TWI834270B - Probe card structure and method of manufacturing same - Google Patents

Abstract

A probe card structure and a method of manufacturing same are disclosed. The probe card structure includes a connecting board and a plurality of coaxial transmission structures. The connecting board includes a first substrate provided with a plurality of conductive through holes, and a second substrate. Each of the coaxial transmission structures includes an embedded section and an extension section extending from the embedded section. The embedded section is embedded in the corresponding conductive through hole and electrically contacts a conductive layer of the conductive through hole. Width of the embedded section in a horizontal direction is less than width of the extension section in the horizontal direction, and one end of the extension section is fixed on the second substrate, so that a transmission path of the probe card is optimized.

Description

Probe card structure and manufacturing method

The present invention relates to the technical field of electrical testing, and in particular, to a probe card structure and a manufacturing method thereof.

Integrated circuits (ICs) must be tested by a test system before or after packaging. In addition to screening good products, various electrical characteristics parameters can also be obtained to establish device models for circuit design, thereby improving products. market competitiveness. The probe card serves as the connection medium between the electronic component under test and the test system, so that the test system can transmit test signals to the electronic component through the probe card.

The current probe card includes an upper board, a lower board and a plurality of coaxial cables arranged between the upper and lower boards. The upper board is a circuit board and has a plurality of via holes for burying conductive pillars. The lower board The board supports the plurality of coaxial cables. One end of each coaxial cable is welded to one end of the corresponding conductive post, and the other end is welded to the lower plate, wherein the other end of the conductive post is electrically connected to the automatic testing machine. In other words, the signal transmission path of the traditional probe card is that the automatic test machine first contacts the conductive posts in the upper board, then connects the coaxial cables outside the upper board through the conductive posts, and finally connects through the coaxial cables by soldering. Conductive pillars and lower plates in the upper plate. It can be seen that the above-mentioned signal transmission path has undergone multiple interface conversions, resulting in multiple impedance discontinuities. Furthermore, the coaxial cable and the conductive posts are different objects, and the solder at both ends of the coaxial cable and the conductive posts in the upper board are discontinuous transmission paths, so the signal transmission path of the coaxial cable is split into ground- The signal line-ground (GSG) is welded at three points on the upper and lower boards, which causes the transmission characteristics to deteriorate, increases the loss of the signal transmission path, and creates multiple impedance discontinuities.

One object of the present invention is to provide a probe card structure and a manufacturing method thereof to improve the signal path loss of the traditional probe card and reduce impedance discontinuities, thereby optimizing the signal transmission quality.

In order to achieve the above object, the present invention provides a probe card structure, which includes a connecting plate and a plurality of coaxial transmission structures. The connecting board includes a first substrate and a second substrate. The first substrate includes a plurality of conductive vias, respectively penetrating two opposite surfaces of the first substrate, and a conductive layer is provided on the wall of each conductive via hole. Each coaxial transmission structure includes an embedded section and an extension section extending from the embedded section. The embedded section is buried in the corresponding conductive through hole and electrically contacts the conductive layer. The width of the embedded section in a horizontal direction is smaller than the width of the extended section in the horizontal direction. One end of the extended section is fixed on the third Two substrates.

Preferably, the coaxial transmission structure further includes a central conductor, an insulating tube covering the central conductor, and a metal layer covering the insulating tube, wherein the central conductor, the insulating tube and the metal layer are respectively along the The embedded section and the extension section are provided, and the extension section also includes an outer sleeve. One end of the outer sleeve closes one end of the conductive through hole and is close to a surface of the first substrate. .

Preferably, an end of the conductive via hole away from the second substrate is provided with a first metal pad, and the first metal pad connects the metal layer of the coaxial transmission structure and the conductive layer of the conductive via hole. The coaxial transmission structure is electrically connected to a test equipment.

Preferably, the end of the conductive via hole away from the second substrate is further provided with an annular groove, the annular groove is disposed along the edge of the conductive via hole, and the conductive layer extends into the annular groove, wherein The first metal bonding pad is disposed in the annular groove, and a portion of the embedded section is exposed to the annular groove and a surface of the first substrate, and is connected to the first metal bonding pad.

