Patent Application
20230258689
The present application relates the field of a probe of probe card use, and a method for manufacturing the same.
A probe card is an electric connection device which is used to perform supply of electric power, input and output of signals, and grounding. For the purpose of conducting an operation test of respective semiconductor devices which are formed on a wafer, probes are made to be contacted with the electrode pads of the semiconductor device.
The probe is provided on the surface of a probe card, and constituted so that its tip may be pressed against the electrode pad of a semiconductor device with a predetermined thrust force.
In order to increase the numerical quantity of semiconductor devices formed on a wafer, reducing the size of the semiconductor devices is required. For this reason, the distance (pitch) between electrode pads is designed to be small, while the electrode pad of a semiconductor device is designed to be small.
As the semiconductor device becomes smaller, the probe needs to be made finer. However, when a finer probe is produced, there arises a problem that the mechanical strength of the probe becomes weak.
For this reason, the probe needs to ensure good electric contact and mechanical contact with the electrode pad of a semiconductor device. Then, for example, in the Patent Document 1, the configuration in which a multilayer metal sheet is used is proposed.
Patent Document 1: JP-T-2018-501490 A
The probe described in the Patent Document 1 employs, in the core, the structure by the multilayer metal sheet which is provided with a high electric conduction layer and a high hardness layer, and is completely covered with a high hardness material.
As shown in the Patent Document 1, in order to achieve good electric contact and mechanical contact, the constitution in which several layers of different materials are piled up is desirable, but there is a limit in meeting the demand for reducing the cross-sectional thickness of a probe. Then, further breakthroughs are needed.
With regard to a probe of probe card use, a probe card is further brought closer to a semiconductor wafer (overdrive), after the probe is contacted with an electrode pad. Thereby, the probe is pressed against the electrode pad of a semiconductor device, in order to ensure the contact with the electrode pad of a semiconductor device.
For this reason, the probe is required to have the strength enough to avoid the destruction, even if contact pressure larger than a predetermined value is applied to. In order to avoid the destruction of a probe, it is necessary to prevent the generation of locally concentrated stress in a probe. And, in order to prevent the generation of concentrated stress, it is required to use a probe with a smooth surface and no scratches, as much as possible.
However, there is a limit also in smoothing the surface of metal, and there arises a problem that the thinner the sectional thickness of a probe, the more easily the probe is deformed by an external force (the stress becomes smaller).
The present application is the one which discloses the technology for solving the above-mentioned problem. That is, even if a finer probe is used, the present application aims at offering the probe which is capable of contacting with a suitable stylus pressure on the electrode of a semiconductor device, and equipped with the strength which is enough to avoid the destruction, even if contact pressure larger than a predetermined value is applied to.
In other words, the probe of probe card use according to the present application is not for avoiding the generation of the concentrated stress, but the probe aims at offering a structure with large stress (high in mechanical strength), by employing the structure in which stress concentration is distributed intentionally.
A probe of probe card use which is disclosed in the present application includes
a plurality of deformation regions of hollow shape or protrusion shape, and
a framework region provided on a boundary between adjacent deformation regions,
wherein the plurality of deformation regions and the framework region are formed on a surface of the probe.
According to the probe of probe card use which is disclosed in the present application, even if the prove has a thin plate thickness, it becomes possible to offer a structure body which can have a stress larger than a predetermined value.
Hereinafter, the Embodiment 1 will be explained with reference to drawings. It is worth noticing that, in the following drawings, the same numeral is given to the same or corresponding portion.
The probe 1 which is shown in this Embodiment 1 is a probe, called a vertical probe, and is held substantially vertically by a first guide board 2 at the upper side and a second guide board 3 at the lower side. The tip portion 4 of the probe 1 is guided by the second guide board 3 so as to contact with the electrode pad 5 of a semiconductor device. The back end portion 6 of the probe 1 is guided by the first guide board 2 so as to be connected to an electrode (not shown), which joins with a circuit board of a probe card.
The probe 1 is made of thin metal plate of electric conduction material, and a plurality of deformation regions 8 and framework regions 9 is formed on the surface of the central portion 7 of this probe 1.
