PROBE ARRAY AND METHOD OF ITS MANUFACTURE
A method of forming a probe array includes forming a layer of tip material over a block of probe material. A first electron discharge machine (EDM) electrode is positioned over the layer of tip material, the EDM electrode having a plurality of openings corresponding to a plurality of probes to be formed. Excess material from the layer of tip material and the block of probe material is removed to form the plurality of probes. A substrate having a plurality of through holes corresponding to the plurality of probes is positioned so that the probes penetrate the plurality of through holes. The substrate is bonded to the plurality of probes. Excess probe material is removed so as to planarize the substrate.
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1. Field of the Invention
The present invention is related to a method of making an array of probes for use in probing electronic devices, such as a probe card for probing the dies on a semiconductor wafer.
2. Related Art
Semiconductor dies must be tested during the manufacturing process to insure the reliability and performance characteristics of integrated circuits on the dies. Accordingly, different testing procedures have been developed by semiconductor manufacturers for testing semiconductor dies. Standard tests for gross functionality are typically performed by probe testing the dies at the wafer level. Probe testing at the wafer level can also be used to rate the speed grades of the dies.
Testing a large number of integrated circuit chips in parallel at the wafer level provides significant advantage since test time and cost are substantially reduced. At present, large scale testers including mainframe computers are needed to test even one chip at a time, and the complexity of these machines is increased when the capability of testing arrays of chips in parallel is added. Nevertheless, because of the time savings parallel testing provides, high pin-count testers capable of probing and collecting data from many chips simultaneously have been introduced, and the number of chips that can be tested simultaneously has been gradually increasing.
Substantial lower cost would result from an improved wafer test and burn-in scheme that permits parallel test and burn-in of the chips on a wafer before dicing.
As wafer testing requirements become more sophisticated, the need for high density probes, and efficient and relatively inexpensive methods of manufacturing them continues to be a challenge. Accordingly, a need exists for an inexpensive and efficient method of manufacturing high density probe array.
SUMMARY OF THE INVENTIONThe present invention is directed to a probe array for testing of semiconductor wafers and a method of its manufacture that substantially obviates one or more of the problems and disadvantages of the related art.
There is provided a method of manufacturing a probe array including forming a first substrate having a plurality of through holes. A second substrate is formed having a plurality of probe tips embedded therein. A plurality of wires are bonded to corresponding probe tips of the second substrate. The through holes of the first substrate are mated with the plurality of wires. The second substrate is removed. The first substrate is planarized, and connections are formed on the first substrate to the plurality of wires for connecting to external signal sources.
In another aspect there is provided a method of forming a probe array including forming a layer of tip material over a block of probe material. A first electron discharge machine (EDM) electrode is positioned over the layer of tip material, the EDM electrode having a plurality of openings corresponding to a plurality of probes to be formed. Excess material from the layer of tip material and the block of probe material is removed to form the plurality of probes. A substrate having a plurality of through holes corresponding to the plurality of probes is positioned so that the probes penetrate the plurality of through holes. The substrate is bonded to the plurality of probes. Excess probe material is removed so as to planarize the substrate. Advantages of the method of making the probe array according to the present invention include the use of two stages of steps with two different substrates. Therefore, the processing steps of the two stages can be carried out in parallel and independent of one another. Any errors or defects that may be present require only a repetition of one set of steps. Also, the resultant probe array has through holes that provide support along at least a segment of the probe. The support is especially advantageous in a probe array with lateral contact movement or wiping.
In another aspect there is provide a probe array including a substrate, and a plurality of probes for contacting test terminals on a test device. Each probe has a stem and a tip. Each probe penetrates the substrate for support. The substrate has a plurality of through holes such that the stems of the probes penetrate the through holes and are bonded to the substrate.
