Micro-Nano Processing: Femtosecond Laser vs. Picosecond Laser – How to Choose Tool?
In high-precision fields such as microelectronic manufacturing, medical device R...
MONO | 2025-11
INDUSTRY
Ultrafast laser processing provides high precision and cleanliness for polyimide materials used in the medical and microelectronics industries.
Polyimide (PI), a type of thermosetting resin classified as a super engineering plastic, is a typical representative of polymers.
Its core properties include: excellent high-temperature resistance (with a long-term service temperature of 200-300°C), outstanding mechanical stability, electrical insulation, chemical inertness, and biocompatibility. Thus, its processing technology is widely applied in high-end manufacturing fields.
In the semiconductor industry, polyimide is widely used as an insulating material for semiconductor-related components, and also plays an important role in protective materials, high-performance adhesives, heat-resistant coatings, etc.
In the field of microelectronic components, polyimide is used in wafer carriers, test fixtures, hard disk drive components, electrical connectors, wire insulation layers, flexible printed circuit boards, and core components of digital copiers and inkjet printers.
Thanks to its excellent chemical inertness and biocompatibility, polyimide is increasingly used in the medical field, such as cardiovascular catheters, retrieval devices, push rings, marker bands, angioplasty instruments, stent delivery systems, neurointerventional devices, and drug delivery devices.
1. When processing medical-grade polyimide hoses (e.g., drilling, cutting), the core standard is to ensure no harmful substances are introduced during manufacturing. Therefore, the cleanliness of the material itself and the surrounding environment must be maintained throughout the process.
2. Polyimide’s "high-temperature resistance" refers to its thermal stability during long-term use, but it has low thermal conductivity and is highly sensitive to heat during processing. Local instantaneous high temperatures can cause molecular chain breakage and carbonization, leading to significant heat-affected zones (HAZ), material warping, and particularly obvious thermal damage to edges after laser cutting, especially for thin-walled products. Thus, "cold processing" is required.
3. Although picosecond lasers can process precise micron-level features on polyimide films, they have obvious limitations: first, molten debris tends to form around the features after processing, requiring post-treatment of samples to remove surface residues, which increases overall costs; second, the spacing of processed features is limited, restricting the improvement of feature density and the miniaturization of products.
Illustration: Comparison of picosecond processing vs. femtosecond laser processing effects
As a non-contact processing tool, femtosecond laser technology can focus the beam to the micron level and belongs to "cold processing," making it ideal for precision machining of polyimide materials.
• Minimal thermal impact: The high peak power of femtosecond laser pulses can instantly vaporize polyimide films, ensuring no debris remains on the surface, avoiding significant thermal effects. Processed microholes can be arranged more closely without mutual interference, which helps improve feature density.
• No post-treatment required: The sidewalls and edges of processed holes are smooth, eliminating the need for additional grinding or polishing to remove raised edges, simplifying the process flow.
• Wide material adaptability: It can process almost all materials. Polymers such as polyimide have weak absorption of infrared rays; for most transparent PI materials, ultraviolet ultrafast lasers are required to ensure processing efficiency.
• Capability to process deep holes: It can achieve deep hole structures with an aspect ratio greater than 10:1.
• Flexibility: Integrated cutting and drilling can improve production efficiency, processing speed, and process flexibility. Real-time monitoring and adjustment of shapes and sizes can be achieved through software systems.
1. Processing of polyimide microhole arrays
Stable processing of 3μm-diameter microholes on polyimide sheets, with precision controlled within ±1μm.
2. Processing of straight through-holes in polyimide tubes
It can process high-cleanliness, high-precision holes without damaging the other side of the tube, with no need for post-processing.
High-repetition-rate femtosecond laser cutting equipment enables high-throughput processing of polymers, with a cutting speed of nearly 300 mm/s. It should be noted that using shorter wavelengths can improve processing quality, but the lower average power at shorter wavelengths may require a trade-off in speed.
Etching of micro-bump structures on PI film surfaces, with a bump depth of 0.026mm, surface roughness Ra ≤ 0.4μm, no burrs, and no deformation.
Femtosecond lasers precisely strip polyimide coatings from medical wires without damaging the wire substrate, ensuring smooth stripping edges and meeting medical-grade cleanliness requirements.
Typical applications of femtosecond lasers in polymer processing and polyimide structuring also include:
flexible ultra-thin printed circuit boards (PCBs) for small mobile devices;
flexible solar cells;
micro hearing aid components;
flexible organic light-emitting diode (OLED) display panels;
and perforated filters for food and medical fields.
