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Precision Micro-Drilling in Ceramic and Ferrite Inductors: The Green Picosecond Advantage
Driven by the rapid growth of 5G communications, automotive electronics, and high-frequency RF modules, electronic components are scaling down to sub-millimeter packages such as 01005 and 008004.
To deliver higher power density within miniaturized footprints, inductor designs are shifting from traditional two-dimensional layouts toward 3D vertical stacked architectures.
Manufacturing high-density 3D ceramic inductors and ferrite power inductors requires high-aspect-ratio vertical interconnect accesses (via-holes) through ultra-fragile, heat-sensitive substrates.
Traditional mechanical drilling and nanosecond thermal laser processing frequently cause micro-cracks, severe edge chipping, and magnetic property degradation.
Green picosecond laser technology (532 nm ultrafast laser) has emerged as the premier solution, enabling precise, stress-free micro-machining for next-generation inductive components.
Technical Superiority of 532 nm Green Picosecond Lasers
Green picosecond lasers combine ultra-short pulse durations (10-12 s) with shorter optical wavelengths, outperforming standard infrared (1064 nm) systems across several critical physical dimensions:
Enhanced Optical Absorption: Ferrite and functional ceramic substrates exhibit significantly higher absorption rates at the 532 nm green wavelength. This allows material removal at lower energy fluences, preventing thermal over-exposure.
Diffraction-Limited Spot Size: Because the wavelength is half that of infrared light, green lasers can be focused into tighter beam spots. This capability enables sub-20-micron micro-via creation with extreme spatial resolution.
Non-Thermal Cold Ablation: Picosecond pulses deposit energy directly into the material's electronic system before thermal energy can dissipate into the surrounding crystal lattice. This completely eliminates heat-affected zones (HAZ), micro-cracks, and recast layers.
Key Applications in Ceramic and Ferrite Inductor Manufacturing
1. High-Aspect-Ratio Via-Hole Drilling in Ferrite Core Inductors
Power inductors require conductive micro-vias through ferrite cores to establish vertical interconnects for copper or silver metallization.
The Challenge: Ferrite is highly brittle and sensitive to thermal stress. Conventional laser heat causes structural micro-fissures that degrade magnetic permeability ($\mu$) and increase core loss.
The Green Picosecond Solution: Ultrafast green laser drilling executes clean photo-ablation without thermal stress. The smooth inner hole walls preserve the Curie temperature and intrinsic magnetic properties of the ferrite core.
2. 3D Interconnects for LTCC and HTCC Multilayer Inductors
High-frequency RF inductors rely on Low-Temperature Co-Fired Ceramic (LTCC) layer stacking. Creating inter-layer coil connections through thin ceramic tapes demands strict taper control and pristine hole margins.
The Green Picosecond Solution: Integrated with precession motion optics, green picosecond lasers produce straight, near-zero-taper via walls at aspect ratios exceeding 8:1, facilitating seamless conductive paste filling.
3. Precision Scribing and Dicing of Ceramic Substrates
Mass production of chip inductors requires dense array scribing across large ceramic wafers prior to singulation.
The Green Picosecond Solution: By confining edge chipping to under 3 microns, ultrafast green lasers maintain the mechanical integrity of individual chips and dramatically improve final assembly yield.
Performance Benchmark Summary
To illustrate the technical transition from legacy tools to ultrafast green lasers, consider these key operational metrics:
Minimizing Via Diameter: Legacy nanosecond lasers are generally restricted to hole diameters above 50 microns. Green picosecond lasers routinely achieve precise via diameters between 15 and 30 microns, directly accommodating ultra-small component packages.
Eliminating Thermal Affected Zone (HAZ): Thermal damage from nanosecond lasers often exceeds 20 microns, creating internal stress. Green picosecond processing reduces HAZ to under 2 microns, protecting delicate magnetic domains.
Controlling Edge Chipping: Traditional methods yield edge chipping greater than 15 microns. Green picosecond lasers reduce chipping to under 3 microns, substantially boosting structural strength under mechanical shock.
Optimizing Wall Geometry: Nanosecond drilling produces noticeable funnel-shaped tapers that complicate metallization. Green picosecond drilling delivers near-vertical via walls, ensuring dense, defect-free electroplating fill.
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What are the precautions for operating a laser marking machine?
1. It is strictly prohibited to start the laser power supply and Q-switching power supply when there is no water or the water circulation is abnormal.
2. The Q power supply is not allowed to operate without load (i.e., the output terminal of the Q power supply should be left floating).
3. In case of any abnormal phenomenon, first turn off the galvanometer switch and the key switch, and then conduct a check.
4. It is not allowed to start other components before the krypton lamp is lit to prevent high voltage from entering and damaging the components.
5. Pay attention to leaving the output terminal (anode) of the laser power supply suspended to prevent sparking and breakdown with other electrical appliances.