Additional features and advantages of the invention will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the invention. The advantages of the invention will be realized and attained by the structure and particularly pointed out in the written description and claims hereof as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to illustrate exemplary embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:
Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
As shown in
An electron discharge machine (“EDM”) is then used to shape the tip material 101 and probe material 102 into basic probe shapes (steps 902-903). A first EDM electrode 201 shaped in the form of the desired probe array is applied to the block of tip material 101 and probe material 102 as shown in
As shown in
The EDM electrodes 201 may be formed of any conductive material that can be etched, machined, or otherwise processed to form the desired patterns. For example, the first EDM electrode 201 may be formed of graphite, which can be patterned using laser ablation (e.g., using an excimer laser). As another example, the second EDM electrode 701 may be formed of silicon, which may be highly doped and which can be patterned by etching pits into the surface of the silicon. Optionally, a surface of the EDM electrode may be metallized by sputtering, plating, chemical vapor deposition, and other techniques, or otherwise treated.
Thus, there is provided a method of forming a probe array including forming a layer of tip material 101 over a block of probe material 102. A first electron discharge machine (EDM) electrode 201 is positioned over the layer of tip material 101, the EDM electrode 201 having a plurality of openings corresponding to a plurality of probes 401 to be formed. Excess material from the layer of tip material 101 and the block of probe material 102 is removed to form the plurality of probes 401. A substrate 501 having a plurality of through holes 502 corresponding to the plurality of probes 401 is positioned so that the probes 401 penetrate the plurality of through holes 502. The substrate 501 is bonded to the plurality of probes 401. Excess probe material is removed so as to planarize the substrate 501. The tip material may be further treated before or after forming the probes. For example, the tip material may be treated using ion implantation techniques, plating, etc.
As shown in
As mentioned above, the sacrificial material 1208 is not necessary. The probe material 1206 could be provided by itself, and the electrode 1002 could simply etch through probe material 1206. Moreover, if used, the sacrificial material 1208 need not be shaped by the electrode 1002. That is, the electrode 1002 may be stopped in
Regardless of whether or not the sacrificial material 1208 is etched, how the sacrificial material 1208 is adhered to and then released from the probe material 1206 is not critical to the invention. Likewise, the material used as the sacrificial material 1208 is not critical to the invention. For example, the probe material 1206 and the sacrificial material 1208 may be adhered together using any suitable adhesive (e.g., epoxy, etc.). The probe material 1206 and the sacrificial material 1208 may then be separated by dissolving, etching away, or otherwise removing the adhesive. As another example, the sacrificial material 1208 may be dissolved or etched away to separate the probes 1510 from the sacrificial material.
As an alternative, the initial block of probe material 1206 may be a composite material that includes one material for the bodies of probes 1510 and a different material for the tips of probes 1510. For example, the initial block of material from which the result shown in
An exemplary use of the loose probes 1510 shown in
Like the EDM electrode 201, the EDM electrode 1002 may be formed of any conductive material. Also, the cavities 1004 may be patterned in the electrode 1002 using any suitable method. For example, the cavities 1004 may be etched, machined, etc. into the electrode 1002. As another example, the cavities 1004 may be formed using laser ablation. As yet another example, the sacrificial substrate 1208 (e.g., a silicon wafer) may be covered with a photo resist, and the photo resist patterned, developed, and removed, such that photo resist remains on the sacrificial substrate 1208 only where cavities 1004 are to be formed. The sacrificial substrate 1208 is then metalized (e.g., by plating, deposition, etc.), forming a bottom plate of the electrode around the patterned photo resist, which is then removed, leaving cavities 1004 in the newly formed bottom plate.
Advantages of the method of making the probe array according to the present invention include independent processing of two different substrates. Therefore, the processing steps of the two stages can be carried out in parallel and independent of one another. Any errors or defects that may be present require only a repetition of one set of steps. Also, the resultant probe array has through holes that provide support along at least a segment of the probe. The support is especially advantageous in a probe array with lateral contact movement or wiping (i.e., movement of the probes first laterally along the surface of the device under test, and then “bumping” over a terminal pad on the device under test).
It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
Claims
1. A method of manufacturing a plurality of probes, said method comprising:
- providing a block of material;
- removing with an electron discharge machine (EDM) material from said block of material to form said plurality of probes.
2-21. (canceled)
Type: Application
Filed: Feb 10, 2009
Publication Date: Jun 4, 2009
Applicant:
Inventors: Gaetan L. Mathieu (Varennes), Benjamin N. Eldridge (Danville, CA), Gary W. Grube (Pleasanton, CA)
Application Number: 12/368,531