Probe Head

Abstract

The present invention provides a probe head comprising: a body portion made of metal and having a connecting surface; a base of a predetermined height including a lower surface in contact with the connecting surface of the body portion and an upper surface opposite to the lower surface, and a probe portion including three or more contact tips provided on the upper surface to contact the electrode pad of an object to be inspected; wherein the plurality of contact tips are horn-shaped, narrowing toward the top from the bottom surface in contact with the second surface, the sum of the areas of the bottom surfaces of the three or more contact tips is 35 to 50% of the area of ​​the upper surface of the base, and the hardness is 900 Hv or higher in Vickers hardness.

Description

Technology Field

[0001] The present invention relates to probe head technology for a semiconductor test device, and more specifically, to a probe head using a MEMS (Micro Electro Mechanical Systems) process. Background Technology

[0002] Generally, semiconductor devices undergo electrical testing to verify performance and reliability after the manufacturing process is completed, and contact devices such as probe cards or test sockets are used for this purpose.

[0003] As the high integration and miniaturization of semiconductor devices have recently progressed rapidly, probe heads used in these contact devices also need to be formed with finer structures, leading to increased interest in probe heads utilizing MEMS (Micro Electro Mechanical Systems) processes.

[0004] Probe heads manufactured using MEMS technology offer the advantages of realizing fine and precise shapes and achieving a uniform structure; however, the materials and shapes generally used to achieve high hardness are brittle, leading to problems such as easy breakage or fracture due to impact and repeated contact. Furthermore, probe heads fabricated via MEMS processes are prone to interlayer burrs during stacking. These burrs increase contact resistance and degrade signal quality, significantly reducing inspection reliability. Prior art literature

[0005] Korean Patent Publication No. 10-2023-0001542 The problem to be solved

[0006] To solve the aforementioned problems, the present invention aims to provide a technology for a probe head manufactured using MEMS technology that optimizes the shape and material of the tip portion to maintain high hardness while preventing damage or breakage caused by impact during repetitive contact testing.

[0007] In addition, the purpose is to simultaneously secure excellent electrical conductivity and wear resistance, improve contact stability, and enhance adhesion stability to reduce the error rate during the testing process.

[0008] Furthermore, the purpose is to provide a MEMS probe head for semiconductor testing that enables precise contact position control, thereby providing performance suitable for testing the latest semiconductor devices with fine pitch, and improves contact stability and durability and enhances inspection reliability by ensuring high interlayer adhesion and minimizing the occurrence of burrs. means of solving the problem

[0009] A probe head according to one aspect of the present invention is characterized by comprising a body portion made of metal and having a connecting surface, a base of a predetermined height including a lower surface in contact with the connecting surface of the body portion and an upper surface opposite to the lower surface, and a probe portion including three or more contact tips provided on the upper surface and contacting an electrode pad of an object to be inspected. In this case, the plurality of contact tips are horn-shaped, narrowing toward the top from the bottom surface in contact with the upper surface, and it is preferable that the sum of the areas of the bottom surfaces of the three or more contact tips is 35 to 50% of the area of ​​the upper surface of the base.

[0010] In another aspect of the present invention, the area ratio of the area of ​​the second surface and the area of ​​the circle connecting the vertices of the three or more contact tips may be 1.7:1 to 2.4:1.

[0011] The above contact tip is a tetrahedron and preferably has a first surface formed at a first angle of inclination at the edge of the upper surface, a second surface formed at a second angle of inclination smaller than the first angle of inclination, and a third surface formed at a third angle of inclination smaller than the first angle of inclination.

[0012] At this time, the first inclination angle can be formed to be 87 to 93 degrees with respect to the upper surface.

[0013] In addition, it is preferable that the second and third inclination angles are 40 to 50 degrees with respect to the upper surface.

[0014] At this time, the sum of the second angle of inclination and the third angle of inclination can be formed to be 87 to 93 degrees.

[0015] In another aspect of the present invention, the contact tips are preferably composed of four, and a "+" shaped empty space is provided between each contact tip.

[0016] In addition, a chamfer surface with a slope that transitions along the edge between the first surface and the second or third surface may be provided.

