Patent Application
20170237192
This invention relates an improved force biased spring probe pin for probing ball grid arrays.
Spring probe pins are also often referred to as Pogo™ pins. Pogo™ is a registered trademark of Xcerra Corporation in Norwood, Mass. A spring probe pin or Pogo™ pin is a device used in electronics to establish electrical connection between two circuits. Pogo™ pins are usually arranged in a dense array, connecting together many individual nodes of two circuits or circuit boards. Pogo™ pin connectors are commonly found in automatic test equipment (ATE) in the form of a bed of nails where they facilitate the formation of rapid, reliable, temporary, electrical connections to devices under test. A Pogo™ pin connector may contain just a few Pogo™ pins or may contain many hundreds of Pogo™ pins.
One type of packaged integrated circuit that Pogo™ pins are used to electrically test is a ball grid array (BGA) package 100 such as is shown in
A typical BGA Pogo™ pin connector design used to electrically test solder ball connections on a BGA package 100 is shown in
As shown in
A second typical Pogo™ pin connector design used to electrically test solder ball connections on a BGA package 100 is illustrated in
As shown in
The following presents a simplified summary in order to provide a basic understanding of one or more aspects of the invention. This summary is not an extensive overview of the invention, and is neither intended to identify key or critical elements of the invention, nor to delineate the scope thereof. Rather, the primary purpose of the summary is to present some concepts of the invention in a simplified form as a prelude to a more detailed description that is presented later.
An improved BGA spring probe pin with a spring actuated solder ball receptacle that grips the sides of the solder ball during probing. A method of operating a BGA prober with improved BGA spring probe pins.
Embodiments of the disclosure are described with reference to the attached figures. The figures are not drawn to scale and they are provided merely to illustrate the disclosure. Several aspects of the embodiments are described below with reference to example applications for illustration. It should be understood that numerous specific details, relationships, and methods are set forth to provide an understanding of the disclosure. One skilled in the relevant art, however, will readily recognize that the disclosure can be practiced without one or more of the specific details or with other methods. In other instances, well-known structures or operations are not shown in detail to avoid obscuring the disclosure. The embodiments are not limited by the illustrated ordering of acts or events, as some acts may occur in different orders and/or concurrently with other acts or events. Furthermore, not all illustrated acts or events are required to implement a methodology in accordance with the present disclosure.
An improved BGA Pogo™ pin connector design is illustrated in
As shown in
When not probing a solder ball 420, the ball clamp spring 406 is uncompressed so that the upper portion of the split cylinder, 408A and 408B, protrudes from the open top of the receptacle cylinder 404. When the upper portion of the split cylinder, 408A and 408B, protrudes from the open top of the receptacle cylinder, the pressure exerted by the wire snap ring 412 on the bottoms of the pieces of the split cylinder, 408A and 408 B, causes the upper ends of the split cylinder to spread apart.
During the probing of a solder ball 420 on a BGA package, the spring actuated solder ball receptacle 410 is lowered until the upper ends of the split cylinder, 408A and 408B, come into contact with the solder ball 420. Since the upper ends of the split cylinder, 408A and 408B, are spread apart, they come into contact with the outer circumference of the solder ball 420.
As the improved BGA spring probe is additionally lowered, the ball clamp spring 406 is compressed and the spring actuated solder ball receptacle 410, slides into the receptacle cylinder 404 forcing the upper ends of the split cylinder, 408A and 408B, together and to firmly contact the sides of the solder ball 420. In this manner good electrical contact to the solder balls is achieved even when the solder balls are of a non uniform size or irregular shape.
The improved BGA Pogo™ pin connector design reduces probe failures that result from poor electrical contact to irregular size and shaped solder balls. The improved BGA Pogo™ pin connector design provides increased surface area contact to the solder ball for improved electrical contact. This results in an improved first pass yield and a reduction in the number of parts that a reprobed.
In addition the improved BGA Pogo™ pin connector design reduces probe station down time for BGA Pogo™ pin cleaning, for BGA Pogo™ pin replacement, and BGA probe head realignment.
The split cylinder 412 described has two parts, 408A and 408B, as shown in a top down view in
The split cylinder may have any number of parts. A top down view of a split cylinder with 4 parts is illustrated in
The parts of the split cylinder may have smooth surfaces as shown in
The top down view of a split cylinder design with corrugated sections is illustrated in
The operation of the improved BGA spring probe pin is described in the flow diagram in
In step 700 a probe card with improved BGA spring probe pins is installed on the prober.
In step 710 a BGA package is loaded into the prober with the solder balls facing up.
In step 720 the probe card with the improved BGA spring probe pins is lowered until the inside surfaces of the upper portion of the split cylinders contact the sides of the solder balls.
In step 730 the probe card is additionally lowered causing the ball clamp spring to compress and causing the split cylinders into the cylindrical receptacles. The upper portion of the split cylinders are forced together against the sides of the solder balls as they retract into the cylindrical receptacle ensuring good electrical contact.
In step 740 the prober takes the electrical data on the BGA IC.
In step 750 the probe card is raised so that the ball clamp spring uncompresses causing the upper portions of the split cylinders to emerge from the receptacles and to release the solder balls.
While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only and not limitation. Numerous changes to the disclosed embodiments can be made in accordance with the disclosure herein without departing from the spirit or scope of the disclosure. Thus, the breadth and scope of the present disclosure should not be limited by any of the above described embodiments. Rather, the scope of the disclosure should be defined in accordance with the following claims and their equivalents.
