Robotics in Electronics
by Bennett Brumson
, Contributing Editor
Robotic Industries Association Posted 06/08/2011
“The ease of use of robotics for electronics and semiconductors has increased tremendously which has subsequently reduced installation times and total cost of implementing robotic solutions,” says Rush LaSelle, Director of Global Sales and Marketing with Adept Technology Inc. (Pleasanton, California) LaSelle and his peers in the robotics industry see more powerful yet less expensive robots proliferating for production of semiconductors and electronics.
Speed, Accuracy, Precision
In most industrial applications, robots facilitate high throughput although parts manipulated in those applications are usually less fragile than those found in the electronics and semiconductor sector. “Components are much smaller than in typical industrial robotic applications, requiring higher precision gripper designs. Because process speeds are usually quite fast, grippers need to handle higher inertia,” professes Christopher Blanchette, FANUC Robotics America Corp.’s (Rochester Hills, Michigan) National Account Manager. “Accuracy is an important element in the electronics industry because the parts are much smaller. Precision of locating, placing and assembling parts is critical.”
Robot manufacturers and peripheral equipment providers developed tools such as vision to support the accuracy requirements in the electronics industry, adds Blanchette. Continuing, Blanchette says adaptive robotics is a necessity in the electronics and semiconductor industry. “Robots pick up and place components into electronic assemblies where the position is not always precisely known or parts cannot be reliably placed without finessing. Adaptive tools such as vision or force control allow the robot to ‘feel’ its way into an assembly, placing parts in a dynamic assembly process.”
Precision is also on the mind of Henry Loos, Controls and Application Engineer with Applied Robotics Inc. (Glenville, New York), who says, “Precision is the primary challenge in electronics and semiconductor applications. Tolerances in electronics assembly are much tighter than other processes such as automotive manufacturing.” The necessity for precision is complicated by the requirement for very high production rates, contends Loos.
Accuracy is the biggest challenge in semiconductor applications, says Kirk Barker, Electronics Product Manager at Maxon Precision Motors Inc. (Fall River, Massachusetts) “Accuracy of a control system is ultimately determined by the quality and amount of information provided by feedback devices and sensors. In semiconductor applications, accuracy is the number one consideration given the importance placed on yield.” Barker sees six areas where end-users and integrators should focus on to improve robotic utility in manufacturing: range of motion and dexterity, reach, accuracy, speed, force compliance and safety.
Speed for the sake of speed is insufficient in semiconductor and electronic applications, points out LaSelle. “In handling semiconductors, the robot must not only be fast but must gently handle wafers to avoid introducing micro-cracks or physically damaging the very thin products.” As semiconductor wafers become thinner, 150 microns or less, LaSelle sees increased damage caused by direct human labor. “The propensity for damage is greatest when labor is applied. As wafer thicknesses decrease over time as forecasted, thermal expansion of the silicon will become an issue during soldering.”
LaSelle goes on to say, “Unlike traditional semiconductor industry pursuits, alternative energy manufacturing processes are early in their life-cycle and subject to processing change.” Robotics lends themselves to high output, improved yield and the ability to adapt to process changes in the solar panel fabrication industry, portrays LaSelle.
Many processes within electronics and semiconductor applications demand cleanroom operations. “The trend in robotics for the electronics industry is cleaner robots in a smaller footprint and smaller controllers using less power,” says Joseph Campbell, Vice President of ABB Inc.’s (Auburn Hills, Michigan) Robot Products Group. Campbell’s colleague at ABB, Robot Product Support Group Manager Nicholas Hunt observes, “Cleanroom is a whole environmental process, not just the robot. Robots moving at high speeds shed more particles.” Designing fast-moving robots that maintain their cleanroom certification is a challenge, conveys Hunt.
To maintain cleanroom certification, a robot needs integration within a sterile environment, explains Blanchette. “Cleanroom requirements are very stringent for semiconductor manufacturing. Robots for semiconductor manufacturing need special packaging and delivery into a cleanroom environment so they do not pick up particulate while in transit. The most significant challenge is integrating the robot system within a special cleanroom environment.”
Cleanroom robots are shipped within a protective bag but if that bag is removed on a standard factory floor at the integration site, the robot no longer carries its cleanroom certification. “The robot must go through a cleansing process to become cleanroom certified again,” Blanchette says.
Henry Loos notes that integrators must consider the affect all equipment has on a cleanroom environment, not just the robot. “Operating within a cleanroom does not typically impact the robot. Minimizing the robot’s impact on the cleanroom is a greater challenge.” These challenges are met by employing coatings and lubricants that minimize the potential for contamination caused by robots in clean areas, posits Loos.
LaSelle also says integrators ought to carefully choose equipment going into a semiconductor work cell. “This market segment demands careful consideration of components used to develop a highly robust manufacturing process. The manner in which components are integrated significantly impacts the ultimate cleanliness of the cell. In cleanroom applications, the process of deployment is as important as the hardware itself.”
LaSelle adds, “Robotics affords high throughput, improved yield with the ability to adapt to changes in process equipment.” To maintain yields during assembly tasks and soldering operations, even in low cost labor markets, semiconductor and electronics manufacturers are increasingly turning to robotics, LaSelle says.
