1. Field of the Invention
The present invention relates generally to a probe used in a probe card for probing a device under test (hereinafter referred to as “DUT”), and more particularly to a microelectromechanical probe, a method of manufacturing the microelectromechanical probe, and a probe set using the microelectromechanical probe.
2. Description of the Related Art
Compared with the traditional machining process, the aforesaid MEMS manufacturing process is faster, more favorable for batch and mass production and more precise in manufacturing the probe 10. However, the MEMS manufacturing process causes a restriction on the shape of the probe 10. That is, the pinpoint portion 13 of the probe 10 can taper off by only left and right sides 131, 132 thereof inclining to approach each other, but front and rear sides 133, 134 of the pinpoint portion 13 are hard to be made inclining to approach each other. Therefore, the pinpoint portion 13 has an elongated probing end 135 with a certain surface area for contacting the DUT. The probing end 135 is simply depicted as a straight line in
The present invention has been accomplished in view of the above-noted circumstances. It is an objective of the present invention to provide a microelectromechanical probe, the probing end of the pinpoint portion of which has relatively smaller area, thereby making relatively smaller probe marks upon probing the DUT, easily piercing the passivation layer of the DUT, and more recognizable in the automatic pinpoint recognition process.
To attain the above objective, the present invention provides a microelectromechanical probe which has a top surface, a body portion, and a pinpoint portion substantially extended in a probing direction from the body portion and provided with a first side, a second side opposite to the first side and a probing end substantially oriented in the probing direction. The microelectromechanical probe is adapted to move relative to a DUT in the probing direction to contact the DUT by the probing end. The pinpoint portion has a cutting face provided on the top surface, adjoining the first side, the second side and the probing end, and having at least one cut mark formed by a cutting process. The at least one cut mark is substantially extended from the first side to the second side and non-parallel to the probing direction, and comprises an edge cut mark located at an edge of the cutting face. The cutting face descends from the edge cut mark to the probing end.
In other words, the microelectromechanical probe of the present invention is initially formed by a MEMS manufacturing process, and then a cutting process is performed to remove a part of the initially formed pinpoint portion so as to simultaneously form the cutting face and cut off a part of the initially formed probing end. As a result, the probing end of the microelectromechanical probe of the present invention has relatively smaller area, thereby making relatively smaller probe marks upon probing the DUT, easily piercing the passivation layer of the DUT, and more recognizable in the automatic pinpoint recognition process. Besides, the at least one cut mark is formed in a way that the cutting process is performed to cut the pinpoint portion from the first side to the second side in a cutting direction non-parallel to the probing direction. In this way, a plurality of probes can be cut in a same cutting process, so that the microelectromechanical probe of the present invention is favorable for batch and mass production.
It is another objective of the present invention to provide a method of manufacturing the aforesaid microelectromechanical probe.
To attain the above objective, the present invention provides a method of manufacturing a microelectromechanical probe, which includes the steps of:
a) forming a probe body on a substrate by a microelectromechanical system manufacturing process in a way that the probe body has a bottom surface facing the substrate, a top surface opposite to the bottom surface, a body portion, and a pinpoint portion which is substantially extended in a probing direction from the body portion and provided with a first side, a second side opposite to the first side and a probing end substantially oriented in the probing direction; and
b) cutting the pinpoint portion of the probe body from the first side to the second side in a cutting direction non-parallel to the probing direction by a cutting tool, so as to simultaneously provide the pinpoint portion a cutting face on the top surface and reduce an area of the probing end in a way that the cutting face is provided at an edge thereof with an edge cut mark and the cutting face descends from the edge cut mark to the probing end.
Preferably, in the MEMS manufacturing process in the step a) of the aforesaid method, a plurality of probe bodies are formed on the substrate in a way that the probe bodies are substantially arranged at a same posture and the probing ends of the probe bodies are aligned in the cutting direction; in the step b), the probe bodies, which are aligned in an imaginary straight line in the cutting direction, are cut by the cutting tool in a same cutting process. In this way, a plurality of probes can be cut in the same cutting process, so that the method is favorable for batch and mass production of the microelectromechanical probe.
