Method for manufacturing crown tip structure using MEMS process, and crown tip structure manufactured by the same

Abstract

The present invention relates to a crown tip structure used in a semiconductor test probe and a method for manufacturing the same. The manufacturing method of the present invention comprises forming a polymer pattern using a photolithography process within a single pyramid-shaped groove formed by etching on a substrate, and filling the remaining space without the polymer pattern with a conductive material to form a crown tip structure having multiple tips. Unlike conventional technology, which required forming a groove for each tip, the present invention allows for the free fabrication of multi-tip structures of various shapes from a single groove. This effectively disperses stress generated upon contact with a semiconductor terminal, thereby improving the durability of the probe, simplifying the process, and increasing design freedom.

Description

Technology Field

[0001] The present invention relates to a crown tip structure used in a semiconductor test probe, and more specifically, to a method for manufacturing crown tip structures of various shapes using a MEMS (Micro-Electro-Mechanical Systems) process and a crown tip structure manufactured by said method. Background Technology

[0002] In order to test the electrical characteristics of a semiconductor device, a probe that stably connects the test equipment and the terminals of the semiconductor device is essential. The part located at the end of such a probe that comes into direct contact with the terminals of the semiconductor device is called a contact tip.

[0003] The shape of this contact tip can be manufactured in various ways depending on the test subject, one of which is a crown tip consisting of several pointed ends like a crown.

[0004] MEMS processes are widely used to precisely manufacture such contact tips. A number of prior art documents (e.g., Patent Documents 1 to 4 below) commonly disclose a basic method of forming a tip by forming a pyramid-shaped groove (mold) on a substrate (mainly silicon) by wet etching and filling the groove with a conductive metal material (e.g., plating).

[0005] However, the tip formation methods of these prior art technologies all have a fundamental limitation in that a single pyramid-shaped groove forms a single solid tip, and the pyramid-shaped groove formed during the initial etching process directly determines the shape of the final tip. In other words, they fail to present a method for fabricating a new tip shape different from the etched shape, such as a multi-tip structure advantageous for stress distribution, by dividing or deforming the space inside the groove. Prior art literature

[0006] 1. Korean Published Patent No. 10-2019-0001738 2. Korean Registered Patent No. 10-1286722 3. Korean Registered Patent No. 10-1047550 4. Korean Published Patent No. 10-2009-0132215 The problem to be solved

[0007] The present invention was devised to solve the problems of the aforementioned prior art.

[0008] In other words, the purpose is to provide a new method for manufacturing a crown tip structure that utilizes a pyramid-shaped groove formed by initial etching merely as an external frame and forms a precise polymer pattern inside it using a photolithography process, thereby allowing the detailed shape of the tip to be freely controlled as intended without being restricted by the basic shape of the groove.

[0009] In addition, the present invention has another objective of providing a new crown tip structure capable of improving the reliability and lifespan of a probe by implementing a multi-tip structure optimized for dispersing stress applied to a semiconductor terminal through the above method. means of solving the problem

[0010] To achieve the above-mentioned objective, the present invention provides a method for manufacturing a crown tip structure using a MEMS (Micro-Electro-Mechanical Systems) process, comprising: (a) etching a silicon substrate having a (100) crystal plane to form at least one pyramid-shaped groove; (b) forming a polymer pattern that fills a portion of the space inside the groove; (c) forming a crown tip by filling a conductive material into the space not filled by the polymer pattern within the groove; and (d) removing the polymer pattern while leaving the crown tip intact.

[0011] In addition, the above method is characterized in that step (c) is one of electroplating, electroless plating, sputtering, or thermal evaporation.

[0012] In addition, the method is characterized in that the etching in step (a) above is anisotropic wet etching.

[0013] In addition, the present invention provides a method characterized in that the polymer pattern is formed through a photolithography process.

[0014] Additionally, the method is characterized in that the groove in step (a) is a single groove, and the polymer pattern in step (b) is a pattern that covers the center of the single groove.

[0015] Additionally, the method is characterized in that the grooves of step (a) are a plurality of grooves, and the polymer pattern of step (b) is a pattern that covers the inner edge of each of the plurality of grooves and exposes the outer edge.

[0016] Additionally, the method is characterized in that the grooves of step (a) are a plurality of grooves, and the polymer pattern of step (b) is a pattern that exposes the inner edge of each of the plurality of grooves and covers the outer edge.

[0017] Additionally, the method is provided in which the grooves of step (a) are a plurality of adjacent grooves, and the polymer pattern of step (b) is in a form in which the central region where the plurality of grooves meet is open.

