Television – Special applications – Manufacturing
Reexamination Certificate
1999-05-21
2001-03-27
Kelley, Chris (Department: 2613)
Television
Special applications
Manufacturing
C382S151000
Reexamination Certificate
active
06208375
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of probe positioning methods and systems, and particularly to methods and systems used to locate test probes on micro-sized devices.
2. Description of the Related Art
The testing of “micro-sized” devices, i.e., integrated circuits (ICs) and micro-electromechanical (MEM) devices, prior to their assembly into closed packages, requires the use of one or more very small test probes. For an IC, the test probes are used to sense or apply electronic parameters, while a MEM device may require the testing of parameters that are, for example, mechanical, fluidic, pneumatic, or acoustic in nature.
Many test probe systems have been developed, primarily for use with ICs. One such system, typical of those in the field, is described in U.S. Pat. No. 5,539,676 to Yamaguchi, which is directed to a system for probing semiconductor wafers. A probe card holds a fixed array of probes, and the wafer is mounted on a movable table. The positions of the probes are known relative to a point on the card, and this information is stored in a memory device. A camera is moved so that a reference probe is aligned with a reference point in the view field of the camera. A processor uses the camera position information to determine the absolute coordinates of the reference probe, from which the positions of each of the other probes can be calculated. All of the test probes on the probe card are simultaneously brought into contact with the wafer to be tested. There is no means by which an individual feature on the wafer can be targeted for probing, nor of uniquely identifying an individual probe from among the probe card's array of probes.
Another Yamaguchi patent (U.S. Pat. No. 5,530,374) discloses a similar system, except that the camera is aligned with a reference marker on the probe card rather than a reference probe, with the positions of the probes known with respect to the marker. However, the limitations found in the previous system are present here as well.
The Yamaguchi systems work well when a number of identical wafers are to be tested in succession, and the array of points to be probed does not vary from wafer to wafer. However, these systems are not well-suited for use with small numbers of highly unique devices, such as MEM devices. Here, different probe types may be needed to accommodate the different parameter types that might be found on a MEM device. Furthermore, due to the interdisciplinary nature of a MEM device, which may combine mechanical, electric, and fluidic aspects, for example, it is likely to have a much more irregular surface than that of an typical IC wafer. Conventional high volume probe card-based test probe systems are unable to provide the kind of flexibility called for in this type of application.
SUMMARY OF THE INVENTION
A test probe positioning method and system are presented which overcome the limitations noted above, by providing the ability to identify and precisely locate individual probes from among a plurality of probes, and of independently moving a selected probe to a selected target feature.
The novel method is practiced by displaying an image of a micro-device to be probed on a display screen. A “target feature”, i.e., a specific location on the device which is to be probed, is selected—either by manual means such as a computer mouse, or by automatic means, in which, for example, search and recognition software select a target feature based on previously-stored information. The pixel address of the selected target feature within the displayed image is determined. A test probe is introduced into the field of view of the image, and a means is provided whereby the pixel address of the test probe within the displayed image is determined. With the target and probe addresses known, the probe is moved to bring it into contact with the target feature.
An individual probe is identified from among a plurality of probes by means of coded markings applied to each. In a preferred embodiment, the pattern of markings on each probe is unique. The markings are a known distance apart and from the probe tip. When placed within the field of view, the identity of each probe can be determined by observing its coded pattern of markings. Furthermore, by knowing the actual spacing between markings and probe tip, combined with knowledge of the camera position and the angle of the probes with respect to the camera, the position of the probe tip can be determined relative to the camera in three dimensions. In this way, an individual probe can be identified, precisely located, and then moved as necessary to contact the selected target feature. This capability, in combination with a routing network interposed between the probes and the external test equipment used to apply stimuli to and receive data from the various probes, enables any one of a system's probes to be connected to an appropriate piece of test equipment.
Further features and advantages of the invention will be apparent to those skilled in the art from the following detailed description, taken together with the accompanying drawings.
REFERENCES:
patent: 5530374 (1996-06-01), Yamaguchi
patent: 5539676 (1996-07-01), Yamaguchi
patent: 5585738 (1996-12-01), Kuji et al.
patent: 5631565 (1997-05-01), Winter
patent: 5696837 (1997-12-01), Green
patent: 5869975 (1999-02-01), Strid et al.
patent: 5916715 (1999-06-01), Fulford, Jr. et al.
patent: 6089107 (2000-07-01), Canella et al.
patent: 6118894 (2000-09-01), Schwartz et al.
Kay Robert L.
Lane Steven T.
Elite Engineering Corporation
Kelley Chris
Koppel & Jacobs
Vo Tung
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