The deformation region 8 indicates a region in which the original plane is deformed. Moreover, the framework region 9 indicates a region which combines spaces among a plurality of deformation regions 8. Moreover, a domain which is equivalent to a ridgeline between the deformation region 8 and the framework region 9 is shown as a boundary portion 10.
In this Embodiment 1, as the deformation region 8, shown is an example in which a hollow of quadratic prism form is provided on the original plane. Moreover, the framework region 9 corresponds to a plane portion between the deformation regions 8.
Here, the following results are obtained, when comparison is made between a probe with the structure in which no deformation regions 8 are provided, and a probe with the structure in which deformation regions 8 are provided on the front face side and on the rear face side. That is, the measurement result of the probe in which no deformation regions 8 are provided on the surface is indicated as characteristic A, and the measurement result of the probe 1 in which deformation regions 8 are provided is indicated as characteristic B. Additionally, after the tip portion 4 of the probe 1 contacts with an electrode pad 5, load is further applied and the probe 1 is pressed against the electrode pad 5. In this state (overdrive state), the relation of the stylus pressure with respect to the amount of overdrive is shown in
As shown in
Factors which yielded a large maximum stress are examined. As a singular point on the structure, difference in the surface areas of the probe 1 can be considered.
That is, the hollow deformation regions 8 of quadratic prisms, which are provided on the surface of the probe 1, increased the surface area. In the case of a hollow shape where a square plane is recessed (that is, expressing a cave-in form of quadratic prism shape), the top portion of quadratic prism shape does not yield a change in the surface area, since the original surface is depressed only. On the other hand, the deformation region is increased in area by the portion of the inner wall surface, which is produced by cave-in.
In this Embodiment 1, the size of a hollow which is provided at the front side and rear side of the probe is as follows: the hollow is a quadrangle with a side length of 20 μm, the hollow depth of the front face side is set to be 3.5 μm, and the hollow depth of the rear face side is set to be 2.5 μm. At both of the front face side and the rear face side, 429 hollows of this size are provided. Those hollows increase the area of the front face side by 120120 μm2, and that of the rear face side by 85800 μm2. The surface area is increased by the area of the inner wall face of the hollow, which is produced by cave-in. Here, a hollow of large size influences the thickness of the probe 1. Then, in order to enlarge the surface area, it is desirable to attain by providing many hollows of small size. By designing the size and arrangement of these hollow shapes, the deformation region can obtain any surface area.
Furthermore, it was analyzed what kind of effect can be obtained by the deformation region 8. Probes are divided into as follows: a probe A without hollows (the form with a smooth surface), a probe B in which hollows of quadratic prism shape are arranged in a matrix like, a probe C in which hollows of quadratic prism shape are alternately arranged, and a probe D in which circular hollows are alternately arranged. Regarding those probes, the stylus pressure of the probe and the maximum stress are determined based on the Finite Element Method (FEM), and those results are as shown in Table 1.
As shown in this table 1, in the case of the probe A, the stylus pressure is 1.72 gf, when the overdrive is 70 μm, and the maximum stress is 670 MPa, when the overdrive is 110 μm. On the other hand, on the same conditions, in the case of the probe B, the stylus pressure is 1.19 gf, and the maximum stress is 891 Mpa; in the case of the probe C, the stylus pressure is 1.18 gf, the maximum stress is 899 Mpa; and in the case of the probe D, the stylus pressure is 1.18 gf and the maximum stress is 1164 Mpa.
Moreover, regarding the probe A, the probe B, the probe C, and the probe D, stress contour figures (the contour figure is a figure which indicates the calculation result by contour lines) were created. In the probe A, the stress is distributed almost uniformly, with a maximum stress of 670 MPa. In the probe B, the stress is 74 MPa in the plane part at the bottom face of the deformation region 8, and 668 MPa in the framework region 9, and the maximum stress is 891 Mpa. In the probe C, the stress is 74 MPa in the plane part at the bottom face of the deformation region 8, and 674 MPa in the framework region 9, and the maximum stress is 899 Mpa. In the probe D, the stress is 97 MPa in the sphere part at the bottom face of the deformation region 8, and 873 MPa in the framework region 9, and the maximum stress is 1164 Mpa.