[0018] In addition, the present invention provides a crown tip structure comprising a plurality of individual tips, wherein the outer surface of each individual tip forms part of a single pyramid-shaped inclined surface, and the inner surface of each individual tip is formed vertically.

[0019] In addition, the present invention provides a crown tip structure comprising a plurality of individual tips, wherein each individual tip is pyramid-shaped and has an asymmetric shape in which an inner edge portion facing the center is vertically cut.

[0020] In addition, the present invention provides a crown tip structure comprising a plurality of individual tips, wherein each individual tip is pyramidal in shape, but has an asymmetrical shape in which the outer edge portion far from the center is vertically cut. Effects of the invention

[0021] The manufacturing method according to the present invention and the structure manufactured thereby have the following effects.

[0022] First, by freely designing the polymer pattern formed inside the etched groove, a wide variety of final tip shapes, the number of individual tips, and their positions can be realized. This overcomes the limitations of conventional technology, where the initial etched shape determined the final tip shape, thereby providing groundbreaking design freedom.

[0023] Second, multiple tips can be freely arranged in a form optimized for stress distribution, which minimizes damage to semiconductor terminals and increases the reliability of the probe.

[0024] Third, according to one embodiment of the present invention, when multiple tips are formed from a single groove, the process is simplified compared to the conventional technology in which multiple fine grooves had to be etched individually, and it is possible to integrate the tips at a high density. Brief explanation of the drawing

[0025] FIG. 1 is a flowchart showing the steps of an integrated crown head manufacturing process according to one embodiment of the present invention. FIGS. 2a to 2j are drawings for specifically explaining the manufacturing process of FIG. 1. FIG. 3 is a perspective view of an integrated crown head having a crown tip structure according to one embodiment of the present invention. Figure 4 is a diagram showing a comparison of stress analysis simulation results between a crown tip according to the present invention and a conventional crown tip. FIG. 5 is a perspective view of an integrated crown head having a crown tip structure according to another embodiment of the present invention. Figure 6 is a drawing for explaining a method of manufacturing the crown tip structure of Figure 5. FIG. 7 is a perspective view of an integrated crown head having a crown tip structure according to another embodiment of the present invention. Figure 8 is a drawing for explaining a method of manufacturing the crown tip structure of Figure 7. FIG. 9 is a perspective view of an integrated crown head having a crown tip structure according to another embodiment of the present invention. Figure 10 is a drawing for explaining a method of manufacturing the crown tip structure of Figure 9. FIG. 11 is a perspective view of an integrated crown head having a crown tip structure according to another embodiment of the present invention. Figure 12 is a drawing for explaining a method of manufacturing the crown tip structure of Figure 11. FIGS. 13 and 14 are perspective views of an integrated crown head having a crown tip structure according to another embodiment of the present invention. Specific details for implementing the invention

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. However, embodiments of the present invention may be modified in various different forms, and the scope of the present invention should not be interpreted as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the art. Accordingly, the shapes of elements in the drawings are exaggerated to emphasize clearer explanations, and elements indicated by the same reference numeral in the drawings represent the same elements.

[0027] The present invention relates to a novel method for manufacturing a crown tip structure used at the tip of a semiconductor test probe. The core of the present invention lies in forming a precise polymer pattern using a photolithography process within a single pyramid-shaped groove formed by an etching process, and using the groove and the empty space created by this pattern as a mold to finally form a crown tip structure having multiple tips.

[0028] FIG. 1 is a flowchart of a method for manufacturing a crown tip structure according to an embodiment of the present invention, and FIGS. 2a to 2j are drawings for explaining each step.

[0029] Hereinafter, with reference to FIGS. 1 and FIGS. 2a to 2j, a method for manufacturing a crown tip structure according to an embodiment of the present invention will be described in detail.

[0030] First, the pyramid-shaped groove formation step (S100) is described.

[0031] The first step of the present invention is to form a basic frame that determines the external shape of the crown tip, namely, a pyramid-shaped groove.

[0032] Referring to FIG. 2a, a substrate (10) is prepared first. In a preferred embodiment of the present invention, the substrate (10) is a silicon (Si) substrate having a (100) crystal plane. This is because the (100) silicon substrate is very advantageous for forming a predictable and precise V-groove or pyramid-shaped cavity in an anisotropic wet etching process.

[0033] When a substrate (10) is prepared, an etching mask layer, such as an oxide film (SiO2) or a nitride film (Si3N4), is formed on its surface, and an area to be etched is opened through a photolithography process. Then, anisotropic wet etching is performed using an etching solution such as KOH (potassium hydroxide) or TMAH (tetramethylammonium hydroxide).

