESD Materials for Static Electricity Control

ESD plastics for static electricity control when handling semiconductor wafers

For certain semiconductor manufacturing processes, the plastics that come into contact with integrated circuits must be formulated to prevent the buildup and discharge of static electricity. Static electricity discharge can damage electronic components resulting in yield loss.

Surface resistivity describes the ability of a plastic material to dissipate static electricity. Plastics with surface resistivities in certain defined ranges are described as antistatic, static dissipative, or conductive per the diagram shown below.

surface resistivity ranges for esd plastics
  Metals Conductive
Plastics
Static Dissipative
Plastics
Antistatic
Plastics
Unfilled
Plastics
(Insulators)
Surface Resistivity Range (Ohm) 10-5 to 10-1 101 to 106 106 to 1012 1010 to 1012 >1012

Opaque ESD Engineering Plastic Materials

Opaque engineering plastics typically achieve ESD properties through the use of conductive additives. Some ESD additives are permanent and others may migrate out of a material over time. The surface resistivity effects from some ESD additives are dependent on the moisture levels in the environment. Other additives exhibit consistent resistivity in both dry and humid conditions.

Applications for ESD engineering plastics include:

  • Assembly fixtures
  • Testing fixtures
  • Integrated circuit chip trays and carriers
  • PCB board handling fixtures

The correct ESD engineering plastic to use for an application will depend on the desired surface resistivity range, the operating temperature, compatibility with process chemicals, dimensional stability requirements, and the desired mechanical properties.

The table below shows the surface resistivities as well as some of the key mechanical and thermal properties of engineering plastics that have been formulated for static electricity control.

ESD Plastic materials properties TABLE
  UHMW UHMW ACETAL ACETAL PET
  Polystone® M
ESD 90
Polystone® M
Black AST

TECAFORM®
AH SD
 
Semitron®
ESd 225
Semitron®
ESd 300 
ESD Category Static
Dissipative
Conductive Static 
Dissipative
Static 
Dissipative
Static 
Dissipative
Surface Resistance
per DIN IEC 60093 (ohm)
109 to 1011
Surface Resistivity
per ANSI/ESD STM 11.11 (ohm)
109 to 1011 105 to 109
Surface Resistivity
per DIN EN 62631-3-2 (ohm)
106 to 1011 <106
Tensile Strength
per ASTM D638 / ISO 527-1 (psi)
3,100 3,100 5,000 5,400 11,500
Tensile Modulus
per ASTM D638 (kpsi)
99 99 189 200 500
Flexural Modulus
per ASTM D790 (kpsi)
210 220 490
HDT @ 264 psi
per ASTM D648 (°F)
109 109 190 225 240
CLTE (in/in/°F x 10-5) 11.1 11.1 7.5 9.3 3.1
  ULTEM® PEI ULTEM® PEI ULTEM® PEI PTFE
  Semitron®
ESd 420V
Semitron®
ESd 420

Semitron®
ESd 410C
 
Semitron®
ESd 500HR
ESD Category Static
Dissipative
Static
Dissipative
Conductive Antistatic
Surface Resistance
per DIN IEC 60093 (ohm)
1010 to 1012
Surface Resistivity
per ANSI/ESD STM 11.11 (ohm)
106 to 109 106 to 109 104 to 106
Surface Resistivity
per DIN EN 62631-3-2 (ohm)
Tensile Strength
per ASTM D638 / ISO 527-1 (psi)
10,000 11,500 9,000 1,450
Tensile Modulus
per ASTM D638 (kpsi)
910 640 850 210
Flexural Modulus
per ASTM D790 (kpsi)
910 650 850
HDT @ 264 psi
per ASTM D648 (°F)
420 410 410 212
CLTE (in/in/°F x 10-5) 1.5 1.95 1.8 4.7
  PEEK PEEK PEEK PEEK PEEK
  Semitron®
ESd 490HR 
Semitron®
ESd HPV PEEK

Semitron®
ESd 480 
 
TECAPEEK®
SD Black
1TECAPEEK® ELS
Nano Black
ESD Category Antistatic Static 
Dissipative
Static 
Dissipative
Static 
Dissipative
Conductive
Surface Resistance
per DIN IEC 60093 (ohm)
10to 109 10to 104
Surface Resistivity
per ANSI/ESD STM 11.11 (ohm)
1010 to 1012 10to 109 10to 109
Surface Resistivity
per ASTM D 991 (ohm)
Tensile Strength
per ASTM D638 / ISO 527-1 (psi)
14,000 8,600 14,500 18,180 15,374
Tensile Modulus
per ASTM D638 (kpsi)
940 775 940 1,200 696
Flexural Modulus
per ASTM D790 (kpsi)
950 760 1,000 957 682
HDT @ 264 psi
per ASTM D648 (°F)
500 383 500
CLTE (in/in/°F x 10-5) 2.8 3.5 1.7 2.8 2.8
  PAI Polyimide
  Semitron®
ESd 520HR 
2DuPont™ Vespel®
SP-202
ESD Category Antistatic Conductive
Surface Resistance
per DIN IEC 60093 (ohm)
Surface Resistivity
per ANSI/ESD STM 11.11 (ohm)
1010 to 1012
Surface Resistivity
per ASTM D 991 (ohm)
<102
Tensile Strength
per ASTM D638 / ISO 527-1 (psi)
10,000 13,300
Tensile Modulus
per ASTM D638 (kpsi)
800 530
Flexural Modulus
per ASTM D790 (kpsi)
800 911
HDT @ 264 psi
per ASTM D648 (°F)
520
CLTE (in/in/°F x 10-5) 2.8 1.6

Notes:
1 The flexural modulus of TECAPEEK® ELS Nano Black was measured using ISO 178.
2 The properties for DuPont™ Vespel® SP-202 are measured perpendicular to the Z axis of the plaque.