Preferably, the conductive layer of the conductive via hole is disposed along the entire wall surface of the conductive via hole.

Preferably, the second substrate includes a holding surface provided with a plurality of second metal pads for electrically connecting the extension sections of the coaxial transmission structures.

Preferably, the diameter of the conductive via hole is smaller than the width of the extension section in the horizontal direction.

The present invention also provides a method for manufacturing a probe card structure. At least one conductive through hole is formed on a first substrate, wherein the conductive through hole penetrates the opposite surface of the first substrate; and a conductive through hole is formed in the conductive through hole. layer; provide at least a coaxial transmission structure, wherein the coaxial transmission structure includes a coaxially arranged central conductor, an insulating tube, a metal layer, and an outer sleeve, and remove part of the outer sleeve of the coaxial transmission structure, using To form an embedded section, the metal layer is exposed to the outside, and other parts of the coaxial transmission structure form an extended section with the outer sleeve; the embedded section of the coaxial transmission structure is buried in the conductive through hole, so that The metal layer located in the embedded section contacts the conductive layer of the conductive via hole, and the extended section is exposed outside the first substrate; forming a first metal pad at one end of the conductive via hole; and providing a second substrate, wherein The second substrate includes a holding surface, and a second metal pad is formed on the holding surface. One end of the extension section away from the conductive via hole is connected to the second metal pad, so that the second substrate holds the Coaxial transmission structure.

Preferably, before the step of forming the first metal pad, it also includes forming an annular groove at the end of the conductive via hole away from the second substrate, the annular groove being along the edge of the conductive via hole is arranged, and the conductive layer extends into the annular groove. The first metal pad is disposed in the annular groove, so that the metal layer located in the embedded section of the probe card structure and the conductive layer of the conductive via hole are fitted and fixed to each other.

Preferably, the width of the embedded section in a horizontal direction is smaller than the width of the extension section in the horizontal direction, and the aperture of the conductive via hole is smaller than the width of the extension section in the horizontal direction.

In the probe card structure and its manufacturing method provided by the present invention, the outer sleeve is removed from the embedded section of the coaxial transmission structure, and is directly embedded in the conductive through hole, and is in contact with the first metal pad, and the coaxial transmission structure One end of the extended section is fixed to the second metal pad of the second substrate, so that the coaxial transmission structure forms a direct and continuous signal transmission path between the test equipment and the object under test, and the signal transmission path does not pass through another signal transmission path in the middle. The conversion of the interface reduces impedance discontinuities, thereby optimizing the overall electrical characteristics and improving signal transmission efficiency. It effectively solves the problem that the signal transmission path of the traditional probe is split into ground-signal line-ground (GSG) three points welded on the upper board and The lower board will cause the transmission characteristics to deteriorate, increase the loss of the signal transmission path, and produce multiple impedance discontinuities.

In order to make the purpose, technical means and effects of the present invention clearer and clearer, the present invention will be further described in detail below with reference to the drawings and examples. It should be understood that the specific embodiments described here are only used to explain the present invention. The word "embodiment" used in the description of the present invention is meant to be used as an example, illustration or illustration, and is not intended to limit the present invention. Furthermore, the article "a" or "a" used in the description of the present invention and the appended claims may generally be construed to mean "one or more" unless otherwise specified or the singular form is clear from the context. Furthermore, in the accompanying drawings, elements with similar or identical structures and functions are represented by the same element numbers.

The present invention is a probe card structure that serves as a connection medium between electronic components to be tested (such as wafers or chips, etc.) and test equipment, so that the test equipment can transmit test signals to tiny electronic components through the probe card structure. , and then test and extract the electrical characteristics of the electronic component. Specifically, the probe card structure of the present invention can be used for preliminary testing or final testing of 5G communication devices or high-frequency and high-speed related devices at the stage of unpackaged IC or packaged IC.