[0034] As illustrated in FIGS. 2b and 2c, as etching proceeds, a natural etch-stop phenomenon occurs where the {111} crystal plane, which is hardly etched due to the difference in etching speed according to the crystal direction of silicon, is exposed. As a result, a pyramid-shaped groove (20) with a constant inclination angle (about 54.7 degrees) is precisely formed in the substrate (10).

[0035] After the formation of the groove (20) is completed, the oxide film (SiO2) or nitride film (Si3N4) used as an etching mask layer for the formation of the groove (20) is removed.

[0036] Afterwards, to form a seed layer for a subsequent plating process, a metal layer such as Ti / Cu can be deposited on the front surface of the substrate (10) using a metal deposition method such as sputtering or thermal evaporation.

[0037] Next, the polymer pattern formation step (S200) is described.

[0038] In this step, a polymer pattern (30) is formed inside the pyramid-shaped groove (20) formed in the previous step. This step is a key step of the present invention for determining the internal shape of the crown tip to be finally obtained, that is, a plurality of tip structures.

[0039] As shown in FIG. 2d, a photosensitive polymer, such as a photoresist (PR) (30a), is first applied to the entire substrate (10) in which the groove (20) is formed, by a method such as spin coating.

[0040] Then, referring to FIGS. 2e and 2f, light is selectively exposed using a photomask (not shown) designed with a pattern corresponding to the space between the multiple tips to be finally formed. As an exposure method, a maskless method in which a UV laser is directly irradiated onto the PR surface may be used. Afterward, when the photoresist in the unnecessary area is removed through a development process, a polymer pattern (30) of a precise shape remains that fills a portion of the space inside the pyramid-shaped groove (20). This polymer pattern (30) functions as a sacrificial structure to prevent the conductive material from being filled in the subsequent process.

[0041] Since the planar shape of the polymer pattern (30) defines the internal empty space of the final tip structure, it can be freely designed in various shapes such as square, circular, elliptical, and cross shapes depending on the design of the photomask. Additionally, the polymer pattern (30) may be designed as a pattern with an opening formed in the center, such as a square, circular, elliptical, or cross shape.

[0042] In addition, the area of ​​the polymer pattern (30) becomes a key variable for controlling the relative distance between the individual tips that are ultimately formed. For example, if the area of ​​the square or circular polymer pattern is small, the space filled with the conductive material extends to the center of the groove, so the individual tips are placed close to each other. Conversely, if the area of ​​the polymer pattern is large, it occupies most of the center of the groove, so the conductive material is filled only in the narrow space at the periphery, and the individual tips are placed far apart from each other along the edges of the groove. By adjusting the shape and area of ​​the polymer pattern in this way, the geometric characteristics of the crown tip can be precisely controlled to suit the purpose.

[0043] Next, the conductive material filling step (S300) is described.

[0044] In this step, the remaining empty space inside the groove (20) that is not filled by the polymer pattern (30) is filled with a conductive material (40) to form the body of the crown tip.

[0045] As shown in FIGS. 2g and 2h, a conductive material (40) is filled into the empty space excluding the polymer pattern (30). Various metal deposition methods, such as electroplating, electroless plating, sputtering, or thermal evaporation, can be used to fill the conductive material.

[0046] As for the conductive material (40) to be filled, nickel (Ni), nickel alloys such as nickel-cobalt (Ni-Co), nickel-tungsten (Ni-W), nickel-boron (Ni-B), or rhodium (Rh) may preferably be used, but are not limited thereto, considering the high hardness, wear resistance, and excellent electrical conductivity required for the contact tip.

[0047] Next, the polymer pattern removal step (S400) is described.

[0048] When the filling of the conductive material (40) is complete, the polymer pattern (30) that defined the internal shape of the crown tip is removed.

[0049] As illustrated in FIGS. 2i and 2j, only the polymer pattern (30) inside is selectively removed while leaving the crown tip formed of the conductive material (40) intact. A wet removal method using a specific stripper solution suitable for the polymer material, or a dry removal method such as ashing using plasma, may be used.

[0050] When this step is completed, only the crown tip structure (40) of the desired multi-tip shape remains inside the pyramid-shaped groove (20) of the silicon substrate (10).

[0051] The manufacturing of the basic crown tip structure of the present invention is completed through the above steps S100 to S400. Subsequently, if necessary, a head body is integrally formed on the crown tip structure (40) through an additional process, and finally, the silicon substrate (10) is removed to complete the final product.

[0052] FIG. 3 is a perspective view of an integrated crown head having a crown tip structure according to one embodiment of the present invention.