6. Keep the internal circulating water clean. Regularly clean the water tank and replace it with clean deionized water or pure water.
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What should we do when laser intensity decreases and the marking is not clear enough?
1. Turn off the machine and check if the laser resonant cavity has changed; Fine-tune the resonant cavity lens. Make the output light spot the best;
2. The acousto-optic crystal is offset or the output energy of the acousto-optic power supply is too low;
Adjust the position of the audio-visual crystal or increase the working current of the audio-visual power supply;
3. The laser entering the galvanometer deviates from the center: Adjust the laser;
4. If the current is adjusted to around 20A but the light sensitivity is still insufficient: the krypton lamp is aging. Replace it with a new one.
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How to maintain a UV laser cutting machine?
1. It is required to carry out regular cleaning every day, remove debris from the countertop, limiters and guide rails, and spray lubricating oil on the guide rails
2. The waste materials in the collection box should be cleared regularly to prevent excessive waste from blocking the exhaust port.
3. Clean the chiller once every 15 days, drain all the internal water, and then fill it with fresh pure water.
4. The reflector and focusing lens should be wiped with a special cleaning solution every 6 to 8 hours.
When wiping, use a cotton swab or cotton swab dipped in the cleaning solution to wipe from the center to the edge of the focusing lens in a counterclockwise direction.
At the same time, be careful not to scratch the lens.
5. The indoor environment can affect the lifespan of the machine, especially in damp and dusty conditions.
A damp environment is prone to causing rust on the reflective lenses and also easily leading to short circuits, discharge and sparking of the velvet laser.
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What accidents might be caused by the laser emission when using a laser cutting machine?
(1) A fire was caused by the laser coming into contact with flammable materials.
Everyone knows that the power of laser generators is very high, especially when it comes to high-power laser cutting machines, the temperature of the emitted laser is extremely high. The possibility of a fire being caused when a laser beam comes into contact with flammable objects is very high.
(2) Harmful gases may be produced when the machine is in operation.
For instance, when cutting with oxygen, it undergoes a chemical reaction with the cutting material, generating unknown chemical substances or fine particles and other impurities. After being absorbed by the human body, it may cause allergic reactions or discomfort in the lungs and other respiratory tracts. Protective measures should be taken when conducting work.
(3) Direct laser exposure to the human body can be harmful.
The damage caused by lasers to the human body mainly includes damage to the eyes and skin. Among the harms caused by lasers, the damage to the eyes is the most severe. Moreover, damage to the eyes is permanent. So when doing homework, you must pay attention to protecting your eyes.
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What is the focused spot diameter of nanosecond, picosecond and femtosecond laser?
Nanosecond: The light spot is 0.5-1mm.
Picosecond: The focused spot is around 0.02mm.
Femtosecond: Under the action of a laser beam with a high repetition rate of 100-200KHz and a very short pulse width of 10ps,
the focused spot diameter is as small as 0.003mm.
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What are the main applications of UV laser cutting machine?
The UV laser cutting machine can be used for cutting and depaneling PCB.
It can precisely cut and shape various types of PCB circuit boards with V-CUT and stamp holes, and open Windows and covers.
It can also be used for separating packaged circuit boards and ordinary smooth boards.
It is suitable for cutting various types of PCB substrates, such as ceramic substrates, rigid-flex boards, FR4, PCBs, FPCs, fingerprint recognition modules, cover films, composite materials, copper substrates, aluminum substrates, etc.
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Precautions for laser cutting machines to process various metal materials?
Copper and brass:
Both materials have high reflectivity and excellent thermal conductivity.
Brass with a thickness of less than 1mm can be processed by nitrogen laser cutting.
Copper with a thickness of less than 2mm can be cut. The gas used for laser cutting processing must be oxygen.
Copper and brass can only be cut when a "reflective absorption" device is installed on the system. Otherwise, reflection will damage the optical components.
Synthetic materials:
Processable synthetic materials include: thermoplastics, thermosetting materials and artificial rubber.
Aluminum:
Despite its high reflectivity and thermal conductivity, aluminum materials with a thickness of less than 6mm can be cut, depending on the type of alloy and the capacity of the laser.
When cutting with oxygen, the cutting surface is rough and hard.
When nitrogen is used, the cutting surface is smooth.
Pure aluminum is extremely difficult to cut due to its high purity.
Only when a "reflection and absorption" device is installed on the fiber laser cutting machine system can aluminum materials be cut.
Otherwise, reflection will damage the optical components
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What should be paid attention to when laser cutting stainless steel?
Laser cutting processing of stainless steel requires the use of oxygen, under the condition that edge oxidation is not a concern.
If nitrogen is used to achieve an edge free of oxidation and burrs, no further processing is required.
Coating an oil film on the surface of the sheet will achieve a better perforation effect without reducing the processing quality.