Robot manufacturers deliver standard and custom cleanroom robot solutions tailored to the semiconductor or electronics industries’ requirements by investing time and resources prior to the design of systems, applying lessons-learned through experience in cleanroom applications, says LaSelle.
Machines of Choice
Until relatively recently, selective compliance assembly robot arm (SCARA) machines were the robots of choice for fabrication of electronics and semiconductors. “Some electronics and semiconductor manufacturers still use SCARA or cartesian robots, but many see a requirement for articulated and delta robots. Smaller robots, typically, deltas and small serial-link robots, are used for electronic assembly,” says Blanchette.
Similarly, Loos sees the rise of delta robots working along with SCARAs and six-axis articulated robots in the semiconductor and electronics sector. “SCARAs and deltas are at the forefront in the assembly process because of low inertia and high precision at high speeds. With vast improvements in the accuracy and speed of six-axis robots, expect to see them fulfilling both handling and assembly roles.”
ABB’s Campbell and Hunt consider delta robots ideal for semiconductor and electronics applications. “Delta robots have historically been used in picking and packing applications, mostly in the consumer goods and food sectors. Recently, we see more interest in delta robots in assembly applications for electronic components,” relates Campbell. “Circuit board assembly can be done with small Cartesian or SCARAs, although deltas are used for assembly of electrical components and tying solar panels together in photovoltaic applications.”
Hunt says delta robots provide value for electronic and semiconductor assembly due to their inherent accuracy and repeatability. “The accuracy and repeatability of delta style robots are high enough to be of merit in the electronics industry, particularly in solar applications for picking and placing individual photovoltaic cells for panel assembly over a large work envelope.”
LaSelle believes a multitude of robot configurations are suited for the electronics and semiconductor industry. “SCARAs offer a cylindrical work envelope and typically provides higher speeds for picking, placing, and handling processes compared to Cartesian and articulated robots. SCARA deliver greater repeatability and positional capabilities superior to articulated arms,” says LaSelle. SCARAs are used for payloads under 10 kilograms in assembly, packaging, and material handling applications, concludes LaSelle.
End-users want their equipment to perform a myriad of tasks, leading them towards flexible robotics. When feasible, robots in the semiconductor and electronics industry combine assembly, dispensing, machine tending, material handling, material removal and packaging applications. “Robots are used in many processes in electronic and semiconductor manufacturing including assembly and dispensing. Military components require more shock and environmental shielding,” says Blanchette. Military electronics and semiconductors go through more sealing and encapsulation processes than typical consumer electronics so the robot will perform those dispensing applications as part of the assembly process, Blanchette opines.
Combining assembly with dispensing is common, says Henry Loos. “Electronics manufacturing is heavy on assembly but other processes are included as well. Housing sealants, adhesives, and board component vibration protection require dispensing. Machine tending is needed in most high speed machining applications, and assembly operations require a great deal of material handling.”
Robots are also performing inspection tasks, says Blanchette. “Many end-users invest in robots to handle parts in inspection work cells, doing error-proofing during assembly. For a very low cost, end-users can validate their process and increase the yield and quality of their components during manufacturing.”
Continuing, Blanchette says, “Machine tending, material handling and packaging applications are common. Electronics assembly requires robotic handling, snapping electronics into a plastic component, putting all elements together into an assembly, and packing it at the end of the assembly line.”
ABB’s Joe Campbell declares, “High-volume production of most electronic devices screams for robotics. End-users have robots doing kitting, case-packing, and palletizing of consumer electronics. The amount of care going into surface finishes on electronic devices is increasing and we see more trimming, polishing, and, buffing applications using force control to get a consistent finish on electronic components.”
Hunt adds, “We see more thermography, robots looking for hot and cold spots on printed circuit boards. Vision is used to locate electronic components and do testing and inspection through non-tactile sensing. Robot controllers track electronic devices as they move through the production line.”
Tool changers augment the ability of robots to multitask in electronics and semiconductor work cells. “Technology offers high levels of asset utilization through faster production change-over times and redeployment of equipment. Robots deliver high value in their ability to multitask and automate numerous functions within a given workspace. A robot can automatically change its tooling or end-effector to satisfy the task at hand,” says LaSelle.
Using an example to illustrate his point, LaSelle says, “The robot uses one tool to pick substrates and place them into a fixture. Once placed, the robot might use another tool to apply adhesive onto mating surfaces on the part and then places assembled components onto a conveyor. The robot might wield all these tools or use a changing device to handle a gripper for picking and placing, exchanging that device, when called upon, to dispense adhesives.”
As electronic devices become more sophisticated, the need for a more advanced assembly process naturally follows. That increased level of sophistication is a perfect fit for robotics. “The proliferation of sensory input such as vision has created intelligent robotic solutions. In the past, elaborate and expensive fixtures were required to get electronic components and sub-assemblies into a precise location for a robot to pick, manipulate, assemble, then package a part. The same accuracies are achieved using basic in-feeds and vision,” LaSelle postulates.