[0017] According to one embodiment of the present invention, the probe portion has a core inside, and the core is preferably made of an alloy containing Ni.

[0018] At this time, the core may have a shape-like profile that follows the shape of the probe portion.

[0019] In addition, the alloy containing Ni is preferably one selected from the group consisting of Ni-B (nickel-boron), Ni-P (nickel-phosphorus), Ni-BW (nickel-boron-tungsten), and Ni-PW (nickel-phosphorus-tungsten).

[0020] At this time, the hardness of the core can be formed to be 700 to 1200 Hv.

[0021] In another aspect of the present invention, it is preferable that the probe head be formed on a silicon wafer by photolithography and plating processes.

[0022] In addition, the outer surface of the core may include a first layer that serves as a seed for the growth of the core on the silicon wafer.

[0023] At this time, it is preferable that the first layer be made of a Ni alloy.

[0024] According to one embodiment of the present invention, the outer surface of the first layer has an electrical conductivity of 1.0 × 10 7 S / m to 5.0×10 7 A second floor with an S / m can be provided.

[0025] At this time, it is preferable that the second layer be one selected from the group consisting of gold (Au), palladium (Pd), and rhodium (Rh).

[0026] In addition, a third layer having a hardness of 900 to 1200 Hv may be further included between the core and the first layer.

[0027] At this time, it is preferable that the third layer has a thickness of 3 to 30 μm.

[0028] In addition, the third layer is preferably selected from the group consisting of rhodium (Rh), nickel alloy (Ni-alloy), and tungsten alloy (W-alloy).

[0029] A probe pin according to another aspect of the present invention is characterized by having the probe head. Effects of the invention

[0030] The MEMS-based probe head according to the present invention maintains high hardness due to the tip shape and material configuration, while significantly improving durability against impacts occurring during repetitive contact testing, thereby significantly reducing breakage or fracture of the tip.

[0031] By forming a layered structure and thickness for hardness reinforcement, excellent electrical conductivity and wear resistance can be secured simultaneously, resulting in minimal performance degradation even after long-term use.

[0032] In addition, contact stability is improved by expanding the contact area of ​​the tip compared to the normal surface, and adhesion stability is enhanced by designing a longer tip distance, thereby reducing the error rate during the testing process.

[0033] In addition, the structural design with minimized eccentricity enables precise contact position control, providing performance suitable for testing the latest semiconductor devices with fine pitches.

[0034] Consequently, the MEMS probe head of the present invention can significantly contribute to improving the efficiency and yield of semiconductor manufacturing processes by providing superior durability, contact stability, and reliability compared to existing technologies in the electrical testing of highly integrated and miniaturized semiconductor devices. Brief explanation of the drawing

[0035] FIG. 1 is a cross-sectional view of a probe pin according to the present invention. FIG. 2 is a perspective view, a side view, and a top view of a probe head according to an embodiment of the present invention. FIG. 3 is a side cross-sectional view of a probe head according to an embodiment of the present invention. Figure 4 is a diagram comparing contact stability when in contact with a pad and a solder ball. FIG. 5 is a manufacturing process diagram of a probe head according to another aspect of the present invention. FIG. 6 is a flowchart of the manufacturing process of a probe head according to another aspect of the present invention. Figure 7 is a photograph of a probe head manufactured by the MEMS process. Specific details for implementing the invention

[0036] Before describing the invention in detail below, it should be understood that the terms used in this specification are intended to describe specific embodiments only and are not intended to limit the scope of the invention, which is limited solely by the appended claims. Unless otherwise stated, all technical and scientific terms used in this specification have the same meaning as generally understood by those skilled in the art. Throughout this specification and claims, unless otherwise stated, the terms "comprise," "comprising," and "comprising" mean including the mentioned object, step, or group of object and step, and are not used to mean excluding any other object, step, or group of object or group of step.

[0037] Additionally, in the drawings, the width, length, thickness, angle, etc., of the components may be exaggerated for convenience. The drawings are described from the observer's perspective, and when one component is described as being "above / below" or "on / below" another component, this includes not only the case where it is "immediately above / immediately below" the other component, but also the case where there is another component in between. Meanwhile, various embodiments of the present invention may be combined with any other embodiments unless explicitly stated otherwise. Any feature indicated as particularly desirable or advantageous may be combined with any other features and features indicated as desirable or advantageous.