Please refer to FIGS. 1 and 2 . FIG. 1 is a schematic diagram of the three-dimensional structure of the probe card structure 100 of the present invention. FIG. 2 is a schematic diagram of the use state of the probe card structure of the present invention. As shown in FIGS. 1 and 2 , the probe card structure 100 of the present invention includes a connecting plate 1 and a plurality of coaxial transmission structures 2 . The connecting board 1 includes a first substrate 11 and a second substrate 12 . The first substrate 11 is specifically a circuit board, including a plurality of conductive vias 110 arranged at intervals (FIG. 1 only uses a single conductive via and a single coaxial transmission structure as an example). Each conductive via 110 penetrates the opposite top surface 11 a and the bottom surface 11 b of the first substrate 11 respectively. Specifically, the wall surface of the conductive via 110 is formed by a conductive layer 111 . Preferably, the conductive layer 111 is disposed along the entire wall of the conductive via 110 to increase the contact area, and is made of a metal with good conductivity (such as copper, nickel, gold, palladium, etc.). The side of the first substrate 11 away from the second substrate 12 is electrically connected to a testing device 3 (as shown in FIG. 2 ). The second substrate 12 includes a holding surface 121 for holding a plurality of coaxial transmission structures 2 , and the side of the second substrate 12 opposite to the holding surface 121 is used for contacting an object under test 4 (such as a wafer or chip, etc.) for testing. Test (shown in Figure 2).

Continuing to refer to FIG. 1 , the coaxial transmission structures 2 are arranged corresponding to the conductive through holes 110 , and each coaxial transmission structure 2 is divided into an embedded section 201 and an extension section 202 extending from the embedded section 201 . Specifically, in the embedded section 201 and the extended section 202, each coaxial transmission structure 2 includes a central conductor 21, an insulating tube 22 covering the central conductor 21, and a metal layer 23 covering the insulating tube 22, and extends Section 202 also includes an outer sleeve 24. As shown in Figure 1, the coaxial transmission structure 2 of the present invention is a coaxial probe structure. The central conductor 21 is a metal probe, which can be a rod-shaped structure and can be made of metal with good conductivity and flexibility. The insulating tube 22 can be made of a material with good insulation (or low dielectric constant), and the insulating tube 22 is easy to flex. The metal layer 23 is made of a metal with good conductivity (such as copper, nickel, gold or palladium, etc.), and is coated on an outer edge surface of the insulating tube 22 to form a mesh metal layer, and is electrically connected to the central conductor 21 isolate.

As shown in FIGS. 1 and 2 , the outer sleeve 24 of the present invention is only provided along the extension section 202 , and the coaxial transmission structure 2 is not provided with an outer sleeve 24 in the embedded section 201 . That is, in the transverse cross-section, the width of the embedded section 201 in a horizontal direction is smaller than the width of the extension section 202 in the horizontal direction, and the aperture of the conductive through hole 110 is smaller than the width of the extension section 202 in the horizontal direction, so as to facilitate subsequent The assembly of the coaxial transmission structure 2 and the first substrate 11 . The outer sleeve 24 can be made of a material with good insulation (or low dielectric constant) to protect the coaxial transmission structure 2 and provide a shielding effect for the internal metal layer 23 to prevent signal transmission from external interference.

Please continue to refer to Figures 1 and 2. Specifically, the embedded section 201 of the coaxial transmission structure 2 is embedded in the corresponding conductive through hole 110, so that the metal layer 23 located in the embedded section 201 directly contacts the conductive material in the conductive through hole 110. The layer 111 is electrically connected, and the central conductor 21 extends out of the conductive via 110 . As shown in Figure 1, one end of the outer sleeve 24 closes one end of the conductive through hole 110 and is close to the bottom surface 11b of the first substrate 11, so that the embedded section 201 is properly supported by the outer sleeve 24 of the extended section 202, and more It is ensured that the signal transmission of the coaxial transmission structure 2 in the conductive through hole 110 is not interfered by external factors. In addition, one end of the extension section 202 away from the conductive through hole 110 is fixed on the holding surface 121 of the second substrate 12 (as shown in FIG. 2 ).

