How the roadblocks to making 450 mm a reality can be solved.
Facility Considerations for the 450 mm Transition
Allen Ware, Don Yeaman
M+W U.S., Inc. - A Company of the M+W Group
Making 450 mm a reality is not only a monumental task from a technical and manufacturing standpoint, but as we consider the facility infrastructure, it becomes apparent that merely scaling the new facility is not a practical option. The size of the 450 mm facility infrastructure and associated utility consumption projections will simply exceed affordability realities or resource availability.
These roadblocks can be addressed only through solutions developed in collaboration with facility experts across the entire supply chain. M+W Group, as a leading design-builder of technical facilities, in consultation with Global 450 mm Consortium (G450C), is coordinating with select semiconductor facility companies around the globe to bring their collective expertise to bear on the most pressing facility issues. These collective companies form the Facility 450 mm Consortium (F450C).
Through a series of G450C member workshops, experts from member and associate companies will join forces to identify viable solutions in time to intercept 450 mm high-volume manufacturing (HVM) facility construction. Two initial focus areas are reducing tool install cost and duration; and improving facility sustainability.
A specific tool install opportunity is the implementation of 3D templates (or adaptor plates) to allow pre-facilitation ahead of tool arrival, which reduces install cost and schedule. While 3D templates are not a new concept, fully realizing the potential benefits have proven elusive - related initiatives in the past were often derailed by constant tweaking of the tool design right up to ship date. These ongoing changes then either delayed delivery of the 3D template, resulting in a missed pre-facilitation window, or required extensive rework of any pre-facilitation that had been completed. Over the last several years, a few operational enhancements have converged to boost confidence this time around. First, leading tool vendors are now designing their tools and support equipment with fewer points of connection, along with incorporating standardized and integrated component frames. Secondly, member companies are building on this concept and achieving additional cost savings through standardization of mainframe connection types and sizes.
Figure 1. F450C Member Company Logos
Recognizing that every 10 percent increase in power capacity designed into a facility increases base build CAPEX by ˜2 percent, G450C sponsored a sustainability focus to better align installed facility system size with actual system capacity requirements. Unfortunately, the typical exercise to build up facility utility requirements is susceptible to a compounding effect of conservative baseline + cushion + buffer + contingency. Contingencies are commonly introduced by the tool vendors, design teams and the owner. While R&D facilities are intentionally designed to accommodate a large fluctuation in utility requirements, it's reasonable to expect that HVM facility requirements would reflect accurate demand projections based on real data from operating pilot lines. It is well known, for example, that the average operating power consumption for process tools is usually no more than 30 percent of the connected load and thus the Delta-T across the cleanroom recirculation cooling coils ends up being significantly less than the design value. The industry could try to scale known 300 mm power consumption to 450 mm facilities; however, it is unclear whether this benchmark will hold true for the new tools and technologies expected to be deployed in the next-generation facilities.
Figure 2. Diagram of an Adapter Plate
We already recognize that next-generation lithography tools (EUV) will have high power demand, but the average load is not readily apparent. To define realistic facility system demand criteria, we need data derived from the time-weighted averages of tool loads at idle, operating and peak. To help the member companies better understand the true demands of these 450 mm tools, G450C is planning to install measuring devices on the critical 450 mm tools to record idle, peak and average flow rates. These accurate baseline measurements will allow member companies to optimally size HVM facilities with reasonable and intended contingency.
Evolving eco-friendly mandates call for innovations that reduce energy and water consumption, and minimize generation of waste throughout the facility life cycle. It's no longer just a matter of complying with minimal EPA requirements and then going further only when there is a return on investment. Companies are now responding to public expectations and recognizing their responsibility as good corporate neighbors.
Using water as a case in point, during the 200 mm to 300 mm transition, the amount of UPW consumed per wafer pass in the batch wet tools remained relatively constant due to a simultaneous decrease in wafer pitch in the wet sink carriers. This opportunity to pack more wafers closer together in the batch wet tools as we transition from 300 mm to 450 mm does not exist. Therefore, it is likely that the UPW consumption of a batch wet tool will scale with the wafer surface area (225 percent). It is also expected that as we transition to 450 mm, more wet process steps will move from these batch tools to single wafer systems. This will result in an additional increase in water usage, since UPW consumption (per wafer pass) for single wafer tools is higher than their batch counterparts.