[0038] The present invention will be described in more detail below with reference to the drawings. FIG. 1 is a cross-sectional view of a probe pin according to the present invention.

[0039] According to this, the probe pin includes a sleeve, a probe head, a lower tip, and a spring. The sleeve is a cylindrical body that protects the internal components of the probe pin and provides structural support. The probe head is located at the top of the sleeve and is a component that transmits electrical signals by making direct contact with the electrode pads or solder balls of the object under inspection.

[0040] The bottom tip is located at the bottom of the sleeve and serves to transmit signals to the external circuit by contacting a test socket or PCB pad. The spring is located inside the sleeve and provides elasticity between the probe head and the bottom tip, cushioning shock during contact and maintaining contact stability.

[0041] FIG. 2 is a perspective view, a side view, and a top view of a probe head according to an embodiment of the present invention. FIG. 3 is a side cross-sectional view of a probe head according to an embodiment of the present invention.

[0042] The probe head according to the present invention includes a body portion and a probe portion. The body portion is a part that supports the probe portion of the probe head, which will be described later, and is made of a metal material and performs the role of mechanical support and electrical signal transmission of the probe head. The body portion has a connecting surface and is connected to the base of the probe portion, which is coupled by contacting the connecting surface.

[0043] The body serves as a structural support for the probe head and is a precisely designed structure that maintains a stable connection with the probe head formed through MEMS processes and maximizes electrical characteristics and contact reliability. Its shape, length, and size may vary depending on the type or application of the probe pin, and the body is composed of a different material from the probe head.

[0044] The probe section includes a base and a contact tip. The base serves as a foundation supporting the probe section of the probe head and acts as a link between the body section and the probe section. The base has a lower surface that contacts the connecting surface of the body section and an upper surface located opposite this lower surface, and is formed to have a predetermined height. The base possesses sufficient structural strength and flatness to stably fix the probe section and effectively transmit force and pressure upon contact with the object to be inspected.

[0045] The probe portion provided on the upper surface of this base is a part that comes into direct contact with the electrode pad of the object to be inspected, and the probe portion is configured to include three or more contact tips formed on the upper surface of the base.

[0046] The contact tip has a horn shape (tetrahedron) that gradually narrows from the bottom surface in contact with the upper surface of the base toward the top.

[0047] The contact tip includes a first surface, a second surface, and a third surface depending on its shape. The first surface is a surface formed where the contact tip contacts the central region of the upper surface of the base, and is formed in a shape close to a nearly vertical surface having a large angle of inclination (θ1) of about 87 to 93 degrees relative to the upper surface of the base. This serves to increase the structural strength of the contact tip and improve durability against vertical contact pressure.

[0048] The second and third surfaces are surfaces located in the center of the upper surface of the base. Unlike the first surface, they have a relatively gentle inclination angle (θ2) of about 40 to 50 degrees relative to the upper surface of the base and extend inward. The inclination angle of the second and third surfaces is smaller than that of the first surface, and the sum of the inclination angles of the two surfaces is about 87 to 93 degrees, forming a stable tetrahedral structure that creates a wide internal space overall. Through this design, the contact tip can make stable contact with the electrode.

[0049] The height of the contact tip varies depending on the use and structure of the pin, but it is preferable that it be 90 to 120% of the height of the base, and for example, the height is 0.1 to 0.11 mm. If the above range is exceeded, the stress applied to the tip of the pin upon contact becomes excessively concentrated, which reduces structural stability and may cause problems such as breakage or accelerated wear of the tip.

[0050] On the other hand, if the above range is lowered, that is, if the height of the contact tip is lowered to less than 90% of the base height, it is difficult to secure sufficient protrusion height when in contact with the object to be inspected, making effective contact with the electrode or solder ball difficult, and problems may arise such as reduced contact stability or increased possibility of contact failure.

