At Alchimer, we believe that as it becomes technically more difficult to shrink to further nodes, companies will turn to 3D technologies to achieve the performance requirements of next-generation computing needs. We expect that to happen at 7nm node, when 3D will be cost competitive with scaling. In 2014, we expect to see the industry begin ramping to 3D, while at the same time, work continues to optimize technologies for improved yield and reduced cost of 3D TSVs.
We believe adoption of Alchimer’s electrografting processes for TSV metalization can greatly impact the roadmap for high-volume manufacturing in several ways.
First is cost. While several foundries have TSV lines in place, production is low because of process cost. We believe our electrografting processes for TSV metalization offer a considerable cost reduction when compared with the electrochemical deposition (ECD), chemical vapor deposition (CVD) and physical vapor deposition (PVD) processes currently used to plate TSVs. Alchimer’s cost savings comes in the form of a reduction in cost of consumables required, as well as using lower-cost equipment that requires a smaller footprint than ECD and CVD tools, thereby reducing cleanroom and labor costs.
On the technology side, Alchimer’s three-layer solution for insulation barrier and seed layers can achieve higher-aspect-ratio (HAR) TSVs than conventional processes. Alchimer’s electrografting creates a chemical link via a covalent bond between the substrate surface and the coating, which allows for a buildup process rather than a deposition, creating much more control over conformal thickness.
Alchimer recently demonstrated 40:1 aspect ratio vias with electrografted insulation, barrier and seed steps, and 20:1 for the fill step. In addition to offering a cost reduction by enabling TSV scaling, the ability to create HAR vias also provides a solution to the thin-wafer handling issue, because the wafer can be thicker with the same diameter via and increased via depth. Working with thicker wafers eliminates the need for temporary bond and debond, eliminating steps and simplifying the process flow. We believe if customers adopt Alchimer’s technology, it will affect the ramp to high-volume manufacturing.
Conversely, moving to a smaller-diameter via increases density. Simulations shows that it’s better to have several single vias instead of one big one for reduced thermomechanical stress, improved signal integrity and efficient use of on-chip real estate. In either case, Alchimer’s technology can achieve higher aspect ratio than competing approaches, helping customers improve yields as well as meet the challenges and specifications of 2.5D and 3D integration technologies.