The yield benefits of single spray are compelling, but the related water requirements for newer 450 mm factories will likely overwhelm existing municipal infrastructure or cause a public outcry that has the potential to further complicate permitting and customary incentives. Since only a portion of the water intake is actually consumed (˜20 percent), a pragmatic solution is to reuse/recycle. In water-constrained areas of the world, we've already achieved reuse/recycle rates exceeding 80 percent. The challenge is to develop water treatment systems that are cost-effective and that do not introduce unreasonable risk into the manufacturing process. Without a viable path forward on water use reduction, device manufacturers will not only significantly limit future facility location options, but they may also constrain expansion at many current locations as water demand exceeds availability.
Figure 3. Wafer Clean
For construction professionals, 450 mm facilities will bring new challenges related to project logistics. Time-to-market schedules that compress ever-more complex construction activities on a relatively small footprint require extensive space management, crane management, ingress/egress planning and layout area ingenuity. A compounding challenge is that emerging facility capacities will drive pipe/duct sizes exceeding traditional transport configurations, requiring transport of smaller component sections that must be assembled on-site by specialized contractors. Traditional construction techniques will exceed local trade availability and reasonable body per square foot stacking. The ideal solution is to move more fabrication to offsite locations.
Figure 4. F450C Charter
In response, design and construction firms are quickly embracing extensive 3D modeling that continually adapts to a precise knowledge of current on-site conditions. Most construction tolerances in place today are greater than the variations required for prefabrication. To maximize the use of offsite prefabrication, real-time as-built conditions must be captured and disseminated to off-site shops for just-in-time assembly and delivery. While an obvious benefit of prefabrication is the interchange from on-site labor to capable and lower-cost offsite resources, another advantage is that off-site fabrication facilities are optimized for assembly efficiency, quality control and worker safety. All in all, off-site prefabrication and modularization enable "Lego-style" assembly of precision components that take full advantage of transportable size limits and save time and money along the entire supply chain.
Safe work environments and employee well-being are an intrinsic part of F450C member-company culture and values. As such, F450C is proactively addressing the safety posture of this next generation of facilities where we will see bigger tools with awkward access angles to reach and remove heavier tool components. With these specific risks in mind, there is early focus on considering fall protection and ergonomics. For fall protection, we are developing standard fixtures that can be incorporated either into the process tool itself and/or into the cleanroom ceiling system that would improve working at height safety. As we look to worker ergonomics, we envision common solutions for moving and handling large and heavy process-tool components (e.g., vacuum chamber lids). Potential options include tool-mounted, floor-mounted, ceiling-mounted, and mobile hoists and lifts. Related to this topic, G450C will seek member alignment on aisle/chase/bay dimension for safe access and movement of tools and tool components.
Semiconductor technology innovations and the associated 450 mm wafer size evolution are as much a certainty as the growing assimilation of the WEB into daily life. While many debate the timing of the 450 mm transition, few deny the inevitability. The G450C companies have embraced the task with their eyes open to the sensitivities of standardized solutions in an intensely competitive and a seemingly IP-paranoid industry. The G450C cooperative model recognizes the prerequisite basic-level industry alignment and cost sharing as an enabler to individual company success. Beyond the manufacturing hurdles, the industry understands that 450 mm facility challenges require collaboration across the entire supply chain. The F450C partnership with G450C brings in the critical facility expertise needed to define pre-competitive facility solutions enabling the 450 mm evolution.
About the Authors
Allen Ware is vice president, program executive for the Facility 450 mm Consortium. He has been with M+W U.S. for approximately two years, following 14 years at Intel, where he managed facility CAPEX procurement. He is a retired Lt. Col. in the U.S. Army Corps of Engineers.
Don Yeaman is director of technology. He has more than 30 years of experience in advanced tech manufacturing, fab design and construction for both research & development and manufacturing facilities. He has worked for M+W U.S. for more than 16 years.