Probe sheet with multi-stage contact tip and manufacturing method thereof

Abstract

Disclosed are: a method for manufacturing a multi-stage contact tip, which is formed on a probe sheet of a probe card for detecting a semiconductor element, and which can improve the degree of freedom in the design of a contact tip that comes into contact with a pad of the semiconductor element; and a probe sheet having a multi-stage contact tip formed thereon. In the present invention, since the probe sheet is formed on a probe card for detecting a semiconductor element, the degree of freedom of design of a contact tip in contact with a pad of the semiconductor element is improved, and in order to increase the durability of the contact tip, even if a protective layer covering the contact tip is worn out, the contact tip is prevented from being damaged. In addition, the shape of the contact surface of the contact tip is also maintained so that the contact resistance is maintained within an allowable range, and therefore, the detection reliability of the probe card can be improved.

Description

Technical Field

[0001] The present invention relates to a probe sheet formed on a probe card for testing a semiconductor element, which can improve the design freedom of a contact tip contacting a pad of the semiconductor element and has a multi-stage contact tip and a manufacturing method thereof. Background Art

[0002] Probe cards are used to detect the electrical characteristics of semiconductor components such as RF communication components. The probe card is installed on an external detection device, and the needles supported by the printed circuit board (PCB) are in contact with the semiconductor components to transmit electrical signals between the detection device and the semiconductor components. At this time, the needles supported by the probe card have the problem of difficulty in effectively contacting the miniaturized semiconductor components due to their structural characteristics.

[0003] As a prior art for coping with such a problem, in Japanese registered patent No. 3502874, a contact tip is formed by a profile in a hole formed by anisotropic etching of a silicon wafer, and the contact tip performs detection by electrical connection with an electrode of a detection object. Since the contact tip is formed in a pyramid shape corresponding to the hole based on anisotropic etching of a silicon wafer, it is difficult for the contact tip to correspond to an electrode of a narrow-pitch semiconductor element. In the document, in order to form a contact tip that directly contacts a semiconductor element, only an etching technique called anisotropic etching can be used, and therefore, the degree of freedom in designing the shape and length of the contact tip is low.

[0004] [Document 1] Japanese registered patent No. 3502874 (registered on December 19, 2003) Summary of the invention

[0005] Technical issues

[0006] The object of the present invention is to provide a probe sheet that can be formed on a probe card for detecting semiconductor elements, so as to increase the design freedom of the contact tip that contacts the solder pad of the semiconductor element, and even if the protective layer covering the contact tip to increase the durability is worn, the contact resistance can be maintained within an allowable range, thereby improving the detection reliability of the probe card by forming a probe sheet with multiple contact tips and a method for manufacturing the same.

[0007] Solutions to the problem

[0008] The probe sheet with multi-level contact tips of the present invention for achieving the above-mentioned purpose is characterized in that it includes: a ground wiring layer formed on a flexible substrate; a circuit wiring layer separated from the ground wiring layer and formed on the flexible substrate; and a multi-level contact tip having a base bump layer formed on the upper part of the circuit wiring layer of the flexible substrate and a plurality of contact tip layers stacked on the upper part of the base bump layer.

[0009] Furthermore, the present invention is characterized in that, in the multi-level contact tip, a first contact tip layer is formed on the upper portion of the base bump layer, and a second contact tip layer is formed on the upper portion of the first contact tip layer, and a cross-sectional area of ​​the second contact tip layer is formed to be smaller than a cross-sectional area of ​​the first contact tip layer.

[0010] Furthermore, the present invention is characterized in that the first contact tip layer and the second contact tip layer are shaped like quadrangular prisms.

[0011] Furthermore, the present invention is characterized in that the pedestal bump layer, the first contact tip layer and the second contact tip layer are formed of a Ni—Co alloy layer.

[0012] Furthermore, the present invention is characterized in that the multi-stage contact tip includes a protection layer, and the protection layer covers the plurality of contact tip layers in order to protect them.

[0013] Furthermore, the present invention is characterized in that the protective layer is formed of rhodium.

[0014] Furthermore, the present invention is characterized in that the flexible substrate is a polyimide layer, and the ground wiring layer is a mesh ground wire electrically connected to the circuit wiring layer.

[0015] The method for manufacturing a probe sheet having a multi-level contact tip formed therein according to the present invention for achieving the above-mentioned purpose is characterized in that it comprises: (a) a step of forming a ground wiring layer on a flexible substrate; (b) a step of forming a circuit wiring layer separated from the ground wiring layer in the flexible substrate; and (c) a step of forming a multi-level contact tip consisting of a base bump layer and a plurality of contact tip layers on the upper part of the circuit wiring layer formed in step (b).