Transparent EDS Plastic Materials

Transparent ESD acrylic, polycarbonate, PVC, and CPVC sheet materials achieve their electrical properties through the use of surface coatings. The correct transparent ESD plastic to use for an application will depend on the surface resistivity required, the required optical transparency and haze, the operating temperature, chemical resistance requirements, flammability requirements, and the desired mechanical properties.

The table below shows the surface resistivities as well as some of the key mechanical, thermal, and optical properties of various transparent plastic sheet materials that have been coated for static electricity control. 
 

transparent ESD Plastic materials properties TABLE
  ACRYLIC ACRYLIC POLYCARBONATE POLYCARBONATE
  AC-300™ AC-350™
(Bending Grade)
PC-300™ PC-350™
(Bending Grade)
ESD Category Static
Dissipative
Static
Dissipative
Static 
Dissipative
Static 
Dissipative
Surface Resistivity
per ASTM D257 (ohm/square)
106 to 108 106 to 108 106 to 108 106 to 108
Tensile Strength per
ASTM D638 / ISO 527-1 (psi)
10,000 10,000 9,500 9,500
Tensile Modulus per
ASTM D638 (kpsi)
400 400 340 340
Flexural Modulus per
ASTM D790 (kpsi)
475 475 340 340
HDT @ 264 psi per
ASTM D648 (°F)
210 210 270 270
CLTE (in/in /°F x 10-5) 3.5 3.5 3.8 3.8
Light Transmittance for
3mm Sheet per ASTM D1003 (%)
80 80 75 75
Haze per ASTM D1003 (%) <5 <5 <5 <5
UL 94 Rating of the
Uncoated Substrate
HB HB V-0 for ≥ 
0.236" thick
V-0 for ≥ 
0.236" thick
Factory Mutual Test
Protocol (Class 4910)
  PVC PVC CPVC CPVC
  PVC-300™ PVC-350™
(Bending Grade)
CPVC-300™ CPVC-350™
(Bending Grade)
ESD Category Static
Dissipative
Static
Dissipative
Static 
Dissipative
Static 
Dissipative
Surface Resistivity
per ASTM D257 (ohm/square)
106 to 108 106 to 108 106 to 108 106 to 108
Tensile Strength per
ASTM D638 / ISO 527-1 (psi)
10,000 10,000 9,000 9,000
Tensile Modulus per
ASTM D638 (kpsi)
425 425 480 480
Flexural Modulus per
ASTM D790 (kpsi)
425 425 450 450
HDT @ 264 psi per
ASTM D648 (°F)
140 140 177 177
CLTE (in/in /°F x 10-5) 7.0 7.0 7.0 7.0
Light Transmittance for
3mm Sheet per ASTM D1003 (%)
75 75 60 60
Haze per ASTM D1003 (%) <5 <5 10 10
UL 94 Rating of the
Uncoated Substrate
V-0 V-0 V-0 V-0
Factory Mutual Test
Protocol (Class 4910)
Listed as
Approved
Listed as
Approved

Note:
Typical property values for 1/4" thick sheet unless otherwise noted.

Which plastic materials are right for your application? Contact us today.

Looking for plastic materials that minimize the buildup and discharge of static electricity, which can damage IC chips? Whatever you need, our plastics experts are here for you—ready to answer your technical questions and discuss material options.

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Frequently Asked Questions
Which plastics can help to limit damage from electrostatic discharge?

Curbell supplies a wide range of plastics with surface resistivities in the conductive, static dissipative, and antistatic ranges. These materials have been used for wafer handling applications where electrostatic discharge is a concern.

Are the ESD properties of plastics affected by the level of humidity in the air?

Most ESD plastics are formulated with additives that are not affected by the level of humidity in the air. However, some ESD formulations depend on atmospheric humidity to achieve reduced surface resistivity levels and they will exhibit higher resistivity in dry conditions.

Can the ESD properties of a plastic material change over time?

Most ESD plastics are formulated with non-migrating additives, resulting in stable surface resistivity over time. However, some ESD formulations include migrating additives that can gradually migrate out of a part, particularly if the part is frequently cleaned.

Once a plastic sheet or rod is machined, will it still have ESD properties?

Most ESD plastics have the additive throughout the material and they will maintain their ESD properties when machined into finished parts. However, transparent ESD materials achieve their static control properties through the use of coatings. Once the coated surfaces are machined away, they would have to be recoated to have ESD performance.