[0053] As described above, the crown head (50) comprises a crown tip structure (40) including a plurality of triangular pyramidal individual tips (41) and a head body (52) integrally formed at the lower part thereof. In this embodiment, the crown tip structure (40) is composed of four individual tips (41) protruding from the upper surface of the head body (52).

[0054] The shape and arrangement of each individual tip (41) are determined by the shape of the polymer pattern (30). In this embodiment, it can be seen that four separate individual tips (41) are formed from one pyramid groove using a square polymer pattern (30).

[0055] The outer surface of each individual tip (41) forms part of a single pyramid-shaped inclined surface, and the inner surface of each individual tip (41) is formed vertically.

[0056] Figure 4 is a diagram showing a comparison of stress analysis simulation results between a crown tip according to the present invention and a conventional crown tip.

[0057] That is, this is a drawing showing the results of simulating the stress applied to the head body through Finite Element Analysis when the crown tip according to the present invention and the crown tip according to the prior art (having four individual pyramid-shaped tips) come into contact with the terminal (Ball) of a semiconductor device.

[0058] As illustrated, the structure of the conventional technology on the right shows high stress (von-Mises stress) of up to 30.9 MPa concentrated in specific areas, whereas the design according to the present invention on the left shows a maximum stress of approximately 17.9 MPa, which is half the level. This means that the multi-tip structure of the present invention effectively disperses the force generated upon contact, thereby significantly reducing the mechanical burden applied to the head body. Therefore, the crown tip structure according to the present invention has the effect of reducing mechanical fatigue of the probe and improving overall durability and lifespan.

[0059] FIG. 5 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention, and FIG. 6 is a drawing for explaining a method of manufacturing the crown tip structure of FIG. 5.

[0060] This embodiment differs from the embodiment shown in FIG. 3 in the position of the individual tip (41') of the crown head (50').

[0061] As illustrated in FIG. 6, in this embodiment, a polymer pattern (30') with a larger area is formed during the photolithography process. As a result, each individual tip (41') that is finally formed is spaced further apart from each other. Thus, the present invention has the advantage of being able to precisely and freely control the geometric arrangement of individual tips (41') simply by changing the design of the polymer pattern.

[0062] FIG. 7 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention, and FIG. 8 is a drawing for explaining a method of manufacturing the crown tip structure of FIG. 7.

[0063] While the previously described embodiments involved forming multiple tips using a single groove, the present embodiment relates to a method of controlling the shape of the final tip by using multiple grooves and forming a polymer pattern inside each groove.

[0064] First, a silicon substrate (10) is prepared in the same manner as in the previous embodiment (100). Then, an etching mask with four separate regions open is formed through a photolithography process. When anisotropic wet etching is performed using this mask, four independent pyramid-shaped grooves (70) are formed on the substrate (10), as shown in FIG. 8 (a).

[0065] Next, a photosensitive polymer, such as photoresist (PR), is applied to the entire substrate (10) as in the previous embodiment. Then, patterning is performed using a photomask so that the polymer remains only in the area corresponding to the inner corner of each groove (70).

[0066] As a result, as illustrated in FIG. 8(b), a polymer pattern (72) occupying the center is formed inside each of the four grooves (70). That is, the polymer pattern (72) covers the inner corners of each of the four grooves (70) and exposes the outer corners. The inner corners are the corners closest to the center between the four grooves (70), and the outer corners are the corners furthest from the center.

[0067] Next, the remaining space inside the groove (70) that is not filled by the polymer pattern (72), that is, the edge area of ​​each groove, is filled with a conductive material.

[0068] After all processes are completed and the substrate (10) and polymer pattern (72) are both removed, a crown tip structure (80) consisting of four independent individual tips (82) is finally completed, as shown in FIG. 7. Each individual tip (82) has a pyramid shape, but is an asymmetric shape in which the inner edge portion facing the center is vertically cut.

[0069] This embodiment embodies the same technical concept of the present invention in that, although multiple grooves (70) are formed, the inside of each groove is controlled again with a polymer pattern, thereby enabling the production of a tip with a shape modified for the purpose rather than a simple pyramid shape.

[0070] FIG. 9 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention, and FIG. 10 is a drawing for explaining a method of manufacturing the crown tip structure of FIG. 9.

[0071] While previous embodiments used a rectangular pillar-shaped polymer pattern to fill the inside of the groove, this embodiment is characterized by using a polymer pattern (92) with a circular opening to form a more complex and functional tip structure.

[0072] The manufacturing process is as follows.

[0073] First, as shown in (a) of FIG. 10, anisotropic wet etching is performed on a silicon substrate (10) (100) to form four pyramid-shaped grooves (90) separated from each other.