[0016] Furthermore, the present invention is characterized by comprising a step (d) of forming a protective layer covering the outer surface of the contact layer in order to protect the contact layer formed in the step (c), wherein the protective layer is formed of rhodium.

[0017] Effects of the Invention

[0018] According to the embodiment, the degree of freedom in designing a contact tip applicable to a probe sheet is improved compared to the related art, thereby facilitating the change of the shape of the contact tip.

[0019] According to the embodiment, a multi-level contact tip is formed in a final process, and a contact is formed by photoresist film etching, electroplating, and molding processes, thereby facilitating changing the shape of the contact tip.

[0020] According to the embodiment, even if the multi-stage contact tip is worn as the number of detections using the probe card increases, resulting in a shortened tip length, the contact tip is formed into a quadrangular prism and the cross-sectional area of ​​the contact tip can be maintained constant. In this way, since the cross-sectional area of ​​the contact tip is maintained constant, the contact resistance of the contact tip allowed when designing the product can be fully satisfied, thereby improving the detection reliability of the probe card. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1a A photographic image of a probe card combined with a probe sheet having multiple contact tips according to an embodiment of the present invention.

[0022] Figure 1b is a cross-sectional view of a probe sheet having multiple contact tips according to an embodiment of the present invention,

[0023] Figure 1c is a flow chart for explaining a method for manufacturing a probe sheet having a multi-level contact tip according to an embodiment of the present invention.

[0024] Figure 2a to Figure 2k 1 is a simplified diagram sequentially showing the manufacturing process of a probe sheet having a multi-level contact tip according to an embodiment of the present invention.

[0025] Figure 3 is a photographic image of a multi-stage contact tip according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] Hereinafter, the embodiments of the present invention will be described with reference to the accompanying drawings, so as to describe the present invention. The reference numerals in the drawings indicate the same components. Furthermore, in the process of describing the present invention, if it is determined that the specific description of the relevant known functions or structures will unnecessarily confuse the gist of the present invention, the detailed description thereof will be omitted. Furthermore, when it is indicated that a certain part "includes" a certain structural element, as long as there is no special record to the contrary, it means that other structural elements may also be included without excluding other structural elements.

[0027] The probe card of the present invention is connected to a detection device and is used for detecting semiconductor elements.

[0028] The probe card of the present invention contacts the pad of the semiconductor element through the multi-stage contact tip formed on the probe sheet to sense the information of the semiconductor element. At this time, the probe card can be installed in an opening formed in a printed circuit board (PCB) to sense the information of the semiconductor element. An opening can be formed in the printed circuit board for installing the probe card, and the probe card can be installed in the opening.

[0029] like Figure 1aAs shown, the probe sheet 100 of the embodiment may be made of a flexible substrate, for example, a flexible polyimide film, and is disposed on the support portion 10 of the probe card.

[0030] A multi-level contact tip and a circuit pattern are formed on the probe sheet 100. The circuit pattern includes a ground line GND, a signal line SIG, a power line PWR, and the like.

[0031] Reference Figure 1b and Figure 1c In the probe sheet 100 having a multi-level contact tip formed in an embodiment of the present invention, a ground wiring layer 106 is formed on the polyimide layers 104 and 107, and a circuit wiring layer 110 is formed on the polyimide layer 111 on the upper portion thereof, and the multi-level contact tip 121 formed on the upper portion can be exposed (step S100), (step S200), and (step S300).

[0032] The circuit wiring layer 110 may form circuit patterns of a signal line SIG for transmitting a detection signal, a power line PWR for supplying power, a ground line GND, etc. In an embodiment, the ground wiring layer 106 forms a mesh-shaped ground wiring.

[0033] The multi-level contact tip 121 may include: a base bump layer 114, which is electrically connected to the circuit wiring layer 110 through a via; a first contact tip layer 116 and a second contact tip layer 118, which are sequentially formed on the upper portion of the base bump layer 114; and a protective layer 120, which is used to cover the outer surface of the contact tip (step S400).

[0034] Reference Figure 2a to Figure 2k A method for producing the above-mentioned probe sheet will be described.

[0035] like Figure 2a As shown, a base substrate 101 is prepared. An insulating substrate such as ceramic or glass can be used as the base substrate 101. At this time, a process of cleaning and drying the surface of the base substrate 101 to remove foreign matter attached to the base substrate may be further included.