[0051] In addition, a chamfered surface is provided along the edge between the first surface and the second or third surface, which serves to mitigate edge brittleness upon contact, reduce breakage or current concentration during electroplating in MEMS processes, and prevent the occurrence of burrs. Furthermore, it reduces the stress concentration factor, thereby improving fatigue life by 2 to 3 times and suppressing local deformation. Additionally, the chamfer increases the contact success rate and increases the alignment tolerance.

[0052] It is desirable to form the angles formed by the chamfer surface with the first surface, the second surface, and the third surface as obtuse angles. At this time, each angle is preferably between 110 and 140°. If the angles are less than the above range, the chamfer surface is formed at an angle too acute, which significantly reduces the stress concentration relief effect, increases the occurrence of burrs due to current concentration in the acute angle portion during electroplating, and causes problems such as reduced contact stability due to slippage during contact.

[0053] In addition, the width of the chamfer surface is 0.5 to 5 μm, preferably 2.5 to 3.9 μm. If the above range is exceeded, the chamfer surface becomes excessively wide, reducing the effective contact area of ​​the contact tip and dispersing the contact pressure, which increases contact resistance and weakens the structural strength of the contact tip, making it prone to deformation or breakage. If the above range is less than, the chamfer surface becomes too narrow, resulting in insufficient stress concentration relief, and the sharpness of the corners remains, which accelerates wear of the tip tip during repeated contact and fails to effectively suppress burr generation in the MEMS process.

[0054] When the above three or more contact tips are placed on the upper surface of the base, the sum of the bottom surface areas of each contact tip is 35 to 70% of the upper surface area of ​​the base, and preferably 38 to 65%. At this time, if the above range is exceeded, the bottom surface area of ​​the contact tips becomes excessively large, causing the pressure applied upon contact to be dispersed, resulting in increased contact resistance and reduced contact stability. On the other hand, if the above range is less than, the bottom surface area of ​​the contact tips becomes too small, making it difficult to secure sufficient structural stability upon contact, which leads to accelerated wear of the tips or easy breakage of the tip tips.

[0055] In addition, the area ratio of the upper surface area of ​​the base to the area of ​​a virtual circle connecting three or more contact tip vertices is designed to be 1.7:1 to 2.4:1. Preferably, it is 1.9:1 to 2.2:1.

[0056] If the above range is exceeded—that is, if the area of ​​the circle connecting the vertices of the contact tips becomes relatively too small compared to the area of ​​the upper surface of the base—the contact tips become too densely packed in the center, narrowing the distance between the vertices. Consequently, if the position of the electrode pad or solder ball of the object under inspection is even slightly misaligned, the likelihood of contact failure increases, and a problem arises where force is concentrated at the tip ends during the contact process, making it prone to burr formation.

[0057] On the other hand, if the area of ​​the circle connecting the vertices of the contact tips becomes relatively too large compared to the area of ​​the upper surface of the base, the contact tip spacing becomes excessively wide, and thus, when contacting small electrode pads or solder balls of the object to be inspected, stable support of the tips is not achieved, resulting in unstable contact and consequently, a problem arises in which contact reliability is reduced.

[0058] Figure 4 is a diagram comparing the contact stability of the probe head when in contact with the pad and solder ball.

[0059] According to this, when the contact tip of the present invention contacts the pad, the contact point is formed at the edge of the tip, so it is shown that the likelihood of successful contact is increased even if it does not exactly match the pad.

[0060] Furthermore, when the contact tip contacts the solder ball, the contact tip of the present invention exhibits high contact stability even if there are various diameter differences of the solder ball. That is, depending on the size, the solder ball can enter and settle within the space between the contact tips to make line contact, and even if the size of the solder ball exceeds the distance between the contact tips, the long distance between the contact tips allows for easy point contact.

[0061] In contrast, the comparative examples are configured in a conical shape where the apex of the contact tip is located further inward than in the embodiment, so the possibility of contact failure is relatively high if it does not exactly align with the pad. Additionally, there is a problem in that it cannot accommodate various sizes of solder balls and it is difficult to form a stable contact.

[0062] To ensure structural stability and excellent electrical characteristics, the probe preferably includes a multilayer structure in which a first layer, a second layer, and a third layer are stacked on the outside around an internal core.

