1. Field of the Invention
This invention relates to a probe head for testing the electrical properties of a semiconducting device under test. More particularly, the probe head contacts both sides of the semiconducting device under test and can receive electrical and optical inputs. The probe head is particularly effective for testing the characteristics of a light emitting diode (LED).
2. Description of the Related Art
An LED is a semiconductor device that emits incoherent monochromatic light when electrically biased in a forward direction. The effect is a form of electroluminescence with the color and wavelength dependent on the semiconducting material used. For example, aluminum gallium arsenide generates red and infrared light, gallium nitride generates green light, and zinc selenide generates blue light.
With reference to
Interference from adjoining LEDs may influence the electrical and optical data acquired during wafer stage test. More accurate measurement of LED characteristics may be obtained if testing is performed following singulation.
One aspect of the present invention is a probe head component for testing the properties of a semiconducting device under test, which includes a dielectric film supporting at least one semiconducting device under test, a support frame tautly supporting the dielectric film, a first probe for contacting a first side of the semiconducting device under test, and a second probe moveable between a first position and a second position wherein the second position is for contacting an opposing second side of the semiconductor device under test.
Another aspect of the present invention is a probe head for testing the properties of a semiconducting device under test, which includes a dielectric film supporting at least one semiconducting device under test, a support frame tautly supporting the dielectric film, a first support positioning a first probe for electrically contacting a first side of the semiconducting device under test, and a second support having a actuator to move a second probe between a first position and a second position wherein the second position is for electrically contacting an opposing second side of the semiconductor device under test.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the invention will be apparent from the description and drawings, and from the claims.
For the purpose of illustrating the invention, the drawings show a form of the invention that is presently preferred. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:
Referring now to the drawings in which like reference numerals indicate like parts, and in particular, to
Dielectric film 24 is scanned using a camera 32, for example, a line scanning camera, with software that will capture the position of the devices enabling a wafer map to be built. Alternatively, camera 32 is offset by a known distance from first probe 28. The device under test is passed through camera 32's field of view before being tested. Using software, the exact position of the device under test within camera 32's field of view is determined. This data is then used to drive a probe controller the exact amount of distance along the X and Y-axes to bring the device under probes 28 and 30. This scanning camera can be part of the probing equipment or can be equipment specifically for scanning the film frames. The data obtained by the camera can be transferred to other probing equipment by means of network protocol, typically internet protocol (IP).
When the device is at the proper position, first probe 28 electrically contacts first electrically conductive pad 12. Second probe 30 is moveable between a first position P1, that is remote from device 10, and a second position P2 that makes electrical contact with second electrically conductive contact pad 14. As second probe 30 moves from first position P1 to second position P2, as indicated by the arrow in
Second probe 30 is typically formed from an electrically conductive material, such as a copper alloy and may be of the type known in the industry as a pogo contact. Second probe 30 is in the form of a rod having a diameter of about 0.2 millimeter. Second probe 30 terminates at a probe tip 33 that is effective to pierce dielectric film 24 and to electrically contact device 10 under test. For example, probe tip 33 may have a reduced diameter point.
With reference to
When device 10 under test is an LED, in addition to electrical properties, it is desirable to evaluate the optic properties of the device. Now referring to
The glass plate is typically coated with an electrically conductive layer that is also transparent to the light emitted by the LED, such as indium tin oxide.
A first cable 46 transmits optical and electrical information to a piece of test equipment, such as a computer and a second cable 48 transmits electrical information to the test equipment.
One or more embodiments of the present invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. For example, devices other than LEDs may be tested using the probe head of the invention. Accordingly, other embodiments are within the scope of the following claims.
This patent application claims benefit under 35 U.S.C. § 119 (e) of copending, U.S. Provisional Patent Application Ser. No. 60/558,647, filed Apr. 1, 2004, the disclosure of which is incorporated by reference herein in its entirety.
Number | Name | Date | Kind |
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5412314 | Fukunaga et al. | May 1995 | A |
5467020 | Boyette et al. | Nov 1995 | A |
6384612 | Freund et al. | May 2002 | B1 |
6404181 | Hikita | Jun 2002 | B1 |
Number | Date | Country | |
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20050225339 A1 | Oct 2005 | US |
Number | Date | Country | |
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60558647 | Apr 2004 | US |