[0036] Liquid polyimide is applied on the upper part of the base substrate 101 and cured at high temperature to form the polyimide layer 102. The high temperature curing is performed at an ambient temperature of 350°C and a process time of 1 hour, and hot air is used for drying and heat treatment.

[0037] A seed layer 103 consisting of a Ti / Cu layer 103-1 and a Cu layer 103-2 is sequentially formed on the polyimide layer 102. The Ti / Cu layer 103-1 is formed by high-temperature sputtering, and a Cu layer 103-2 having a predetermined thickness is formed on the Ti / Cu layer 103-1 by electroplating, followed by polishing to flatten the surface.

[0038] In a vacuum atmosphere, a polyimide film (PI Film) having a thickness of 12.5 μm was laminated on the seed layer 103 to form the polyimide layer 104 .

[0039] exist Figure 2b In the embodiment, the upper portion of the polyimide layer 104 is removed using an etching solution to form an etching hole 105 corresponding to the ground wiring pattern GND.

[0040] exist Figure 2c and Figure 2d In the process, a ground wiring layer 106 corresponding to the etching hole 105 is formed by a damascene process. The ground wiring layer 106 is formed by high-temperature sputtering to form a Ti / Cu layer, and a Cu layer of a predetermined thickness is formed thereon by electroplating. A polyimide layer 107 is formed on the upper part of the polyimide layer 104 and the ground wiring layer 106. The formation of the polyimide layer 107 is achieved by a bonding process of laminating a 25μm thick polyimide film (PI Film) under a vacuum atmosphere. Etching holes 108 and connection holes 109 are formed on the upper part of the polyimide layer 107. The upper part of the polyimide layer 107 is removed using an etching solution to form etching holes 108 corresponding to the signal wiring pattern (Signal), and connection holes 109 are formed by a perforation process using a laser.

[0041] like Figure 2e As shown, the circuit wiring layer 110 is formed. The circuit wiring layer 110 is formed by forming a Ti / Cu layer by high-temperature sputtering and forming a Cu layer having a predetermined thickness thereon by electroplating.

[0042] exist Figure 2f In the embodiment, a polyimide layer 111 is formed on the upper part of the polyimide layer 107 and the circuit wiring layer 110. The polyimide layer 111 is formed by a bonding process of laminating a 25 μm thick polyimide film (PI Film) under a vacuum atmosphere. An etching hole 112 and a connection hole 113 are formed on the upper part of the polyimide layer 111. The connection hole 113 is formed after the etching hole 112 is formed.

[0043] The upper portion of the polyimide layer 111 is removed using an etching solution to form etching holes 112 corresponding to the pattern of the contact tips, and the connection holes 113 are formed by a drilling process using a laser.

[0044] exist Figure 2gIn the process, a base bump layer (Base bump) 114 of the contact tip is formed. The base bump layer 114 is formed by etching the photoresist film 115 according to the pattern of the base bump, forming a Ti / Cu layer on the etched portion by high-temperature sputtering, forming a Ni-Co alloy layer of a specified thickness thereon by electroplating and molding, and performing a polishing process to flatten the surface.

[0045] exist Figure 2h The first contact tip layer 116 is formed in the process of etching the photoresist film 117 according to the pattern of the first contact tip, and forming a Ni-Co alloy layer of a predetermined thickness on the upper part of the base bump layer 114 exposed after etching by electroplating and molding, and then performing a polishing process for flattening the surface to achieve the formation of the first contact tip layer 116. The cross-sectional area of ​​the first contact tip layer 116 is formed to be smaller than the cross-sectional area of ​​the base bump layer 114.

[0046] exist Figure 2i The second contact tip layer 118 is formed by etching the photoresist film 119 according to the pattern of the second contact tip, forming a Ni-Co alloy layer of a predetermined thickness on the upper portion of the first contact tip layer 116 exposed after etching by electroplating and molding, and then performing a polishing process to flatten the surface to achieve the formation of the second contact tip layer 118.

[0047] exist Figure 2j In the process of forming the protective layer 120, a recess is formed for covering, and the exposed second contact tip layer 118 is etched around by the recess, and the protective layer 120 is covered on the outer surface of the second contact tip layer 118 by electroplating. The protective layer 120 plays a role of covering and protecting the outer surface of the second contact tip layer 118, and can be formed of a material with excellent durability. In an embodiment, the protective layer 120 is formed of rhodium with high electrical conductivity and durability.

