Developments in Advanced Packaging Lithography: Q&A with Rudolph Technologies

Developments in Advanced Packaging Lithography: Q&A with Rudolph Technologies

Ardy JohnsonRudolph’s marketing vice president, Ardy Johnson, answers SEMI questions about recent developments in advanced packaging lithography and explains the company’s strategy in entering the market.

SEMI: What are the important customer requirements in Advanced Packaging lithography?

Johnson: Advanced packaging (AP) requires emerging capabilities from steppers to accommodate the needed design changes demanded by new technologies such as TSV, eWLB, silicon and glass interposers and other advanced wafer-level packaging solutions now being developed. In addition to the need for higher resolution as the package features follow an inevitable trend to smaller sizes, challenges include wafer flatness, automated partial field exposures and large, non-standard substrate shapes and sizes.

At a higher level, as their processes become more expensive and more complex, advanced package manufacturers are increasingly adopting process control and yield improvement strategies from the front end.  Both semiconductor manufacturers and OSAT providers need partners that deliver leading-edge, back-end technology along with complete process solutions. Specifically, the advanced packaging market needs a stepper supplier willing to be flexible and capable of delivering unique solutions for their requirements, and a process control partner that can deliver improved production systems for advanced packaging applications.

SEMI: How big is the market?

Johnson: Advanced packaging is in the early stages of dynamic growth.  According to SEMI, the Test, Assembly and Packaging equipment market is expected to increase 10 percent in 2014.  Even though the market for new Assembly and Packaging equipment is expected to contract in 2012 and 2013, the amount invested in (this segment) is expected to remain above the average spent from 1997 through 2011 (~$2.3 billion per year), averaging $3.1 billion between 2012 and 2014, a 38 percent increase over historical level.

Yole Développement has forecast demand for equipment and related tools in the 3D-IC and wafer-level packaging area to grow from approximately $370 million in 2010 to over $2.5 billion by 2016, a CAGR of 38 percent over that period. 

Gartner has predicted the wafer-level packaging equipment market will accelerate through their 2016 forecast period with increased use of bumping, WLP and through-silicon-via (TSV) processes. We believe that their estimates are conservative and that the forecasted growth of the advanced packaging market will be significant. 

SEMI: What are the key technical trends and challenges in this area?

Johnson: Many of these processes are still in development and new processes will certainly emerge. In general we expect several trends apparent now to continue as the processes and market mature. Increasing structural complexity and decreasing feature size will require higher resolution optics, more precise alignment and larger, more expensive mask sets. The three-dimensional nature and increased topography of many AP structures will require larger depth of focus in each exposure. Warped wafers will require special handling capabilities and adjustments to z and tilt before each exposure. Larger substrates in various shapes will require fast, flexible handling and will bring pressure to increase field size in order to maintain throughput. Large assembly and test operations handling a wide variety of products and designs will require the ability to quickly and easily change stepper configuration. As AP processes become more complex and more capital intensive they will require increasing attention to process control and yield management.

SEMI: What other applications/markets can this technology serve?

Johnson: Flat Panel Display is a market that we will continue to participate in. The flat panel industry has had a challenging couple of years, however forecasts show the flat panel market starting to rebound in the latter part of 2013 and we’d certainly expect to be a solid participant in the upturn, when it comes.  We expect to immediately begin discussing with FPD customers some of our yield enhancement solutions to further differentiate our display products as we await market recovery.  Flat panel is what we like to call “icing on the cake” — business that is on the horizon and affording us a very nice upside. 

SEMI: Why did Rudolph enter the market through the acquisition of Azores?

Johnson: By leveraging R&D investments from both the Rudolph and Azores organizations, we took a field-proven 2X display lithography technology widely used in the flat panel industry, and applied it to the needs of the high-growth back-end packaging market where Rudolph already has long-standing customer relationships and global brand recognition.

SEMI: What unique capabilities does Azores provide to the market?

Johnson: Key JetStep System advantages include the largest printable field-of-view to lower cost of ownership; programmable aperture blades and a large on-tool reticle library for ease of use; quick change to lower reticle cost management for high product mix operations such as OSATs; large depth-of-focus to accommodate 3D structures in advanced packaging; autofocus, large working distance, and warped wafer handling to accommodate the highly warped wafers prevalent in today’s advanced packaging process; and low cost of consumables. In addition, a number of packaging technologies are looking to panel sized formats to achieve cost reduction through economies of scale — examples are fan-out wafer level packaging, and interposers. The JetStep is capable of addressing these larger-sized substrates without significant changes to hardware design.

SEMI: What capabilities does Rudolph offer Azores? 

Johnson: Rudolph’s total lithography system now includes:  the JetStep 2X reduction stepper integrated with Rudolph’s equipment automation and fault detection software; the NSX® inspection tool for defect detection and CD overlay measurements; ProcessWORKS® APC software, a comprehensive run-to-run control system and for full, closed-loop control; and the Discover® fabwide yield management system for automated, real-time process control.

Our organization very readily addresses the lithography market and we are highly confident that we will be successful.  A wealth of lithography experience and expertise now resides within Rudolph.  Rudolph has acquired a company with proven stepper technology, a solid patent portfolio, and a team with over 500 man-years of lithography experience that we expect to smoothly integrate into Rudolph’s culture of growth and innovation.  We have a number of team members with 20+ years of experience.

We are process control experts.  Rudolph “surrounds” the advanced packaging litho process with our process control solutions including inspection, metrology and software.  In a typical TSV pillar bump process, Rudolph may touch the wafer as many as 114 times. We know and understand each process extremely well.  We have over 40,000 installations, and years of experience supporting processes with our ControlWORKS®, ProcessWORKS and Discover Enterprise software solutions.  We have over 1,000 inspection tools supporting back end applications and over 1,000 wafer handling systems supporting the unique substrate handling requirements of the back end.


Ardy Johnson is currently VP of Marketing at Rudolph Technologies. In this capacity, he oversees the Product Management, Communications, Strategic Market Research and Process Applications groups. Johnson held this same position at August Technology before its merger with Rudolph in 2006. Prior to his tenure with August, Johnson was employed at FSI International, Inc. for 25 years, serving most recently as VP of the Microlithography Business. Johnson has a B.S. degree from the University of Minnesota and an M.S. degree from the University of Wisconsin.

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February 5, 2013