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Is the Lack of Fine-Pitch Probes and Fixtures Preventing Product Advancement? Recent advances in micro-probe technology may have broken through the roadblock to miniaturization. Durable, fine-pitch probes in sizes from 20 to 8 mils along with corresponding test fixtures support product miniaturization in cases where the electronic assemblies have small testing targets on close center-to-center spacing that could not be contacted by traditional test probes. When this occurs, electronics manufacturers must locate and utilize fine-pitch test probes or risk the following:

(1) not being able to advance product functionalities, due to inability to miniaturize
(2) omission of at least some test procedures
(3) scrapping a product update and possibly becoming less competitive

Fortunately, a new generation of fine-pitch test-probes can now probe these electrical targets with ±15 micron pointing accuracy on 10 mil center-to-center placement. One supplier, AlphaTest Corp. (Shelton, WA), has a complete range of such fine-pitch test probes under the µHELIX® Test Probe brand name in diameters of 20, 16, 12 and 8 mils.

These include fine-pitch spring-loaded test probes that can meet the mechanical challenges of testing miniature circuits such as hybrids, RFID antennas, flex-circuits, flat panels and many of the following package types: StripLine, BGA, CSP, SoC, SiP, MEMS, mcm and photonic devices.

As an example in the field of advanced medical electronics, St. Jude Medical Inc. (Scottsdale, AZ) incorporates fine-probe testing of miniature implant products that it designs and manufactures for critical heart-related devices such as electronic pacemakers and defibrillation leads. All of these products must comply with high performance standards as well as low physiological implant complications, and long-term durability.

“In order to test these medical devices, we use the fine-pitch probes installed in electromechanical test fixtures,” says David Montgomery, St. Jude Medical Production Engineering Manager. “The fixtures include a specified number of fine-pitch test probes (normally 20 mil or smaller), a guide plate and a latching mechanism, all manufactured by AlphaTest.”

Montgomery explains that the “package” for the electronics must be small and highly ergonomic in order to remain in the human body. And for that reason it is difficult to utilize an off-the-shelf test probe fixture.

He adds that for over 10 years AlphaTest has been a very capable collaborator in the design and engineering of fine-pitch probe test fixtures, and supply products that are consistently accurate and reliable. AlphaTest Corp. offers over 700 models of fine-pitch probes with short lead times. The company also offers custom fine-pitch test probes, as well as design and fabrication of test fixtures.