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Trends in Miniaturization
December 31, 1969 |Estimated reading time: 9 minutes
Product designers increasingly specify smaller components to achieve more board density and provide more product functionality. The upswing of 0201 component use offers a dramatic impact on PCB real estate and allows new investment opportunities for manufacturers previously unable to capitalize on miniaturization trends.
By Dean Casto and Jordan Merhib
The demand for 0201 components is on a steep upward curve. For example, by 2003 it is projected that more than one billion cell phones, containing over twenty billion 0201 components, will have been manufactured worldwide. Additional manufacturers will be needed to meet this enormous demand, and accompanying changes in the equipment market may allow those who could not previously invest in high-density components the opportunity to do so.
Increasing Complexity, Decreasing SpaceThe trend among product designers is to specify smaller components, thereby increasing density, decreasing board size and improving product functionality. This is happening among a wide variety of products. Personal digital assistants (PDA) now surf the Web and have cell phone capabilities. Digital cameras are smaller yet offer sharper photos and more memory; even toys are using more advanced chip design and technology.
As a result of this trend, 0201s are likely to become the solution-of-choice for numerous consumer electronics because they offer dramatic improvements in product miniaturization and functionality. Generally, when moving from the 0603 to the 0402 component, the package size is reduced by 64 percent. If 0.15 spacing is used, a 67 percent reduction in size can be realized. Yet 0201s offer even more significant size savings, as they can reduce the typical cell phone board by more than 50 percent without changing the board design (Figure 1).
0201 Production TrendsThe high level of functionality required for Internet-ready cell phones is pushing component spacing to ever-tighter levels. Figure 2 illustrates an increase of 6,500,000 in 0201 placements between April 1999 and April 2000 (from 500,000 to 7,000,000) for just one voltage controlled oscillator (VCO) manufacturer. In current production, some manufacturers are achieving good results with product designs that use spacing as close as 0.15 mm. The Create Group of Panasonic is an equipment supplier helping manufacturers achieve optimal results by achieving spacing as close as 0.12 mm. The multifunctional cell phone devices and system in package (SiP) typically use a more stable substrate that will allow the tighter parameters of 0.12 mm spacing.
Component Miniaturization TrendsIt is clear that the projected increase in cell phones, PDAs and digital cameras will increase the demand for printed circuit board (PCB) miniaturization and smaller components. What may not be so obvious is the potential breadth of demand for miniaturization (including 0402s) across other industries, and the extremely accelerated pace of that demand. For instance, the Wall Street Journal indicated in a December 2000 article, "electronic toys, in particular, are in critically short supply. The scarcity is not necessarily because of big demand (for toys) ... instead, a chip shortage in Asia has delayed shipments." As the scope of miniaturization reaches broader markets and the demand for 0402s and 0201s increases as a result, additional manufacturers with the capability to handle high-density components will be required to fill these expanding markets.
Figure 1. 0.15 mm component spacing using 0201/0204 vs. 0402/0603 using 0.3 mm spacing test board.
Process Design vs. Product DesignProduct design, with its demands for increased functionality and miniaturization, traditionally has driven design trends. Today, the electronics manufacturing industry is becoming more sophisticated. Market leaders in 2001 will bypass product design demands and focus on process design to achieve innovation and technology gains.
That trend to process design is revolutionizing the use of 0201s. Instead of a reactionary approach incorporating 0201s in PCB assembly PCB manufacturers increasingly are adopting a more proactive approach to 0201 integration. They evaluate the entire process by its long-term viability rather than its short-term adaptation of a specific 0201 application.
Success by StrategyIncreased attention to the process design also means that more attention may be paid to the big picture, such as controlling parts per million errors and maximizing accuracy and reliability, which could lead to increased profitability. To achieve this end, contract manufacturers (CM) must give strategic consideration to the overall requirements involved in 0201 placement, such as PCB design, screen printing, placement, reflow and test, and inspection.
This is critical, as the process is just as important as the product design, but often has been overlooked. Both current and future 0201 users will be challenged with achieving the complex parameters necessary for optimum 0201 placement, while weighing profit factors such as error rates.
Challenges in Adopting 0201 CapabilityKnowledge Acquisition. CMs often have timetable delivery schedules that limit their ability to investigate the viability of pursuing high-density work. They need to evaluate what constitutes a minimal investment, and the kind of costs, error rates and profitability figures to expect. Following are some basic timesaving solutions to this dilemma:
- To get a jump-start on the learning curve, make inroads with equipment suppliers who have a concentrated focus in electronics miniaturization and real production experience.
- Minimize the risk of new technology adoption by working with companies that already have used 0201s, cleared the hurdles of process improvement, and can provide the research and development (R&D) resources to help implement an appropriate strategy in the high-density market.
The best return on investment starts not by paying for a partner's learning curve, but by leveraging a partner's knowledge for market advantage.
Figure 2. One VCO manufacturer's ramp up from 500,000 to 7 million high-density placements from April 1999 to April 2000.
