If you have been looking for reliable, dependable sources of silicon interposers in anything beyond prototype quantities – like I have the past few years working with DoD programs – then you know that in the U.S there just aren’t any such sources.
Those of you that have been around our industry awhile, like I have, remember GlobalFoundries (GF) working on silicon interposers around 2013-2015, built on a 65nm manufacturing flow. They gave presentations at several conferences at the time but then seemed to go into hibernation. Rumors circulated that GF would only supply silicon interposers for customers for which they were manufacturing the chips that would be assembled on these interposers.
In this exclusive interview with Greg Kleese (GK), GF Aerospace and Defense Business Line Director, IFTLE got some direct answers about where GF stands on these issues.
IFTLE: Is the 2013-2015 (65nm) technology still the technology that is being used by GF for silicon interposers today?
GK: Yes it is … the process is known as 65PKG. The technology is capable of three or four layers of 1.2 µm thick copper (Cu), minimum critical dimension (CD) 0.8µm, with vias between layers at 1.6µm. We offer 10µm x 100µm through silicon vias (TSVs) suitable for signal, power and ground. The design package design kit (PDK) is available on GF’s customer portal, accessible from gf.com. With a suitable NDA in place, and export compliance requirements met, customers can access and begin design immediately. We manufacture the 65PKG interposers at our facility in Malta, NY, and can produce for designs requiring strict export controls (such as ITAR) and Trusted, as needed.
IFTLE: What is the technology readiness level (TRL) and manufacturing readiness level (MRL) of current technology?
GK: The 65PKG is production qualified, which is TRL9. Fabrication is performed at GF’s Malta NY fab.
IFTLE: In the past, it was rumored that GF was only willing to consider manufacturing Si interposers for customers if the chips on the module were being manufactured by GF. Is GF now reconsidering that position?
GK: GF now places no restrictions on foundry origin of die to be mounted on 65PKG. Our 65PKG interposer is now available for design and shipment to all customers around the globe.
FYI … GF produces a variety of full-featured essential technology platforms. Bulk CMOS, FinFET, FD-SOI, SiPh, RF SOI, SiGe, BCD and GaN. Our breadth of offerings provides for an unmatched tool kit for a chiplet 2.5/3D system solution. GF technologies enable customer solutions for improved size, weight, power and cost (SWaP C).
IFTLE: If a customer comes to GF with a 2.5D module design containing a mixture of GF manufactured chips and non-GF manufactured chips will GF take such an order?
GK: Yes…Customers can execute a design on 65PKG that will serve as an interposer for both GF die and die from other foundries.
IFTLE: Will GF require that they oversee the assembly, or will they allow the customer to choose the OSAT used for assembly?
GK: GF offers turnkey post-fab services that include our 65PKG interposer offering. Alternatively, we can ship completed wafers, or sawn interposer die directly to customers. Our flexible manufacturing services are designed to seamlessly progress customers from chip design, through wafer fabrication to final assembly. The aggregation of these offerings results in a stronger supply chain, a more resilient ecosystem, and faster time to market for our customers.
IFTLE: If a customer came to GF with all non-GF manufactured chips or chiplets to be assembled on a silicon interposer would GF consider such an interposer order if they were only manufacturing the silicon interposer?
GK: The customer would implement their design on 65PKG using GF PDK and industry standard EDA tools. GF has strong OSAT networks and alliances in the US, EU and Asia. In the case of an interposer-only purchase we can provide guidance and contact information into our preferred OSAT supplier base.
IFTLE: Is GF currently considering taking silicon interposer orders from typical DoD suppliers who would need typical DoD “low-volume / high-mix” production runs?
GK: Yes, certainly we support DoD business from the lowest volumes to the highest volumes on our current base 65PKG process. We can provide for low-quantity orders, with a minimum of three wafers. This range in scale is a key differentiator for our aerospace and defense business. Whether a customer needs 3 wafers or 30,000 wafers we can support it.
IFTLE: With what appears to be renewed interest by GF in silicon interposer fabrication, will we be seeing advanced interposer technologies appearing on the GF roadmap?
GK: GF is presently conducting market research to determine technical requirements and business demand for an expanded interposer roadmap. Deep trench and MIM capacitors, integrated passives, integrated active devices, and increased metal layers are items already identified as possibilities. We welcome additional inquiries and engagements from our customers to feed this roadmap development investigation.
IFTLE: Who should potential customers contact to discuss potential business scenarios?
GK: Commercial / consumer customers should directly contact their GF Account Manager. Aerospace, Defense and critical infrastructure customers can contact me directly: greg.kleese@globalfoundries.com.
For all the latest in Advanced Packaging stay linked to IFTLE………………………….
