by Françoise von Trapp, managing editor, Advanced Packaging
June 11, 2008 — Replisaurus has maintained a low profile since announcing their first round of funding in August 2006, but there has been a lot going on for the start-up company. With last week’s announcement of the company’s acquisition of Smart Equipment Technologies (SET), the company is ready show the world what it’s been up to.
“What we wanted to do was avoid going out and creating lots of hype about our technology while it was being developed,” explained CEO Jim Quinn, in an interview. “Now it’s time to start being more visible.”
Replisaurus has developed a proprietary process called electrochemical pattern replication (ECPR) which Quinn calls a “middle of the line” process, bridging the gap between front- and backend processes. “It can run metallization for wafer-level packaging, or go below the passivation layer,” he explained. This metallization transfer process eliminates lithography and photoresists, reducing traditional eight-step lithography metallization down to three steps, the company claims [see Figures 1-2]. In the first step, a master wafer patterned with insulating material and pre-filled with copper is aligned with the target wafer, which is flooded with electrolyte. In the contact mode, the two wafers are joined and current is applied to the master wafer which ionizes the copper and transfers it to the target wafer. After the metal transfer, the master and substrate are separated and the replication is complete. In production, all three steps — fill, transfer and clean — are performed in parallel.
With ECPR, traditional eight-step lithography based metallization…
“This is a completely fab-friendly, environmentally clean process,” said Quinn. He added that ECPR redefines metallization by reducing a one-hour process to five minutes, reducing the eight steps to three (requiring one tool vs. six, with no solvents or developers), and removes cost and complexity from conventional processes.
…is reduced to three-step direct metallization. (Source: Replisaurus)
Initially, the technology will target wafer level packaging applications such as creating the redistribution layer (RDL) for integrated passives, achieving ultra-fine pitch copper pillars, and via filling for 3D integration. And that’s where SET comes in. “Start-ups are needed to develop technology,” noted Quinn, “but you need the infrastructure of an established equipment company to roll out the product.” Initially, the company purchased a tool from what was then Suss MicroTec France and retrofitted it with their chamber that runs the ECPR process. The Titan, originally developed for copper-to-copper bonding, became the Pattern Replication Aligner. Thus, Suss became their equipment supplier, which gave Replisaurus a headstart as they wouldn’t have to develop a tool from scratch.
According to Quinn, the decision to acquire SET came after last year’s management buyout, when Gaël Schmidt, managing director and president of SET bought Suss MicroTec’s die bonder division. Concerned about the impact it might have on Replisaurus, the natural progression was to acquire the company. SET’s product portfolio comprises a device bonder, a chip-to-wafer bonder, a nanoimprint lithography station, and now the pattern replication aligner. SET is a wholly-owned subsidiary of Replisaurus, with both companies managing their own divisions and operating from France and Sweden, respectively. Although no final decision has been made, Quinn noted that both brands will be optimized to promote their strengths.
While SET’s products continue to be marketed, the ECPR has reached first demo stage (1-2 and 20 wafers of 1- and multilayer), and plans to engage customers in extended demos by 2009 (20 wafers both 1- and multilayer, in production runs of 10-20 batches of 250-500 wafers). First tools are expected in the market by 2010, with pilot production extending the demos with several more batches. F.v.T.