Preferably, in the step a) of the aforesaid method, a sacrificial layer is formed on the substrate in the MEMS manufacturing process, and the probe body is fixed on the substrate by the sacrificial layer. The sacrificial layer is removed after the step b), so that the probe body is separated from the substrate. In this way, the probe body is stably fixed on the substrate by the sacrificial layer while the step b) is performed, such that potential problems of displacement and deformation of the probe body can be prevented in the cutting process. Such effect is remarkable particularly in the aforesaid cutting process for batch and mass production of the microelectromechanical probe.
Preferably, in the aforesaid method, the cutting direction is inclined relative to the probing direction at an angle. This means the at least one cut mark is inclined relative to the probing direction at the angle. As a result, in the image recognition process, when light is emitted to the pinpoint portion in a direction parallel to the probing direction and reflected by the cut mark of the cutting face, the associated reflected light will not be parallel to the probing direction. In other words, the aforesaid inclined cut mark makes the reflected light non-parallel to the incident light, thereby so effective in light extinction as to improve the image recognition in the automatic pinpoint recognition process. More preferably, the angle is larger than or equal to 45 degrees and smaller than or equal to 75 degrees so as to obtain desired effect of light extinction. However, the microelectromechanical probe of the present invention and the method of manufacturing the probe are unlimited to have the aforesaid feature. The cutting direction may be substantially perpendicular to the probing direction. This means, the at least one cut mark may be substantially perpendicular to the probing direction.
Preferably, the cutting face may be substantially shaped as one of a plane, a curved surface and a combination of multiple curved surfaces, wherein the single curved surface is optimal. For example, the cutting tool may be a ball nose milling cutter, an abrasive wheel or a form grinding wheel, for shaping the cutting face as the single curved surface by one-time processing or shaping the cutting face as the combination of multiple curved surfaces by multi-time processing. The cutting tool may be a special single-tooth or multi-tooth milling cutter, an abrasive wheel with single tapered side, or a ball nose milling cutter with relatively larger radius of curvature, for substantially shaping the cutting face as a plane.
The microelectromechanical probe of the present invention may, but unlimited to, be a straight or buckling vertical probe or a cantilever probe (also called N-shaped probe), which is formed and cut at a posture of lying horizontally. Besides, the cutting face is defined with a minimum length, which is a minimum distance measured in a direction parallel to the probing direction between the edge cut mark and the probing end, and a descending height, which is a minimum distance measured in a direction perpendicular to the probing direction between the edge cut mark and the probing end; the cutting face is preferably configured in a way that the minimum length is larger than or equal to 1.5 times of the descending height. Furthermore, in the case that the cutting face is substantially shaped as a plane, the cutting face is preferably configured to be inclined relative to the probing direction at an angle smaller than 33 degrees.
The present invention also provides a probe set including two aforesaid microelectromechanical probes, wherein the pinpoint portion of each of the microelectromechanical probes has a rear side substantially opposite to the cutting face. The rear sides of the pinpoint portions of the two microelectromechanical probes face each other. Such arrangement can make the distance between the probing ends of two adjacent probes relatively smaller, so as to satisfy the fine pitch requirement of usage.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
First of all, it is to be mentioned that same reference numerals used in the following preferred embodiments and the appendix drawings designate same or similar elements throughout the specification for the purpose of concise illustration of the present invention.
Referring to
a) As shown in
The top surface 42 and the bottom surface 41 mentioned in the present invention are named correspondingly to the state the probe is manufactured, not the state the probe is in use. The term “probing direction” used in the present invention is defined as the direction along which the probe and the DUT (not shown) are relatively moved toward each other, such that the DUT is contacted by the probing end 53 when the microelectromechanical probe 20 is used to probe the DUT. Besides, the body portion 43 of the microelectromechanical probe 20 in this embodiment includes an upper section 432 with larger width and thickness, and a lower section 434 with smaller width and thickness. The pinpoint portion 50 is extended and declines in width thereof from the bottom end of the lower section 434. However, the body portion 43 is unlimited to such configuration.
