Die attach goes mainstream: for IC deposition, printer platforms are supplanting dispensers on die bonders.I have previously talked about the inherent advantages of mass imaging techniques when applied to semiconductor packaging. The same efficiencies--speed, accuracy, limitless deposit volumes--that have been realized in the surface-mount market have also taken hold in packaging. Some of the countless examples of printing applications within semiconductor processing include wafer bumping, solder ball In BGA chip packages, it is the tiny globe of solder that provides the contact between the chip package and the printed circuit board. Also called a "solder bump." See BGA. placement and encapsulation (1) In object technology, the creation of self-contained modules that contain both the data and the processing. See object-oriented programming.
(2) The transmission of one network protocol within another. . Advancements in wafer handling and advanced materials Advanced Materials is a leading peer-reviewed materials science journal published every two weeks. Advanced Materials includes Communications, Reviews, and Feature Articles from the cutting edge of materials science, including topics in chemistry, physics, deposition techniques have taken the crossover Crossover
The point on a stock chart when a security and an indicator intersect. Crossovers are used by technical analysts to aid in forecasting the future movements in the price of a stock. In most technical analysis models, a crossover is a signal to either buy or sell. technology advantages of the printing platform and enabled it for ultra-thin die attach materials applications, moving the process closer to mainstream manufacturing.
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Traditionally, die attach adhesive pastes have been applied with a conventional dispensing system as part of the die bonding machine. But this presents challenges as semiconductor manufacturers move to higher volume requirements and strive to reduce device footprints. Just as in the SMT (1) (Surface Mount Technology) See surface mount.
(2) (Station ManagemenT) An FDDI network management protocol that provides direct management. Only one node requires the software.
SMT - Station Management market, placement speed has increased dramatically in packaging. With dispensers, the only way to approach the volumes now being produced with modern placement systems is to add more dispensers, which is prohibitive in terms of cost and floor space.
Dispensing also has drawbacks for the chip footprint because the process requires the formation of an adhesive fillet fillet /fil·let/ (fil´et)
1. a loop, as of cord or tape, for making traction on the fetus.
2. in the nervous system, a long band of nerve fibers.
1. around the chip, which increases the overall area of the chip. Also contributing to a larger footprint is the tendency of paste adhesives for resin bleed Printing at the very edge of the paper. Many laser printers, including all LaserJets up to the 11x17" 4V, cannot print to the very edge, leaving a border of approximately 1/4". In commercial printing, bleeding is generally more expensive, because wider paper is often used, which is later . To accommodate for this, space has to be left around the surrounding bond pads to ensure that they are not affected by excessive bleed. Not only are there speed and size constraints with conventional die attach methods, but there are also quality and reliability concerns. Accurately placing a chip into a tiny dot of adhesive is a highly delicate operation. If there is any tilt to the chip, or if the chip is applied with too much or too little force, there are problems with even distribution of the die attach material. If the adhesive coverage is insufficient or uneven, reliability of the final package is in question.
A mass imaging/printing platform for die attach material deposition can resolve many dispensing-related issues. Using a printing platform, new developments in wafer handling and materials application techniques have resulted in the ability to coat wafers with ultra-thin die attach materials down to 25 [micro]m thickness with speed, accuracy and uniformity. One of the most delicate aspects of wafer printing is providing the stability to coat an extremely thin--50 [micro]m--yet, relatively large in diameter--300 mm--wafer. To ensure uniform material deposition, the wafer must be stable, secure and perfectly flat during the imaging process. An ultra-flat pallet is the key enabler here (Figures 1, 2 and 3). The securing mechanisms of some pallets tend to pull the wafer so that either a) the wafer can break from the force or b) the wafer is not perfectly flat, which leads to uneven distribution of the material being applied. Also key: the precision of the printer and the tool used to apply the adhesive paste. We suggest a specially engineered squeegee in combination with a die attach stencil stencil, cutout device of oiled or shellacked tough and resistant paper, thin metal, or other material used in applying paint, dye, or ink to reproduce its design or lettering upon a surface. or screen.
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The advantages of this process are the elimination of the fillet and subsequent reduction of paste adhesive volume-potentially by a factor of 10 on die less than 0.5 x 0.5 mm, the ability to print material in complex shapes without any adverse effect on line speed and simplifying the supply chain by requiring only one paste formulation for various process needs. Mass imaging of adhesive paste for die attach also has cost savings over dry film. Film can cost as much as 30% more than adhesive paste and has to be manufactured in multiple thicknesses and widths for different applications so is not as versatile as paste.
Then there is the ability to process even thinner wafers. We have observed the coating of 150 mm wafers only 50 [micro]m thick. In our estimation, backside BACKSIDE, estates. In England this term was formerly used in conveyances and even in pleadings, and is still, adhered to with reference to ancient descriptions in deeds, in continuing the transfer of the same. property. wafer coatings for die attach and other applications such as epoxy epoxy
Any of a class of thermosetting polymers, polyethers built up from monomers with an ether group that takes the form of a three-membered epoxide ring. The familiar two-part epoxy adhesives consist of a resin with epoxide rings at the ends of its molecules and a curing and wafer-level protective coatings will emerge as the standard for semiconductor processing.
Clive Ashmore is global applied process engineering manager at DEK DEK - Data Encryption Key (dek.com); email@example.com. His column appears semimonthly sem·i·month·ly
Occurring or issued twice a month.
n. pl. sem·i·month·lies
A semimonthly publication.
At intervals twice monthly. See Usage Note at bi-1.
Noun 1. .