[0063] First, the core located inside the probe serves to ensure structural strength and elasticity, and is made of an alloy containing nickel (Ni). Specifically, this nickel alloy is selected from Ni-B (nickel-boron), Ni-P (nickel-phosphorus), Ni-BW (nickel-boron-tungsten), and Ni-PW (nickel-phosphorus-tungsten), and its hardness is appropriately set within the range of 700 Hv to 1200 Hv to provide high strength and elasticity simultaneously. In addition, the core is formed with a profile that follows the exact shape of the probe.

[0064] The outer surface of this core is provided with a first layer to enhance the adhesion between the second layer and the core layer. This first layer is made of a Ni alloy (e.g., Ni-P) and provides strong adhesion between the second layer and the core.

[0065] A second layer described above is formed on the outer surface of the first layer to maximize electrical conductivity, and this second layer has an electrical conductivity of 1.0 x 10 7 S / m to 5.0x10 7 It is a conductive layer with excellent characteristics.

[0066] The second layer may be composed of one selected from the group consisting of gold (Au), palladium (Pd), and rhodium (Rh), and a gold layer is preferred. This second layer improves the electrical contact performance of the probe and provides low contact resistance, thereby increasing the reliability of signal transmission.

[0067] A high-hardness third layer may be optionally included between the core and the first layer to further enhance the wear resistance and mechanical durability of the contact tip. It has a high hardness of 900 to 1200 Hv and an electrical conductivity of 1.0 × 10⁻⁶ 5 S / m to 4 × 10 7A metal with an S / m value may be used. The thickness is formed to be approximately 3 to 30 μm. The material of the third layer is different from the conductive layer, and rhodium (Rh), nickel alloy (Ni Alloy), or tungsten alloy (W Alloy) may be used, which is highly effective in preventing wear and improving durability.

[0068] Hereinafter, the process of manufacturing a probe part using the MEMS process of the probe head described above will be explained with reference to FIGS. 5a to 5i and FIG. 6.

[0069] The probe head consists of a probe portion and a body portion, with the probe portion comprising a contact tip and a base. The contact tip and base of the probe portion have internal cores made of the same material, while the material of the body portion may be the same as or different from that of the probe portion. Even when the base and body portions are made of the same material, they can be distinguished by their shape and function. Considering these structural characteristics, a precise probe portion is manufactured using a MEMS process.

[0070] An example of a process for manufacturing a probe portion of a probe head using a MEMS process includes an inverted pyramid structure forming step (1-1 mold forming step), a chamfer surface forming mold step (1-2 mold forming step), a first seed layer deposition step, a first cylindrical mold forming step (2 mold forming step), a first metal electroplating step, a first planarization and second seed layer deposition step, a second cylindrical mold forming step, a second selective second seed layer etching step, a second nickel alloy electroplating step, and a stripping and post-processing step.

[0071] Figure 5a illustrates the step of forming an inverted pyramid structure. The step of forming an inverted pyramid structure involves forming a portion to be Bulk Si Etched on a silicon wafer using photoresist, metal, or a CVD deposited film, and then forming a first-1 mold of an inverted pyramid structure through Bulk Si Etching. After wet etching using a diluted solution of KOH and HF, the remaining photoresist mask is removed using acetone, EKC, oxygen plasma, etc. Through this process, only a clean inverted pyramid structure remains, preparing a substrate for subsequent processes.

[0072] FIG. 5b illustrates the chamfer surface forming mold step. The chamfer surface forming mold step is a step of forming a special chamfer surface forming mold, the first and second molds, using a material such as photoresist or copper to fill a part of the inverted pyramid structure.

[0073] When using photoresist, liquid photoresist is applied to an inverted pyramid structure, and then UV exposure is performed through a special mask. At this time, the exposure pattern is an asymmetric pattern designed to match the shape of the contact tip, and is configured to selectively cover a portion of the inverted pyramid. This is to precisely control the specific ratios and angles of the first surface (vertical surface), the second surface, and the third surface (inclined surface). During the development process, only the exposed portion (or unexposed portion) is selectively removed. Although the method using photoresist is relatively simple and cost-effective, it requires precise temperature control due to its relatively low thermal stability during the high-temperature plating process. Additionally, precise process control is required because the shape of the chamfer surface can vary slightly depending on the thickness and degree of curing of the photoresist.