Equipment Acquisition. The PCB assembly market traditionally has been segmented into different levels, or tiers of suppliers. The level of financial commitment has escalated with each tier and level of sophistication. In 2001, this is predicted to change because the equipment market will be reinvented. Demand is increasing, technology is more accessible and the market is opening up to nontraditional, non-tier relationships. OEMs and CMs previously unable to commit fiscally to the high-density market will find new options and resources available to them, as having 0201 placement capability quickly is becoming a point of differentiation and a competitive advantage.
Challenges in Increasing 0201 CapabilityComponents and Pick Quality. Component manufacturers are responding to demands to improve quality in order to reduce the number of miss picks. Studies on pick-up miss rates involving 0201 components, equipment, operator influence and programming have pinpointed some of the miss rate causes to the chips themselves and the carrier tape.
When focusing on the 0201 component, the critical parameters include the shape, (length, width and squareness) and surface (irregularities in electrodes). The carrier also is an important factor in miss rates and different facets, such as the top tape and carrier tape, need to be looked at critically. The Create team, in conjunction with their factory in Japan, has made a number of recommendations regarding component dimensions and carrier tape tolerances (Figures 3a and b).
Figure 3. It has been determined that the pocket clearance of 0.035 mm will provide a stable pick up. (Recommendation includes reducing F from °0.1 mm to °0.05 mm.) The challenge is for component manufacturers and tape suppliers to provide a consistent product. (a) Graphical representation of component spacing A, B, D and F. (b)
New Developments in 0201 Pick-and-place Specifications. To improve quality, the pick-up mechanism requires close inspection of the chip's relative position to the nozzle as well as pick-up force and speed. Tests used a 0.1 second tact time (36,000 cph). Pick-up errors during the testing could be attributed to deviations in X, Y and Z. In an effort to further define 0201 placement specifications, the following criteria were tested: deviations in the X-axis greater than 0.15 mm (0.006"), in the Y-axis greater than 0.075 mm (0.003") and control of the Z-axis from 0 to 0.15 mm (0.006").
To ensure a proper pick procedure without damaging the component and to allow the proper vision inspection of the component, the following specifications have been defined:
- Repeatability in X and Y axis of °0.02 mm
- Pick-up compensation in X and Y by the equipment
- Controlled height of each feeder slot
- Tape feeding accuracy of °0.05 mm.
A key element in the pick-up mechanism is the Z-axis control coupled with the feeder height. To improve pick-up of these low-mass components and avoid damaging them, testing has proven it prudent to program a "pick gap" at the tape feeder. This is a gap between the nozzle and the top of the component (component in the pocket). The process requires using a method that "suctions" the part out of the pocket for a more reliable pick-up.
New Developments in 0201 Mounting Specifications. As the trend for higher density component placement is pushing the spacing standard to 0.15 mm, pick-and-place equipment used for 0201s is being challenged to deliver increasingly tighter tolerances in a real world production environment. To achieve this new 0201 spacing standard of 0.15 mm, pick-and-place equipment must maintain an accuracy level of 0.05 mm at 3 S with a process capability (CPk) more than 1.5, and 0.1 mm at 6 S with a CPk at 1.67 or better.
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Focusing on New 0201 Equipment. This should begin by evaluating a supplier's commitment to the high-density industry. Equipment should be specifically designed for, not just adapted to, PCB miniaturization. A machine that can handle board sizes greater than 18 x 20 and place 0201s should raise inquiry. The supplier should have machines currently in production using 0201s.
When evaluating equipment capabilities, it is important to realize that a demonstration on double-sided tape does not represent a real-world production environment and, therefore, is not an adequate showing of equipment competence. With double-sided tape, the nozzle interference on neighboring chips cannot be identified or evaluated. Nozzle interference can be a significant cause of placement errors. A minimal nozzle size and profile will offer the most accurate placement without interference, and allow for increased spacing flexibility.
There are several other critical factors to consider: pick-up reliability and concerns in taping, component size and shape, and the machine's ability to pick without damage from the feeder and vision inspection equipment. Once picked, component spacing plays a large part in product quality. The equipment must be capable of accurately placing an 0201 component with precise 0.15 mm spacing, as this quickly is becoming a key industry requirement.
As 0201s are specified in a wider range of products, component spacing also will become a point of differentiation among CMs. Primarily, this is because the driving factor in miniaturization and high-density manufacturing is size reduction either to accommodate additional functionality, reduce the overall size of the end product or both. These objectives cannot be realized effectively if, for instance, 0201s are placed with the spacing parameters of 0402s.
Capturing Trends for Market Opportunities. A long-term investment in equipment should be determined by anticipated needs whether it can meet the requirements of future demand. The trend to reduce size, with increased functionality in PCBs, likely will remain at the top of market demands and industry trends and likely will offer CMs an increasingly profitable market opportunity. As industry shifts focus from product to process design, technology acquisition costs will decrease. CMs who could not afford to compete previously will have new opportunities in which to capitalize on miniaturization trends.
JORDAN MERHIB, national sales manager, and DEAN CASTO, sales administration manager, can be reached at Panasonic's Create Group, 9377 W. Grand Ave., Franklin Park, IL 60131; (847) 288-4487 or (847) 288-4263; E-mail: jmerhib@panasonicfa.com and dcasto@panasonicfa.com.