News
Aguila Technologies (San Marcos, CA) announced that Henkel-Loctite Corp. (Industry, CA) has purchased a license to Aguila's patents on a pre-applied flip chip underfill technology. The Aguila license provides Henkel-Loctite the right to provide wafer-applied flip chip underfill adhesives that will enable fabrication of flip chips at lower cost and increased yield by eliminating the conventional capillary underfill technique.
Aguila's work in the field of advanced flip chip packaging over the past few years has led to over a dozen patents ranging from wafer-level and flip chip processes to no-flow underfills. Aguila's invention provides for a two-portion, or two-level, fluxing adhesive underfill approach. It overcomes the problem of applying an underfill adhesive containing filler particles to a flip chip prior to assembly.
Conventional flip chip technology generally requires that flip chip assemblies be encapsulated with an adhesive, or underfill, to protect the tiny flip chip solder joints from thermal fatigue failure. Particulate fillers in conventional underfills are the essential ingredients that reduce the adhesive's expansion rate with temperature fluctuations. The reduced expansion allows the underfill to match the expansion of the chip's solder bumps, greatly reducing fatigue failures during thermal cycling.
However, the application of underfills to finished flip chip assemblies has historically been a limiting factor to production yield and assembly cost. Conventional underfills are applied through a capillary flow liquid dispensing operation that creates a number of production obstacles.
Ideally, underfills would be applied to flip chips prior assembly. Attempts to put the essential filler particles into no-flow underfills have generally resulted in poor solder wetting and reduced product yields. The filler particles interfere with the flip chip soldering operation. These problems have led to no-flow underfills with no filler particles, limiting their usefulness.
Aguila's two-portion pre-applied underfill eliminates the problem. One portion, constituting the majority of the underfill, is filled with the essential particles that reduce thermal expansion. A second portion comprises few or no filler particles. Yet, it is the second portion that provides the fluxing action during the flip chip soldering operation. This results in a pre-applied underfill that does not interfere adversely with the soldering operation.
Aguila's innovation provides two-portion underfills that are pre-applied to flip chips, either at the wafer level, after wafer sawing, or just prior to the assembly operation. Thus, it eliminates the tedious dispense operation after flip chips are assembled. The underfill may be applied to hundreds of chips at a single time at the wafer, instead of one at a time after assembly.
Copyright 2004, UP Media Group. All rights reserved.
Panasonic Factory Automation (PFA) Co. (Elgin, IL) recently introduced its newest large screen printer, the SP60. It was designed for both the high- and low-volume manufacturer who requires ultra printing accuracy.
The screen printer's benefits include speed--6.0 sec.; accuracy--625 micron (1 mil), with repeatability of 7.5 micron (0.3 mils); and flexibility--full-floating squeegee head, selectable optimized stencil release feature, automated cleaning, universal stencil holding capability to handle 21 in. to 29 in. frames without the need for adapters.
The printer also features an intuitive programming interface. Its accurate cartridge head minimizes errors, resulting in greater productivity and efficiency.
According to IPC (Northbrook, IL), the North American IMS/PCB Industry book-to-bill ratio for January remained positive at 1.08.
The ratio is calculated by averaging the index numbers for orders booked over the past three months and dividing by the average index numbers for sales billed during the same period. A ratio of more than 1.00 suggests that current demand is ahead of supply, which indicates probable near-term growth.
Shipments increased 28.4% from January 2003 and orders booked increased 19.8% year-on-year. The shipment index was 118.1, down 6.5% from December 2003 and the IMS/PCB booking index was 125.2, down 8.7% sequentially.
The index shows how current PCB shipments and bookings relate to an index point. In this case, 1992 was chosen as the index point because it was a stable growth year for U.S. PCB manufacturers. A shipment index number of 117.0, for example, indicates that shipments are 17% higher than average shipments for the same time period in 1992.
Percentages based on the index numbers reflect changes in the size of the industry. Data reported by current participants in IPC's monthly survey, however, tell a different story. These participating companies report that their shipments increased 25.1 percent in January 2004 over January 2003, and that their orders booked increased 18.2 percent in January, year over year.
Together, these figures show a North American PCB industry that has contracted, but the companies that remain in the industry are doing better than last year.
The information in IPC's monthly industry statistics is based on data provided by PCB manufacturers that participate in IPC's monthly IMS Statistical Program. The companies reportedly represent 60% of the U.S. IMS industry.
Copyright 2004, UP Media Group. All rights reserved.
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