[0074] When using copper, a thin seed layer is first deposited over the entire inverted pyramid structure, and then an electroplating pattern is formed using photoresist. Subsequently, copper is selectively deposited via electroplating to fill the sides of the designed portion of the inverted pyramid. At this time, the filling is performed at an optimized ratio to match the contact tip shape, thereby forming a chamfer surface. Copper molds have the advantage of superior thermal and mechanical stability compared to photoresist, ensuring that the shape does not deform even during subsequent high-temperature processes. Additionally, the shape of the chamfer surface can be controlled more accurately by precisely controlling the electroplating time and current density. However, there are disadvantages, such as a more complex process step and the requirement of an additional etching process when removing the copper mold.

[0075] Both methods ultimately play an important role in forming a chamfer at the vertex (corner) portion, which is a slope transition region continuously formed along the edge between the first surface (vertical surface), the second surface, and the third surface (sloping surface) of the contact tip.

[0076] This chamfered surface mitigates edge brittleness upon contact, reduces breakage and current concentration during electroplating in MEMS processes, and prevents the formation of burrs. Additionally, it reduces the stress concentration factor, improving fatigue life by 2 to 3 times and suppressing local deformation. Furthermore, the chamfer increases the contact success rate and expands the alignment tolerance.

[0077] FIG. 5c illustrates the first seed layer deposition step. The first seed layer deposition step is a step of depositing a seed layer using a metal film on the front surface of a silicon wafer. The first seed layer serves as a base for forming three surfaces (first surface, second surface, and third surface) of a contact tip.

[0078] Generally, a metal with high conductivity that can be easily removed by etching when extracting the tip head is uniformly deposited to a thickness of tens to hundreds of nanometers using a sputtering or deposition method to serve as a conductive base layer for the subsequent electroplating process.

[0079] The seed layer can be composed of Ni (nickel), chromium, titanium, titanium-tungsten, etc. This layer performs the function of facilitating strong adhesion to the core and promoting the uniform growth of the subsequent plating layer.

[0080] Preferably, the metal layer structure of the first seed layer can be formed as a two-layer structure of a titanium layer and a copper layer. The titanium layer ensures bonding strength, while the copper layer ensures electrical conductivity. At this time, the height ratio of the titanium layer to the copper layer is preferably 1:7 to 1:12. If the above range is exceeded, the titanium layer becomes relatively too thin, resulting in reduced adhesion to the silicon substrate and causing delamination during subsequent processes; if the above range is below, the ratio of the copper layer is low, which not only fails to ensure sufficient electrical conductivity but also causes a problem where the efficiency of the etching process for removing the first seed layer in the final stage is reduced.

[0081] FIG. 5d illustrates the first-stage cylindrical mold formation step. The first-stage cylindrical mold formation step involves forming a second mold, which is a first-stage cylindrical mold, on top of an inverted pyramid through a photolithography process. This pattern defines the base portion of the probe and serves as a mask for the subsequent plating process. After applying photoresist, a pattern is formed at an accurate position and size through exposure and development processes. This process is an important step that determines the basic structure of the probe head.

[0082] FIG. 5e illustrates a first-stage metal electroplating step. The first-stage metal electroplating step involves first electroplating a third layer on a first seed layer, followed by plating a core. The third layer is formed with a thickness of approximately 3 to 30 μm by selecting one of rhodium (Rh), Ni Alloy, W Alloy, or the alloy thereof, and has a high hardness of 900 to 1200 Hv.

[0083] The core is made of an alloy containing nickel (Ni), specifically selected from Ni-B (nickel-boron), Ni-P (nickel-phosphorus), Ni-BW (nickel-boron-tungsten), and Ni-PW (nickel-phosphorus-tungsten), with the hardness appropriately set in the range of 700 Hv to 1200 Hv. This core material is applied identically to the contact tip and base to provide structural consistency. The plating temperature is 40°C to 80°C, and the current is carried out in the range of 0.5 ASD to several tens of ASD; as the plating fills the pyramid, the material and characteristics of the contact tip end are determined.