[0074] Next, a photosensitive polymer (PR) is applied to the entire substrate (10), and then a photolithography process is performed. The photomask used at this time has a pattern in which only a small area corresponding to the inner corner of each of the four grooves (90) is opened in a circular shape, and all other areas including the outer corner are blocked.

[0075] When the development process is finished, as shown in FIG. 10 (b), most of each groove (90) is covered with a polymer pattern (92), and only the inner edge portion facing the center is exposed. For example, a single polymer pattern (92) in the shape of an annular (donut or tube) can be used that covers all four grooves (90) while exposing only the inner edge portion of each groove (90).

[0076] Next, a conductive material is filled only into the very small inner corner space exposed by the polymer pattern (92).

[0077] After all processes are completed and the substrate (10) and polymer pattern (92) are removed, a crown tip structure (100) consisting of four separate tips (102) is finally completed, as shown in FIG. 9. Each tip (102) has a shape that precisely replicates only the inner vertex portion of the pyramid groove. Each individual tip (102) is pyramid-shaped, but has an asymmetrical shape in which the outer edge portion far from the center is vertically cut.

[0078] FIG. 11 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention, and FIG. 12 is a drawing for explaining a method of manufacturing the crown tip structure of FIG. 11.

[0079] The present embodiment is characterized by forming a plurality of grooves and then controlling the filling of a conductive material only in the center where the grooves meet to form a single integrated tip with multiple tip surfaces combined.

[0080] First, anisotropic wet etching is performed on a silicon substrate (100) to form four pyramid-shaped grooves (110) adjacent to each other with respect to a central point, as shown in (a) of FIG. 12.

[0081] Through a photolithography process, as shown in FIG. 12 (b), the outer parts of the four grooves (110) are all covered, and a polymer pattern (112) is formed in which only the center where the grooves (110) meet is open in a square shape.

[0082] Next, a conductive material is filled only in the square space of the center that is uniquely open by the polymer pattern (112).

[0083] After all processes are completed, the substrate (10) and the polymer pattern (112) are removed, and finally, a crown tip structure (120) as shown in FIG. 11 is completed.

[0084] FIG. 13 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention. The crown tip structure (140) of this embodiment can be manufactured using a polymer pattern having a pattern in which only a small area corresponding to the inner corner of each of the four grooves is opened as a square rather than a circle, and all other areas are blocked, as in the embodiment shown in FIG. 9 and 10.

[0085] FIG. 14 is a perspective view of an integral crown head having a crown tip structure according to another embodiment of the present invention. In the embodiment shown in FIG. 11 and 12, the crown tip structure (160) of the present embodiment can be obtained by expanding only the area of ​​the open central part of the polymer pattern.

[0086] Although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the invention as claimed in the claims, and such modifications should not be understood individually from the technical spirit or perspective of the present invention. Explanation of the symbols

[0087] 10: Substrate 20, 70, 90, 110: Pyramid-shaped grooves 30, 30', 72, 92, 112: Polymer pattern 30a: Photoresist 40, 80, 100, 120, 140, 160: Crown tip structure 41, 41', 82, 102: Individual tips 50, 50': Crown head 52: Head body

Claims

Claim 1 A method for manufacturing a crown tip structure using a MEMS (Micro-Electro-Mechanical Systems) process, comprising: (a) etching a silicon substrate having a crystal plane (100) to form a single groove in the shape of a pyramid; (b) forming a polymer pattern covering the center inside the single groove; and (c) filling a space not filled by the polymer pattern within the single groove with a conductive material to form a crown tip comprising four separate tips corresponding to each corner region of the single groove, wherein the outer surface follows the inclined plane of the pyramid shape and the inner surface follows the sidewall of the polymer pattern. Claim 2 A method for manufacturing a crown tip structure according to claim 1, wherein step (c) is one of electroplating, electroless plating, sputtering, or thermal evaporation. Claim 3 A method for manufacturing a crown tip structure according to claim 1, characterized in that the etching in step (a) is anisotropic wet etching. Claim 4 A method for manufacturing a crown tip structure according to claim 1, characterized in that the polymer pattern is formed through a photolithography process. Claim 5 A method for manufacturing a crown tip structure according to claim 1, characterized in that, after step (a), a step of depositing a metal layer on the front surface of a silicon substrate having a single groove formed thereon is performed. Claim 6 A method for manufacturing a crown tip structure according to claim 5, wherein the step of depositing the metal layer is a step utilizing a metal deposition method such as sputtering or thermal evaporation. Claim 7 A method for manufacturing a crown tip structure according to claim 1, further comprising, after step (c), step (d) removing the polymer pattern while leaving the crown tip intact.

Images