OPTOELECTRONICS
large, and were expensive to manufacture. For example, during assembly, each laser diode had to be put into operation to check its correct alignment – a process known as active alignment.
Integrating optical components on the die
Modern semiconductor technology offers methods to produce optical components on substrates using CMOS lithography. The result is a so-called photonic integrated circuit (PIC), which for example integrates optical waveguides and receivers. This has opened up the possibility of signifi cantly reducing the number of components required, the size, and the assembly costs. Laser diodes serve as light-emitting components in the optocouplers, which are placed and fi xed directly on the PICs using a die bonder. In chip production, die bonders place and wire or solder semiconductor wafers, known as dies, into packages. These devices work so precisely that active alignment is no longer necessary when placing the laser diode. This eliminates the most labor-intensive assembly step in the manufacture of optical transceivers.
The technology of maximum integration of electrical and optical components, also known as silicon photonics (SiPh), requires a new generation of high-precision bonders. For example, a laser diode must be placed with <± 0.5 µm at 3 sigma (3� process capability). This is the only way to manufacture an optocoupler that meets the strict specifi cations for avoiding light scattering and refl ection.
Even more precise
ASMPT has developed such high-precision bonders, which have proven themselves in optoelectronics. With AMICRA NANO, the manufacturer has launched the fi rst in the
CPO with External Laser SFP (ELSFP) as the signal carrier. Laser light sources are in SFP placed ex- ternally at the faceplate, and modulations are kept at the CPO. Fibre connections replace the original copper traces. (Image: ASMPT)
industry to achieve a positioning accuracy of <± 0.2 µm at 3 sigma. This precision is based on technology that is solid in every sense of the word: the entire positioning unit of the machine rests on a heavy, air-suspended granite plate to dampen external vibrations.
In-line control
AMICRA NANO: The bonder for processing optical and electronic components. The most precise machine currently on the market operates with a placement accuracy of <± 0.2 µm at 3 sigma (Image: ASMPT)
The chips to be placed are fed individually or as pre-separated wafers. A high- precision vacuum pipette then places them on a wafer or a single substrate. Continuous quality control: the machine’s so-called look-through placement head is designed in such a way that the high- resolution component camera can image the pipette from above. The pipette grips the die to be applied in such a way that it protrudes slightly on one side. This leaves fi ducial marks visible on the die, which the system uses for orientation. There are corresponding fi ducials on the substrate, which are also used for exact positioning. ASMPT is also a leading manufacturer in the fi eld of electronics assembly, so it is hardly surprising that the process here is similar to SMT processes. The part to be placed is fi rst inspected. Visually detectable defects lead to rejection. Once aligned, the chip is placed with a precisely defi ned bond force and then measured again. If the values are still within the permissible tolerance range after the second measurement, the chip is fi xed in place by laser welding, gluing, or a combination of contact pressure and heat. The machine is very fl exible when it comes to bonding techniques: it can perform both direct and indirect hybrid bonding as well as various soldering and adhesive bonding processes. The die and fl ip chip bonder offers three different heating options, including a laser soldering system and UV curing.
Since many processes are very sensitive to contamination, the machine is equipped with a HEPA fi lter and ionization system that ensures a high-purity working environment.
Great potential
There is great potential in modern multi-chip packages, especially in the fi eld of optical components. Manufacturers have different objectives and approaches. In the fi eld of high-precision die bonders in particular, machines are often designed individually according to customer specifi cations. A wide range of options is available. For example, there is software for complete traceability of all processed parts – particularly interesting for automotive suppliers, as customers demand absolute traceability. AMICRA machines can also be equipped with a repair function that removes incorrectly positioned parts from the substrate, provided this is technically possible. A fl ip chip option is also part of the portfolio.
Conclusion
The synthesis of optics and electronics is a signifi cant technological development, particularly, but not only in communications technology. High integration density in production is becoming increasingly important: the closer components are brought together, and the fewer individual parts need to be assembled per unit, the more effective, energy-effi cient and cost- saving the product is. However, the next level of integration of the key technologies of silicon photonics and co-packaged optics requires a manufacturing technology that also breaks new ground in terms of precision and process stability. Machines such as the AMICRA NANO set standards that the industry will have to follow in the future.
FEBRUARY 2026 | ELECTRONICS FOR ENGINEERS 41
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50