[0084] Figure 5f illustrates the first-stage planarization and second-stage seed layer deposition steps. The first-stage planarization and second-stage seed layer deposition steps involve precisely planarizing the height of the first-stage cylindrical pattern through a Chemical Mechanical Polishing (CMP) process and depositing a new seed metal layer, the second-stage seed layer, upon it. Through this process, the surface of the first-stage structure is smoothed and adjusted to an accurate height. The new second-stage seed layer deposited after planarization serves as a conductive base layer for forming the second-stage structure and improves interlayer adhesion. Similar to the first-stage seed layer, a two-layer structure consisting of a titanium layer and a copper layer is preferred for the second-stage seed layer as well.

[0085] FIG. 5g illustrates the step of forming a two-stage cylindrical mold. The step of forming a two-stage cylindrical mold involves applying photoresist onto a newly deposited seed metal and forming a third mold, which is a mold with a two-stage cylindrical structure. This pattern defines the upper structure of the probe and is precisely laminated onto the first-stage structure. Accurate alignment is achieved through a photolithography process, and the shape and size of the two-stage structure are determined according to the pattern formed in this step.

[0086] FIG. 5h illustrates a two-stage selective second seed layer etching step. The two-stage selective second seed layer etching step is a step for selectively removing the seed metal in areas without a photoresist pattern. This process ensures that metal is deposited only in the desired areas during subsequent plating. The exposed seed metal is removed using a wet etching method, and the photoresist acts as a mask to protect the seed metal beneath the pattern. This process is an important step for improving the precision and selectivity of the two-stage plating.

[0087] After Fig. 5h, a side seed metal deposition step may be optionally added. In this step, an additional seed metal layer is formed on the side of the structure to improve plating uniformity and adhesion. Electroless plating or oblique angle sputtering methods are mainly used, which results in a more uniform current distribution and increased filling at the corners. While this process improves plating quality, it also has disadvantages such as increased process complexity and higher costs. Therefore, it is applied selectively considering the required performance and productivity of the probe head.

[0088] Figure 5i illustrates a two-stage nickel alloy electroplating step. The two-stage nickel alloy electroplating step is a step of electroplating a nickel alloy onto a two-stage cylindrical structure through the remaining second seed layer.

[0089] Subsequently, stripping and post-processing steps are performed. This step involves removing the organic film and metal mold after the total height formation is completed via final CMP, and then removing the silicon wafer using chemicals to separate the probe portion of the final probe head. During separation, the probe head, consisting of a nickel alloy core and a second layer, is separated, and the first and second seed layers do not remain after the MEMS process.

[0090] Subsequently, a first layer is applied to the front surface of the outer surface of the probe head on the core layer (if the third layer is not formed) or the third layer (if the third layer is formed), and a second layer is plated on the front surface of the first layer. Accordingly, the first layer acts as a seed layer for plating the second layer, and the second layer is a layer formed on the outer surface of the first layer after the probe part and the body part are combined, and a conductive layer such as gold (Au), palladium, or rhodium is separately formed in a subsequent process to maximize electrical conductivity.

[0091] If necessary, heat treatment (100℃~400℃, 1~4 hours) is performed to increase the hardness of the contact tip, and depending on the purpose, the final physical properties of the probe part are optimized through vacuum, N2 atmosphere, or rapid cooling treatment.

[0092] The contact tip forms three surfaces including a first surface (vertical surface), a second surface, and a third surface (inclined surface), and a probe part having a precise tetrahedral structure having a chamfer surface, which is an inclined transition region continuously formed along the edge between the first surface and the second surface or the third surface, is finally completed.

[0093] The probe part manufactured in this way is subsequently combined with the body part to form a probe head. After being combined with the body part, a second layer is formed on the outer surface as a conductive layer to maximize electrical conductivity. The second layer is selected from gold (Au), palladium (Pd), and rhodium (Rh), and preferably, a gold layer is used. The conductive layer has an electrical conductivity of 1.0 x 10⁻⁶ 7 S / m to 5.0x10 7 It has excellent characteristics, improves the electrical contact performance of the probe part, and provides low contact resistance, thereby increasing the reliability of signal transmission.