From these results, it is presumed that stress is concentrated on the boundary portion 10 between the deformation region 8 and the framework region 9, when forces are applied from the outside to the probe A, the probe B, the probe C, and the probe D. Moreover, stress will be concentrated on the boundary portion 10 between the deformation region 8 and the framework region 9, when the bottom face of the deformation region 8 is made into a plane form or a sphere form.
This means that stress will be distributed on each vertex, when an external force is applied, since stress concentration will arise on each vertex of polygonal shape, when the deformation region 8 is formed by the hollow of a polygonal prism.
Therefore, if the deformation region 8 is formed by the hollows of cone shape or polygonal pyramid shape, stress can be distributed, not only on respective vertexes of the perimeter, but also on the vertexes of a cone or a pyramid.
In this case, the stress concentration which arises in the boundary portion 10 between the deformation region 8 and the framework region 9 can be reduced.
It is worth noticing that, when the boundary portion 10 is polygonal shape, stress concentration arises on each of the vertexes. However, the greater the number of corners, the smaller the stress concentration which is loaded on each of the vertexes.
From these results, when the periphery of a hollow is circular, stress would be distributed on the periphery. Then, as explained as the probe D, the structure in which sphere formed hollow shapes are provided as the deformation region 8 becomes the most effectively stress distributing structure, and it is presumed that a probe of high stress structure will be produced.
Next, explanation will be made about the method for manufacturing the probe 1, which is shown in this
As shown in
It is worth noticing that, in the Embodiment 1, explained is the structure in which the deformation region 8 is formed in hollow shape. However, also when the hollow shape is changed into the projected shape, the deformation region can acquire the same effect.
The hollow shape of the deformation region 8 in the Embodiment 1 is the hollow shape by quadratic prisms. However, in this Embodiment 2, the hollow shape of the deformation region 8 is changed into the hollow shape of triangular pyramids. In
The metal plate 73 is sandwiched by the male type metal mold 71 and the female type metal mold 72, and then, the triangular pyramid pattern 61 of hollow shape or protrusion shape can be formed on the front face and the rear face of the metal plate 73. Moreover, when forming the pattern 61 of triangular pyramids, the metal plate is stamped through at the same time. Thereby, the efficiency in the manufacturing process of the probe 1 can be improved. Especially, by performing, at one process, a pressing for a surface treatment and a stamping through of the metal plate 73, it becomes possible to manufacture the probe 1 which has the triangular pyramid pattern 61 of hollow shape or protrusion shape.
In the case of this Embodiment 2, an increase in the surface area of the deformation region 8 is the difference between the surface area of the side face of a triangular pyramid, and an area of the bottom face. When the quadratic prism pattern which is shown in
In the probe of this Embodiment 3, on the surface of the probe 1, the quadratic prism pattern of the Embodiment 1 and the triangular pyramid pattern 61 of the Embodiment 2 are combined to form a pattern. According to the probe of this Embodiment 3, the increase of surface area can be achieved in a variety of ways.
In
In this way, the whole plane can be filled with the combination of the pattern 81 of quadratic prisms and the pattern 61 of triangular pyramids.
Furthermore, it is possible to expand the area, even if the pattern is other than the combination of rectangles and triangles. For example, the area can be increased similarly, even if the pattern is a pattern of corrugated panel shape.
The probe 1 according to the Embodiment 4 is shown in
On the surface of this probe 1, the first deformation regions 91 are arranged alternately, and the second deformation regions 92 are arranged in the space between the first deformation regions 91. It is presumed that the arrangement with the first deformation region 91 and the second deformation region 92 distributes stress uniformly, and produces a probe with a high stress structure.
In the Embodiments 1 and 2, the vertical probe 1 is set as an object, and shown is the case example in which the pattern of hollow shape or protrusion shape is formed. However, as shown in
Moreover, as shown in
As a pattern of the deformation region 8, the form is assumed to be in the hollow shape or protrusion shape of polygonal prisms. In that case, a concrete example of polygonal shape is presumed to be a triangle, a quadrangle, a pentagon, and a hexagon, and further, a polygonal shape form and the like.
