PI vs PEEK Materials: Comparison & Respective Advantages in Electronic & Semiconductor Applications

As the electronic semiconductor industry continues to evolve toward higher integration, high-frequency and high-speed transmission, ultra-high cleanliness, and reliability in harsh environments, high-performance specialty engineering plastics have become critical basic materials affecting chip manufacturing, packaging, testing, and equipment component stability. Polyimide (PI) and Polyetheretherketone (PEEK) are the two most widely used high-temperature polymer materials in the semiconductor sector, with distinct differences in performance, applicable scenarios, and core advantages. This article analyzes their performance comparison, typical applications, and selection logic in electronic and semiconductor fields to help semiconductor equipment engineers, material purchasers, and process researchers choose suitable materials accurately.

In semiconductor manufacturing and packaging, temperature resistance, electrical properties, chemical stability, cleanliness, and dimensional stability are key indicators determining material feasibility. PI stands out for its ultra-high temperature resistance, excellent dielectric properties, radiation resistance, and low coefficient of thermal expansion. It can withstand long-term service temperatures above 300℃ and short-term temperatures close to 500℃, while offering extremely low dielectric constant and loss, ensuring stable high-frequency signal transmission with minimal attenuation or crosstalk. Additionally, PI resists UV and high-energy radiation, tolerates most photoresists and developers, and features low outgassing and low precipitation, making it ideal for high-precision, high-temperature, and high-frequency semiconductor components.

PEEK, by contrast, excels in balanced mechanical properties, high cleanliness, excellent wear and creep resistance, and strong chemical corrosion resistance. With a long-term operating temperature of approximately 250℃, it covers most semiconductor process conditions. PEEK offers outstanding resistance to hydrolysis, acids, alkalis, and fluorine-based plasma, especially hydrofluoric acid and high-temperature cleaning solutions. It has a low friction coefficient, high wear resistance, minimal particle generation, and extremely low ion extraction, fully meeting SEMI cleanroom standards. PEEK provides superior cost-performance and reliability in wafer handling, precision structural parts, and corrosion-resistant components.

PI’s core advantages in electronics and semiconductors first lie in advanced packaging and high-frequency high-speed electronic components. PI film is the key substrate for flexible printed circuits (FPC), interlayer dielectric materials in chip packaging, and flexible chip substrates. With low dielectric loss and high dimensional stability, it is perfectly suitable for high-frequency and high-speed applications such as 5G communication chips, AI computing chips, and millimeter-wave devices. In chip testing, PI is widely used in probe card substrates and test socket insulation parts, maintaining insulation and dimensional accuracy during high-temperature testing to avoid signal distortion.

Furthermore, PI is irreplaceable in high-temperature semiconductor processing equipment. It is used for high-temperature insulation supports, thermal insulation parts, and lithography carriers in ion implantation, CVD deposition, and high-temperature annealing systems, retaining structural stability under high vacuum, strong radiation, and extreme heat without deformation or contamination. For aerospace and military-grade semiconductors, PI’s radiation resistance and thermal cycle stability make it the preferred insulation material for extreme environments.

PEEK applications in semiconductors focus more on high-cleanliness, high-wear-resistance, and high-corrosion-resistance structural and functional parts. Wafer manufacturing has extremely strict contamination control, and PEEK components such as wafer grippers, end effectors, support rings, and FOUP parts produce no dust or metal ions during handling, avoiding wafer scratching. They also withstand repeated high-temperature and strong-acid cleaning, offering much longer service life than general engineering plastics.

In etching equipment, CMP systems, and ultrapure water pipelines, PEEK is used for showerheads, fluid valves, polishing retainer rings, and pipe fittings. Its strong chemical resistance protects against process chemicals, while high rigidity and creep resistance prevent deformation during long-term operation, effectively improving equipment stability and chip yield. PEEK is also applied in semiconductor packaging molds, high-frequency connector housings, and sensor structures, combining insulation, structural strength, and high-temperature stability for reliable performance in packaging and testing processes below 260℃.

In summary, the selection between PI and PEEK follows clear logic. PI is preferred for components requiring long-term exposure to temperatures above 300℃, high-frequency and high-speed chips, flexible substrates, probe cards, radiation-resistant parts in lithography and ion implanters, and precision microelectronic structures demanding ultra-high dimensional stability.

PEEK is more suitable for wafer handling, clamping, and storage components requiring high cleanliness and low precipitation; parts exposed to hydrofluoric acid, acid-base solutions, and steam cleaning in etching and CMP; wear-resistant and creep-resistant structural components; and general packaging, testing, and fluid control parts operating below 260℃.

In actual semiconductor production lines and equipment design, PI and PEEK are often combined, with PI providing high-frequency insulation and high-temperature performance and PEEK delivering structural support and clean wear resistance for complementary performance. As semiconductor processes advance toward smaller nodes, requirements for material purity, stability, and functionality will keep rising, ensuring PI and PEEK remain irreplaceable core specialty polymer materials in the advanced electronics and semiconductor industry.