[0094] The body may be formed from the same material as the probe or a different material, and even when made of the same material, it is distinguished by its shape and function. The body primarily serves as a structural support for the probe head and is connected to the base of the probe to optimize the stability and electrical characteristics of the entire probe head.

[0095] Meanwhile, Fig. 6 is a photograph of a probe head manufactured by the aforementioned MEMS process.

[0096] The features, structures, effects, etc. exemplified in each of the aforementioned embodiments can be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong.

Claims

Claim 1 A body part made of metal and having a connecting surface; and a base of a predetermined height including a lower surface in contact with the connecting surface of the body part and an upper surface opposite to the lower surface, and a probe part including three or more contact tips provided on the upper surface and in contact with the electrode pad of the object to be inspected; wherein the plurality of contact tips are horn-shaped, narrowing toward the top from the bottom surface in contact with the upper surface, and the sum of the areas of the bottom surfaces of the three or more contact tips is 35 to 70% of the area of ​​the upper surface of the base, the probe part has a core inside, a first layer is provided on the outer surface of the core, and a second layer is provided on the outer surface of the first layer, the core has a hardness in the range of 700 Hv to 1200 Hv, the first layer is a layer for increasing the adhesion force of the second layer to the core, and the second layer is one selected from the group consisting of gold (Au), palladium (Pd), and rhodium (Rh), and between the core and the first layer, the core has a hardness of 900 to A probe head comprising a third layer of high hardness of 1200 Hv, wherein the core and the third layer are laminated by a MEMS process, and the first layer and the second layer are formed by plating after the MEMS process. Claim 2 In claim 1, the contact tip is a tetrahedron, and the probe head has a first surface formed at a first angle of inclination at the edge of the upper surface, a second surface formed at a second angle of inclination smaller than the first angle of inclination, and a third surface formed at a third angle of inclination smaller than the first angle of inclination. Claim 3 A probe head according to claim 2, wherein the area ratio of the area of ​​the second surface to the area of ​​the circle connecting the vertices of the three or more contact tips is 1.7:1 to 2.4:

1. Claim 4 In paragraph 3, the probe head having a first inclination angle of 87 to 93 degrees with respect to the upper surface. Claim 5 In paragraph 3, the probe head wherein the second and third inclination angles are 40 to 50 degrees with respect to the upper surface. Claim 6 A probe head according to claim 5, wherein the sum of the second inclination angle and the third inclination angle is 87 to 93. Claim 7 A probe head according to claim 1, wherein the contact tips are composed of four, and a "+" shaped empty space is provided between each contact tip. Claim 8 A probe head according to paragraph 2, having a chamfered surface in which the slope transitions along the edge between the first surface and the second or third surface. Claim 9 In claim 1, the probe head has a core inside, and the core is made of an alloy containing Ni. Claim 10 delete Claim 11 In claim 9, the above-mentioned Ni-containing alloy is a probe head selected from the group consisting of Ni-B (nickel-boron), Ni-P (nickel-phosphorus), Ni-BW (nickel-boron-tungsten), and Ni-PW (nickel-phosphorus-tungsten). Claim 12 delete Claim 13 delete Claim 14 delete Claim 15 In claim 1, the probe head having a first layer made of Ni alloy. Claim 16 In item 15, the outer surface of the first layer has an electrical conductivity of 1.0 x 10 7 S / m to 5.0x10 7 A probe head equipped with a second layer. Claim 17 In claim 16, the second layer is a probe head selected from the group consisting of gold (Au), palladium (Pd), and rhodium (Rh). Claim 18 delete Claim 19 In claim 1, the third layer is a probe head having a thickness of 3 to 30 μm. Claim 20 In claim 1, the third layer is a probe head selected from the group consisting of rhodium (Rh), nickel alloy (Ni-alloy), and tungsten alloy (W-alloy). Claim 21 A probe pin having the probe head of claim 1.

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