The MEMS manufacturing process mentioned in the step a) includes the steps of forming a sacrificial layer 34 (made of metal or photoresist that can be easily removed, for example) on the substrate 32 by photolithography technique and using a material, such as but unlimited to cobalt alloy (such as palladium-cobalt alloy, nickel-cobalt alloy and so on) to form the probe body 40 in the sacrificial layer 34 by electroplating. These steps of the MEMS manufacturing process belong to conventional technology well known by person having ordinary skill in the art, and therefore need not to be detailedly specified hereunder.
b) As shown in
As a result, the cutting face 54 adjoins the first side 51, the second side 52 and the probing end 53, and has at least one cut mark 542 formed by the cutting process. The at least one cut mark 542 is substantially extended from the first side 51 to the second side 52. Because the at least one cut mark 542 is produced in the cutting direction D2, it is also non-parallel to the probing direction D1. In this embodiment, the cutting tool 36 is a ball nose milling cutter, the obvious cut mark produced by which only includes an edge cut mark 542 located at an edge of the cutting face 54. The cutting face 54 descends from the edge cut mark 542 to the probing end 53. Besides, the cutting direction D2 in this embodiment is substantially perpendicular to the probing direction D1, so the cut mark 542 is substantially perpendicular to the probing direction D1.
In other words, the microelectromechanical probe of the present invention is initially formed by the MEMS manufacturing process, and then the cutting process is performed to remove a part of the initially formed pinpoint portion 50 so as to simultaneously form the cutting face 54 and cut off a part of the initially formed probing end 53. Therefore, the probing end 53 of the microelectromechanical probe of the present invention has relatively smaller area, thereby making relatively smaller probe marks upon probing the DUT, easily piercing the passivation layer of the DUT, and more recognizable in the automatic pinpoint recognition process. The cutting process mentioned in the present invention refers to any machining process which uses a cutting tool to contact a work piece directly and remove a part of the work piece, including milling, grinding, abrasive cutting and so on.
Besides, the cutting process is performed to cut the pinpoint portion 50 from the first side 51 to the second side 52 in the cutting direction D2 non-parallel to the probing direction D1. Therefore, a plurality of probes can be cut in the aforesaid way in a same cutting process. This means, as shown in
In the first preferred embodiment, the cutting face 54 is formed by one-time processing, thereby shaped as a curved surface. However, the cutting face 54 may be formed by multi-time processing to be shaped as a combination of multiple curved surfaces. Taking the microelectromechanical probe 21 according to a second preferred embodiment of the present invention as shown in
As shown in
Referring to
When the automatic pinpoint recognition process is performed subject to the microelectromechanical probe 22, light is emitted to the pinpoint portion 50 in a direction parallel to the probing direction D1. Because the cut marks 542, 544 perpendicular to the probing direction D1 are perpendicular to the light, the cut marks 542, 544 will reflect incident light back in a direction parallel to the incident light, which is liable to deteriorate the image distinguishable degree during the image recognition process. To solve this problem, a microelectromechanical probe 23 according to a fourth preferred embodiment of the present invention as shown in
The aforesaid inclined cutting process for producing the inclined cut mark is unlimited to use the abrasive wheel as the cutting tool. Taking a microelectromechanical probe 24 according to a fifth preferred embodiment of the present invention as shown in
The cutting face 54 may be shaped as a plane, such as the cutting face 54 of the microelectromechanical probe 25 according to a sixth preferred embodiment of the present invention as shown in
Referring to
Besides, the technical features of each of the aforesaid embodiments can be applied to the microelectromechanical probe 27 according to an eighth preferred embodiment of the present invention as shown in
In each of the aforesaid embodiments, the cutting face 54 is preferably configured to satisfy the following inequality.
L≧1.5H
Wherein, L is the minimum length of the cutting face 54, i.e. the minimum distance measured in a direction parallel to the probing direction D1 between the edge cut mark 542 and the probing end 53. In the case as shown in
Besides, in the case as shown in
Referring to
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
Number | Date | Country | Kind |
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104142312 | Dec 2015 | TW | national |