Sandwich process puts chips inside the PCB
A Finnish company aims to slash the size of portable electronic devices by putting the chips they use inside the printed circuit board (PCB). Imbera has developed a manufacturing process that allows chips and other electronic components to be sandwiched between the layers of a PCB, allowing other devices to be stacked on top.
Jeff Baloun, CEO of Imbera, said it should be possible to realise space savings of up to 40 per cent by moving to the company’s system-in-board technology. The company is setting up high-volume manufacturing in Asia to produce the sandwiched boards. Baloun said the company has a telecom customer looking to use the process.
Risto Tuominen, CTO of Imbera, said the company was originally spun out of university research into techniques to embed devices into PCB but that Imbera has extensively reworked the technology to come up with its latest process.
“The yield and cost are the important things. One of the advantages of this process is that we are using standard materials and processes for the embedding. We use a normal flip-chip or chip-shooter machine to place the components,” Tuominen explained, noting that flip-chip devices can use conventional solder bumps to form the connections between the chip and board circuit traces, as with a conventional PCB manufacturing process. “We have simply mixed up the ordering a little. Instead of putting components on top, we put them inside.”
Placing devices inside the PCB can help with cooling, Tuominen added, as heat conductors can form part of the sandwich. “When customers approach us they have the reduction in size as the key driver in their heads. But they find other features, such as the thermal properties.”
Imbera started with a business model to licence the embedding process, which can be used to produce embedded PCBs and system-in-package modules, but decided to concentrate on manufacturing. The ultimate aim is to produce completed boards but the initial line will provide embedded boards and packages that can then be transferred to other electronics assembly companies. The biggest difference between Imbera’s PCBs and conventional PCBs is the need to have much tighter control over static discharges to prevent the active devices from being damaged.