Economics of Microlamination

A key impediment to the proliferation of MECS technology will be its economical production. It is expected that along with the diversity of MECS products that will be developed, there will be a similar diversity with regards to how they are made. Fig. 14.22 shows the unit costs associated with four different microlamination platforms based on photochemical machining (PCM) or blanking/punching (BLK) combined with diffusion bonding (DB) or surface mount technology (SMT). Clearly, the unit cost of MECS devices is better when using blanking/punching and surface mount technology. These improvements are mainly due to decreased cycle times. However, surface mount technology provides the added benefit of reducing the number of laminae needed since the channel laminae are printed using solder paste.

$60 $50 $40 $30 $20 $10 $0

1-1

J-

J-

□ Registration

PCM-DB BLK-DB PCM-SMT BLK-SMT Microlamination Platform

□ Patterning

□ Registration

PCM-DB BLK-DB PCM-SMT BLK-SMT Microlamination Platform

$49.45

$37.27

$1891 $14 75

Microlamination Platform

BLK-SMT

PCM-DB BLK-DB PCM-SMT

Microlamination Platform

BLK-SMT

Fig. 14.22. Unit cost for producing a 50 mm x 50 mm x 100 laminae device at a production rate of 100,000 units/year using four different microlamination platforms: (a) when separated into patterning, registration and bonding costs; (b) estimated unit cost for four different platforms

There are two primary implications of this cost analysis. First, it appears that the cost drivers in microlamination processes are likely to be on the patterning side. This is primarily due to the fact that bonding processes are typically performed only once per device while patterning processes are required for each individual lamina. Second, a major strategy for reducing costs is therefore to reduce the number of laminae in a particular design (Porter et al. 2002). Consequently, when one thinks of designing MECS devices for cost reduction, the general principle would be to make the device substrates large and few in number. For device configurations that are small, it would make sense to pattern and bond devices in large substrate configurations and die cut individual devices after bonding to distribute patterning and bonding costs across multiple devices. In this sense, the economics of microlamination are similar to those in the IC industry following the trend toward increasingly larger substrate sizes. In a little more than ten years of MECS device fabrication, already device sizes in excess of 70 cm have been proposed compared with IC fabrication where it took more than 40 years to get over 30 cm. The continued development of high production volume processes for fabricating larger and larger device sizes will become increasingly more important.

As suggested, one promising avenue for addressing the economical production of metal MECS devices is the application of SMT (Sharma and Paul 2003). SMT is the practice and method of attaching leaded and non-leaded electrical components to the surface of conductive patterns in the electronic assembly industry. In addition to being an efficient, economical platform for creating solder joints, SMT also provides a platform for integrating electronics into MECS devices. This factor may become more critical as the need to integrate sensors and actuators within MECS devices grows. The bonding process in SMT requires a low temperature of about 300oC and occurs at atmospheric pressure. The reflow process takes 2-3 minutes, which is negligible when compared to techniques like diffusion bonding which takes hours to bond laminae. The printing and reflow processes can be easily automated as well. Finally, the low fabrication temperatures and pressures offered by surface mount technology will help to minimise warpage and residual stress in materials leading to better process control and more sophisticated geometries.

Was this article helpful?

0 0
Brain Blaster

Brain Blaster

Have you ever been envious of people who seem to have no end of clever ideas, who are able to think quickly in any situation, or who seem to have flawless memories? Could it be that they're just born smarter or quicker than the rest of us? Or are there some secrets that they might know that we don't?

Get My Free Ebook


Post a comment