Delrin ® Acetal Homopolyme CNC processing component

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Product details

In the semiconductor industry, POM (polyoxymethylene) is primarily used to manufacture structural components and fixtures requiring high cleanliness, high dimensional stability, antistatic properties, and wear resistance. It is commonly found in wafer transport, packaging and testing, and cleanroom automation equipment.

Wafer transport and positioning components: such as orientation devices, clamps, and vacuum chuck supports, utilize antistatic/static dissipation grade POM (surface resistivity 10⁸–10¹⁰Ω) to prevent ESD damage to exposed workpieces. Its low workpiece adhesion also meets ISO 4-7 cleanroom requirements.

Packaging and testing fixtures: used for chip test sockets, carrier tapes, and tip stage sliding components. These fixtures must balance mechanical precision (POM has a low coefficient of thermal expansion ≈ 8–9 × 10⁻⁵/K), dimensional stability (water absorption <0.25%), and friction coefficient and wear resistance. Some utilize carbon fiber reinforced POM to improve bridging and conductivity (volume resistivity can reach 10³-10⁶ Ω·cm). Robotic arms and automation components: Lightweight transmission components in semiconductor devices (such as harmonic canceller components and vacuum robotic arm joints) use high-rigidity or glass fiber reinforced POM to replace metals in order to reduce weight, eliminate and reduce harmonic interference.

Non-metallic vacuum components and insulating supports: Due to its intrinsic insulation (volume resistivity >10¹⁴ Ω·cm) and resistance to vacuum gas release (compliant with SEMI standards), POM is used for non-load-bearing insulating components or isolation structures within vacuum chambers; however, grades containing halogens or metal ion leaching should be avoided (e.g., certain modified POMs require SEMI F47/F55 certification).

Note: Pure POM is an insulator; almost all semiconductor applications use modified grades (carbon black, carbon fiber, or bulk permanent antistatic agents); strict temperature control (<215°C) is required during processing to prevent formaldehyde release, and it is not resistant to strong acids (such as HF, H₂SO₄), therefore it is not used for components in wet etching or cleaning tanks that come into contact with chemicals (in which case PPS, PVDF, or PFA are often used). Typical commercial grades include DuPont Delrin® 100ST (10% carbon fiber, electrostatic dissipation), Celanese Celcon® M (antistatic grade), and Ensinger TECAFORM AH ELS black.

Which should you choose when making semiconductor jigs: PEI sheets or anti-static POM sheets?

Both PEI sheets and anti-static POM sheets are commonly used in semiconductor jig manufacturing, but they are suitable for different working conditions. The key to material selection isn't simply comparing "which is better," but rather considering the process environment of the jig, including:

Temperature

Cleanliness level

Electrostatic control requirements

Dimensional accuracy

Chemical environment

Mechanical load

Lifespan

For high-temperature, high-cleanliness, and high-precision semiconductor equipment, PEI is generally more suitable.

For room-temperature anti-static handling and low-friction moving structures, anti-static POM is often more economical and practical.

The biggest difference between the two is primarily their temperature resistance.

PEI (polyetherimide) is a high-performance engineering plastic with a long-term operating temperature typically reaching around 170℃. It maintains good mechanical strength and dimensional stability even at high temperatures.

Therefore, many applications utilize PEI, including:

Wafer processing fixtures, semiconductor thermal process fixtures, high-temperature carriers, cavity insulation structures, and SMT high-temperature fixtures.

Especially when in prolonged contact with heat sources inside equipment, PEI is less prone to softening and deformation.

In contrast, antistatic POM (polyoxymethylene) typically has a long-term operating temperature of around 80℃ to 100℃, exhibiting significantly lower high-temperature stability than PEI. Although POM has good wear resistance and excellent machinability, it is prone to thermal deformation under high-temperature processing conditions.

Therefore, if the process temperature is high, PEI has a clear advantage.

The second important difference is cleanliness stability.

The semiconductor industry highly values:

Particulate precipitation, volatile contamination, dimensional stability, and thermal expansion control. Due to its stable molecular structure, PEI exhibits low precipitation and low volatility under high-temperature environments, making it widely used in semiconductor equipment.

Especially in:

Wafer contact components, vacuum environment structures, and cavity internal insulation components.

In comparison, PEI is easier to meet cleanliness requirements.

While POM has excellent machinability, it typically produces more surface abrasive particles than PEI during high-speed friction or long-term operation. Therefore, PEI is more commonly used in the core areas of high-cleanliness equipment.

However, POM also has its own distinct advantages.

The biggest advantages are:

Wear resistance, low friction, ease of machining, and low cost. Antistatic POM is very common in automated material handling structures.

For example:

Wafer handling slides, automated grippers, guide wheels, transmission structures, and buffer components. Because of its low coefficient of friction, POM moves smoothly, and its long-term sliding performance is generally superior to PEI.

Furthermore, POM has high machining efficiency and excellent cutting performance, making it more suitable for complex batch processing.

PEI, on the other hand, has higher hardness, resulting in relatively higher machining costs.

The third key difference is antistatic stability.

Antistatic POM typically achieves stable surface resistance by adding conductive fillers, therefore:

Its antistatic performance is mature, its cost is relatively low, and it is suitable for conventional ESD control.

PEI can also be made in anti-static grades, for example:

Anti-static PEI

Conductive PEI

ESD PEI

However, the cost is usually significantly higher than anti-static POM.

However, in high-temperature environments, anti-static PEI generally has more reliable electrostatic stability because the electrical properties of ordinary POM may fluctuate more significantly with increasing temperature.

From a mechanical property perspective:

PEI:

Higher rigidity

Better thermal stability

More stable dimensional accuracy

POM:

Better toughness

Better sliding performance

Stronger wear resistance

Therefore, in practical applications, the two materials are often used in a differentiated manner.

For example:

PEI is used for high-temperature precision positioning structures