[0048] Finally, if Figure 2k As shown, the base substrate 101, the polyimide layer 102 and the first seed layer 103 at the bottom can be removed by laser, and the photoresist films 115 and 117 at the top can be removed by a stripping process, so that a probe sheet suitable for a probe card can be manufactured.

[0049] Reference Figure 3As for the multi-level contact tip 121 of the embodiment of the present invention, on the upper part of the base bump layer 114, the first contact tip layer 116 and the second contact tip layer 118 with narrowed cross-sectional areas are in a stepped form and covered by the protection layer 120. The first contact tip layer 116 and the second contact tip layer 118 are formed into quadrangular prisms, and the cross-sectional area of ​​the second contact tip layer 118 is formed to be smaller than the cross-sectional area of ​​the first contact tip layer 116.

[0050] According to the embodiment, performance tests can be performed on various shapes of contact tips, so that the shape profile of the contact tip suitable for the semiconductor element of the inspection object can be easily obtained.

[0051] According to the embodiment, when the probe card is used, even if the multi-stage contact tip is worn and shortened in length, the cross-sectional area of ​​the contact tip formed into a quadrangular prism can be constantly maintained. The contact mark formed on the semiconductor element pressed by the contact tip is in a predetermined shape through repeated tests of the probe card, thereby confirming the wear characteristics of the contact tip. In this way, since the cross-sectional area of ​​the worn contact tip is constant, the contact resistance of the contact tip allowed when designing the product can be continuously satisfied, thereby improving the detection reliability of the probe card.

[0052] According to the embodiment, since the process of forming the coating layer on the contact tip surface by electroplating is applied, even if the thickness of rhodium is varied according to various requirements of the detection object, rhodium of a desired thickness can be formed by changing the process conditions.

[0053] The above description of the present invention is for illustrative purposes only, and a person skilled in the art will appreciate that the present invention can be easily transformed into other specific forms without changing the technical concept or essential features of the present invention.

[0054] Industrial Applicability

[0055] By using the probe card of the present invention mounted with the probe sheet having multi-stage contact tips, the electrical characteristics of a semiconductor element such as an RF communication element can be stably detected.

Claims

1. A probe sheet having a multi-stage contact tip, characterized in that: include: A ground wiring layer formed on the flexible substrate; a circuit wiring layer, separated from the ground wiring layer and formed on the flexible substrate; The multi-level contact tip has a base bump layer formed on the upper part of the circuit wiring layer of the flexible substrate and a plurality of contact tip layers stacked on the upper part of the base bump layer.

2. The probe sheet having a multi-stage contact tip according to claim 1, wherein: In the multi-stage contact tip, forming a first contact tip layer on an upper portion of the base bump layer, forming a second contact tip layer on an upper portion of the first contact tip layer, The second contact tip layer is formed to have a smaller cross-sectional area than the first contact tip layer.

3. The probe sheet having a multi-stage contact tip according to claim 2, characterized in that: The first contact tip layer and the second contact tip layer are formed as quadrangular prisms.

4. The probe sheet having a multi-stage contact tip according to claim 2, wherein: The pedestal bump layer, the first contact tip layer, and the second contact tip layer are formed of a Ni—Co alloy layer.

5. The probe sheet having a multi-stage contact tip according to claim 1, wherein: The multi-level contact tip includes a protection layer covering the plurality of contact tip layers for protecting the plurality of contact tip layers.

6. The probe sheet having a multi-stage contact tip according to claim 5, characterized in that: The protective layer is formed of rhodium.

7. The probe sheet having a multi-stage contact tip according to claim 1, characterized in that: The flexible substrate is a polyimide layer, The ground wiring layer is a mesh ground line electrically connected to the circuit wiring layer.

8. A method for manufacturing a probe sheet having a multi-level contact tip, characterized in that: include: (a) step, forming a ground wiring layer on a flexible substrate; (b) a step of forming a circuit wiring layer in the flexible substrate separately from the ground wiring layer; (c) is a step of forming a multi-stage contact tip composed of a base bump layer and a plurality of contact tip layers on the upper portion of the circuit wiring layer formed in the (b) step.

9. The method for manufacturing a probe sheet having a multi-level contact tip according to claim 8, characterized in that: The method comprises the step (d) of forming a protective layer covering the outer surface of the contact layer in order to protect the contact layer formed in the step (c), The protective layer is formed of rhodium.

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