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ECPR for short
January 6, 2008
Hope everyone has had a great holiday season, I know I did since I got to spend a week with my granddaughter Hannah in TX.
To start off 2008, I thought I would discuss a few “Leading Edge” technologies that could be of interest to you. The first is “Electrochemical Pattern Replication” or ECPR for short which is being developed by Replisaurus.
Replisaurus Technologies was founded in 2003 near Stockholm. In the summer of 2006 Replisaurus raised a $14 MM first round of funding led by Wellington Partners and Northzone Ventures. They have been involved in technical collaborations with the Royal Institute of Technology (KTH), IMEC and Acreo (a Swedish R&D house) to develop their technology. Their initial IP can be found here: [ WO/2002/103085 - Method and electrode for defining and replicating structures in conducting materials ]. In 2005 they were listed in the EE Times emerging startups “Silicon 60” list.
ECPR is a nanoscale electrochemical deposition technique utilizing a reusable master electrode as a template to fabricate metal patterns in a single replication step. ECPR is similar to nanoimprint methods since it is based on replication from a relief template, but different in that it enables direct replication of metal patterns by means of electrochemical deposition.
In the ECPR process (shown below) , a template (“master electrode") consisting of an electrically conducting electrode layer and one or more patterned layers of electrically insulating materials, is gently pressed against a substrate with an electrolyte applied between the two surfaces (step 1). When put in contact, excessive electrolyte is forced away from the master electrode / substrate interface and local electrochemical micro cells, filled with electrolyte, are formed (step 2). When an external potential is applied between the master electrode and substrate surfaces, electrochemical material transfer takes place inside each local electrochemical cell. Solid metal is dissolved at the anode and transported through the electrolyte in each micro cell and deposited on the cathode (step 3). The master electrode is then withdrawn and the Cu seed layer is chemically etched away to leave the desired pattern (step 4).
Predeposition of anode material is done prior to each plating cycle. Predeposition of metal in the “master electrode” and ECPR transfer to the substrate are done on the same tool.
The full process sequence is thus :
- seed deposition on the substrate
- predeposition of metal in the master electrode
- ECPR transfer of the metal from the master to the substrate
- Seed layer etch on the substrate
The basic idea of the ECPR concept is to enable reuse of the pattern defining insulating structures on the master electrode for many substrates instead of defining the pattern in a photoresist template on each substrate prior to metallization, which is the case for traditional lithography based processes.
Replisaurus reports that ECPR can transfer copper at 4 µm/min. Thus, the cycle time for producing 20 µm copper patterns would be 5 minutes plus handling time, which they report is significantly lower than the cycle time that can be achieved by standard pattern and plate processes.
To enable a conformal contact over the entire surface, the master electrode structure must be able to compensate for substrate roughness between the surfaces and still give a well defined contact pattern, the same as for micro contact printing.
As of August 2006 we have not seen or heard much from Replisaurus who has been in the stealth mode, tending to their knitting , so to speak. Jim Quinn their CEO explained to me recently that they needed to “... grow their staff and focus on proving out the technology on real IC and packaging topography”, which they feel they have now done.
Their business plan is to supply customers “....the tool, the masters and the full process from Replisaurus.” Their expanded engineering staff will be doing tech transfer at the customer site and qualifying the process with them. Replisaurus will then continue to supply the masters for their customers commercial production.
They report being able to reproducibly print (metallize ) submicron Cu traces over 150 to 300 mm wafers. Their application sweet spots continue to look like they are: thin film passive integration (see inductor coil below); redistribution, via filling and copper pillar bumps. They are intrigued that that 3D TSV technology appears to be gated by copper deposition technology and will soon be taking a look at their fit in this expanding market segment.
Replisaurus has been working with a major industry player (as yet un-named) on their technology development. Quinn indicates that they will be making some major announcements in about 6 months, possibly at Semicon West next summer.
If metal deposition is an important part of your process, keep on the look out for coming Replisaurus announcements and remember you heard it here first at “Perspectives from the Leading Edge”
In my next blog we will be looking at Semprius Inc a Research Triangle Park startup which “transfer prints” silicon. Their massively parallel “pick & place” technology is the first truly unique approach I’ve seen in the mature assembly technology segment, in decades....................
Posted by Philip Garrou on January 6, 2008 | Comments (0)