In the hollow shape or protrusion shape of a polygonal shape, stress concentration will arise on vertexes of the polygonal shape. And stress is distributed on each of the vertexes, according to the number of those vertexes. That is, in the case of a triangle, it is presumed that, as for the stress with respect to an external force, one third of the stress is produced on each of the vertexes.
Suppose that stress concentrates on the vertexes of a polygonal shape, and the stress is distributed according to the number of vertexes. When a circular shape is obtained by increasing the number of vertices, stress will be distributed on the whole outskirts of the circular shape. However, in order to grasp the distribution of stress and to control the stress in the optimal state, it is desirable to arrange the predetermined number of vertices at the positions defined beforehand.
Here, in this Embodiment 6, as shown in
When the hollow shape or protrusion shape of a prism of polygonal shape is set in the second deformation region 122, like in the first deformation region 121, it is desirable to provide this second deformation region 122 without a gap around the first deformation region 121. Additionally, as a prism hollow in the first deformation region 121, as shown in
When the first deformation region 121 is formed into the hollow shape of a prism of dodecagon, its circumference can be buried without a gap by the hollow shape or protrusion shape of a triangle, a quadrangle, and a hexagon. Then, it becomes possible to obtain the effect that the simulation of stress distribution can be performed easily. In addition, since the same pattern can be placed repeatedly, it becomes possible to obtain the effect that stress distribution can be made uniform.
In
As the material of the covering layer 13, resin layer, which does not interfere with the deformation of a metal plate, is desirable. Especially in the Embodiments 1-6, since a plurality of deformation regions 8 of hollow shape or protrusion shape is provided on the surface, there is a concern that a foreign substance may adhere. In order to remove that concern, the covering layer 13 for smoothing a surface is effective. The probe has a plurality of deformation regions 8 of hollow shape or protrusion shape and framework regions 9 on the surface of an electric conductor, and is provided with a covering layer 13 on the surface. Thereby, it becomes possible to obtain a probe which is high in mechanical strength and can eliminate the adhesion of a foreign substance.
As shown in
It is worth noticing that, “hollow shape or protrusion shape” means cases where only “hollow shape” is arranged, only “protrusion shape” is arranged, and “hollow shape” and “protrusion shape” are arranged.
This deformation region 8 by the hollow shape can achieve the same effect of distributing stress, even if the deformation region is changed to that of protrusion shape.
Moreover, adhesion of a foreign substance can be prevented by providing the covering layer 13 on the surface of the deformation region 8 of hollow shape or protrusion shape, like in the Embodiment 7.
Although the present application is described above in terms of various exemplary embodiments and implementations, it should be understood that the various features, aspects and functionality described in one or more of the individual embodiments are not limited in their applicability to the particular embodiment with which they are described, but instead can be applied, alone or in various combinations to one or more of the embodiments.
It is therefore understood that numerous modifications which have not been exemplified can be devised without departing from the scope of the present application. For example, at least one of the constituent components may be modified, added, or eliminated. At least one of the constituent components mentioned in at least one of the preferred embodiments may be selected and combined with the constituent components mentioned in another preferred embodiment.
1 Probe; 2 First Guide Board; 3 Second Guide Board; 4 Tip Portion; 5 Electrode Pad; 6 Back End Portion; 7 Central Portion; 8 Deformation Region; 9 Framework Region; 10 Boundary Portion; 13 Covering Layer; 41 Substrate; 42 Electric Conduction Layer; 43 Metal Layer; 51 First Metal Mold; 52 Second Metal Mold; 53 Metal Plate; 61 Pattern of Triangular Pyramids; 71 Male Type Metal Mold; 72 Female Type Metal Mold; 73 Metal Plate; 81 Pattern of Quadratic Prisms; 91 First Deformation Region; 92 Second Deformation Region; 101 Area Expanding Pattern Region; 102 Stress Concentration Region; 121 First Deformation Region; 122 Second Deformation Region; 141 First Metal Layer; 142 Second Metal Layer
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-041973 | Mar 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/009492 | 3/4/2022 | WO |
