Cleanroom Robotics Grasps FPD Industry
By Susan English
Genmark`s Gencobot III, Brooks` MagnaTran 60, and Equipe Technologies` FPD-300 series robots all have one thing in common–they are specifically designed to operate in Class 1 cleanroom environments. The latest in magnetically driven, wafer-handling vacuum chamber robots, the systems are specifically targeted at the new and rapidly expanding flat-panel display (FPD) industry. FPD manufacturers are currently scrambling to put together a common standards platform to keep pace with advances in what promises to be a hotly-contested world-wide industry.
U.S. flat-panel displays are active-matrix liquid crystal displays used in color laptop and notebook computers, camcorder viewfinders, and flat TVs. As electronic devices such as personal computers become smaller and more portable, flat-panel displays are replacing CRTs because of their reduced size, weight, and power consumption advantages.
“The emerging FPD industry is today where the semiconductor industry was in its early days–badly in need of manufacturing standards that benefit both the display manu- facturers and their equipment and materials suppliers,” says William Reed, president of Semiconductor Equipment and Materials Inter- nat ion al (SEMI). SEMI, which already has its own North American Flat Panel Display Division, has tackled FPD standards, because most of the technology used in the devices is an outgrowth of IC chip production. Using the IC industry as a guide, Reed quotes figures from Data quest projecting a $4 billion market for displays in 1995.
Until recently, Japan has dominated the FPD market. Indeed, in 1990, 98 percent of the market belonged exclusively to Japanese manufacturers, according to Bernard R. Casey, Director of Sales and Marketing at Genmark Automation (Sunnyvale, CA). With $8 million in sales, a current backlog of $5.4 million, and estimated 1995 sales of $14 million, based on run-rate, Genmark is the high-end giant, carrying a line of over 1,000 robots selling to OEMs for integration into their semiconductor capital equipment. And, like Brooks Automation and Equipe Technologies, Genmark plans to be a supplier to the U.S.-based international elite, as well as a big player in the European, Japanese, and Pacific Rim OEM and FPD end-user markets. The company estimates that the entire global flat-panel display market will reach $19 billion by the turn of the century.
Sometimes, though, it`s easier to gauge the growth of an exploding market by looking at the income statements of smaller OEM suppliers, like Equipe Technologies, Inc., (Sunnyvale, CA). At the other end of the wafer-handling robot market, the company was started only 4-1/2 years ago by former Genmark employees, including its president, James Cameron. Although small, they have a reputation for clean and reliable robots and claim to have sold more robots than any other company in 1994, posting 1993 sales of $2.4 million and 1994 sales of over $11.4 million, catapulting gross annual revenues to 464 percent. Equipe`s president says that one out of three of its robots goes to the Pacific Basin area and is definitely planning to target Japan as a future market. The company is currently setting up an office in Lindau, Germany to support its European OEMs.
There are many similarities and some cross-over of technology between the semiconductor industry and the emerging flat panel display industry. In the past few years, companies such as XMR (Santa Clara, CA) and Plasma-Therm (St. Petersburg, FL) have extended their semiconductor wafer processing capabilities and their use of robots into designing, manufacturing, and marketing capital equipment for the processing of FPDs. A new player in the FPD market with a leg-up in semiconductor/flat-panel display transfer technology is PRI Automation, Inc. (Billerica, MA), a leading manufacturer of factory automation systems used by semiconductor manufacturers to automate the fabrication of integrated circuits in their front-end cleanroom manufacturing operations. Formerly known as “Precision Robots,” the company went public in October 1994 and now considers itself in the materials handling business and not the “robot business,” according to PRI president Mitchell Tyson, who says that all products are designed to work in sub-Class 1 cleanroom areas.
Founded in 1982, the company set up its own separate automation systems division less than a year ago, which identified FPDs as one of its primary areas of focus, positioned itself to adapt its products for FPD handling, and is currently targeting OEMs, end users, and consortiums. Designed for clustering in an atmospheric vs. a vacuum environment, the company`s unique “RoboTrak” and “AeroTrak” Systems utilize an automated, articulated-arm robot that can move in and out of process tool bays mounted either on a linear track embedded in the cleanroom floor or running along a patented “Overhead Monorail” system extending all across a fab.
It also sells a Machine Loading Robotic Vehicle (MLRV), which is a wireless track system incorporating an enclosure that provides a contamination-free, Class 1 mini-environment. Its successor, the 360MLR, is designed for FPD applications, as well as other payloads. Unlike other companies, whose sole product is robots, PRI designs and markets whole systems applications, which carry higher price tags: interbay automation systems sell for between $5-$10 million dollars. Prices for the company`s intrabay and cell automation systems range from approximately $150,000 to $1,000,000. Tyson projects a 50-60 percent growth rate over last year`s sales figures of $36 million. (Wall Street analysts are predicting $55 million in sales for PRI`s `94-`95 fiscal year.)
As semiconductor manufacturing becomes more complex, control of contamination during wafer handling becomes an increasingly important in maximizing manufacturing yields. Like semiconductor wafers, FPDs, are increasingly being handled in controlled, ultraclean Class 1 mini-environments within the regular Class 100 cleanroom area. FPDs are also manufactured with deposition and etch processes, but FPDs are much larger than semiconductor wafers. A cassette containing 25 pieces of glass panel typically measuring 600mm 𨝄 mm each may weigh up to 75 lbs., requiring a very sturdy robotic “arm” to maintain positional accuracy. A silicon wafer, on the other hand, typically measures only 300 mm ¥ 300 mm in size.
Just as the shrinking line width on the semiconductor chip has made the use of vacuum robotics essential in clean manufacturing from the standpoint of increased yield and throughput, expanding substrate sizes in FPD technology are making contamination control a critical issue in this new technology. Although because of their larger feature sizes, they can tolerate contamination by particles larger in size than semiconductors, the relatively small number of flat panel displays per substrate means that a single defect has a much greater impact on FPD yields. With just two to six panels per substrate at a cost of about $500-$600 per 10-in. display, as opposed to hundreds of die per wafer, yield loss due to particulates at this rate is unacceptable.
Vacuum robotics is a technology in itself. Increasing throughput is made more difficult in a vacuum environment. Unlike atmospheric transfer robots, which use vacuum suction to hold a wafer in place when being carried, vacuum transfer robots use gravity control and the friction between the wafer and the robot “end effector” (the robot hand). Carrying a wafer in a vacuum requires sophisticated motion control of acceleration, deceleration, trajectory, and vibration to maximize the speed of wafer transfer, while maintaining wafer position, placement, and repeatability.
Brooks Automation pioneered the “frog-leg” robot in 1984, which has only rotary bearings as moving parts, representing the optimal solution for minimizing contamination. The company believes that the elimination of moveable vacuum seals in its new generation MagnaTran robots will further enhance its particle performance. Other companies, too, have made design changes to reduce both wafer contamination and electrostatic discharge in limiting the number of moving parts within the vacuum environment and above the wafer plane, and in the use of non-offgassing materials.
Referencing the growing importance of information display technology to the global personal computer, telecommunications, and consumer electronics industries, SEMI, together with the Society for Information Display (SID) and the United States Display Consortium (USDC), have announced plans to join forces on a three-day technical symposium, product exhibit, and business conference called Display Works `96 at the San Jose Convention Center on February 6-8, 1996. The event is designed to explore both the technical and business challenges of this emerging market. n