As shown in FIG. 1 , a first metal pad 113 is provided at an end of the conductive via 110 away from the second substrate 12 . Specifically, the first metal pad 113 is disposed on the top surface 11a of the first substrate 11 and connects the metal layer 23 of the coaxial transmission structure 2 and the conductive layer 111 of the conductive via 110 to electrically connect the coaxial transmission structure 2 and Test equipment 3 (shown in Figure 2). In addition, the holding surface 121 of the second substrate 12 is provided with a plurality of second metal pads 122 for electrically connecting the extension sections 202 of the coaxial transmission structures 2 . It is worth mentioning that the conductive layer 111 of the conductive via 110 can be used as an outer conductor corresponding to the center conductor 21 and can be grounded together with the ground plane of the first substrate 11 . In addition, the conductive vias 110 combined with the peripheral mesh metal layer 23 of the central conductor 21 enable good conduction in the first substrate 11 in the form of coaxial transmission, which not only shortens the overall signal path but also reduces impedance discontinuities.

Please continue to refer to Figures 1 and 2. The embedded section 201 of the coaxial transmission structure 2 of the present invention removes the outer sleeve 24, is directly embedded in the conductive through hole 110, and is in contact with the first metal pad 113, while the extension section 202 One end is fixed to the second metal pad 122 of the second substrate 12, so that the coaxial transmission structure 2 forms a direct and continuous signal transmission path between the test equipment 3 and the object under test 4, and the signal transmission path does not pass through another signal transmission path in the middle. The conversion of an interface will not cause discontinuity in impedance, thereby effectively optimizing the overall transmission path and improving signal transmission efficiency and quality.

Please refer to FIG. 4D first. It is worth noting that in order to ensure a stable connection between the coaxial transmission structure 2 and the first substrate 11 , an annular groove 112 is also provided on the top surface 11 a of the conductive via 110 away from the second substrate 12 . Specifically, the annular groove 112 is provided along the hole edge of the conductive through hole 110 and is formed concavely toward the second substrate 12 so that part of the embedded section 201 of the coaxial transmission structure 2 is exposed to the annular groove 112 and the first substrate. 11 a, and the conductive layer 111 extends into the annular groove 112 . As shown in FIG. 4D , the annular groove 112 is welded with a metal material 113 a (such as tin) to fill the annular groove 112 , thereby forming a part of the first metal pad 113 in the annular groove 112 and the other part of the first metal pad 113 in the annular groove 112 . A metal pad 113 is exposed on the top surface 11 a of the first substrate 11 . Utilizing the cooperation between the annular groove 112 and the first metal pad 113, the metal layer 23 of the coaxial transmission structure 2 located in the embedded section 201 and the conductive layer 111 of the conductive via 110 are fitted and fixed to each other.

Please refer to FIG. 3 and FIG. 4A-4E. FIG. 3 is a flow chart of the manufacturing method of the probe card structure of the present invention. FIG. 4A-FIG. 4E are schematic flow charts of the manufacturing process of the intermediate product corresponding to the probe card structure of the present invention. As shown in Figure 3, the manufacturing method of the probe card structure of the present invention includes steps S10 to S60. However, the steps S10 to S60 are used to illustrate the manufacturing method of the present invention and do not represent the manufacturing of the probe card structure of the present invention. Fixed order of methods.

In step S10: forming at least one conductive via hole on a first substrate, wherein the conductive via hole penetrates the opposite surface of the first substrate. Specifically, as shown in FIG. 4A , a plurality of conductive vias 110 are formed on the first substrate 11 using a hole forming process (FIG. 4A only takes one conductive via as an example), where the conductive vias 110 penetrate the first substrate 11 The opposite top surface 11a and bottom surface 11b.

In step S20: forming a conductive layer in the conductive via hole. Specifically, as shown in FIG. 4A , the conductive layer 111 is formed on the wall surface of the conductive via hole 110 by electroplating, chemical plating, evaporation, etc.

In step S30: provide at least a coaxial transmission structure, wherein the coaxial transmission structure includes a coaxially arranged central conductor, an insulating tube, a metal layer, and an outer sleeve, and remove part of the outer sleeve of the coaxial transmission structure , to form an embedded section so that the metal layer is exposed to the outside, and other parts of the coaxial transmission structure form an extension section with the outer sleeve. Specifically, as shown in FIG. 4B , multiple coaxial transmission structures 2 are provided. Each coaxial transmission structure 2 includes a central conductor 21 , an insulating tube 22 covering the central conductor 21 , and a metal layer 23 covering the insulating tube 22 . , and an outer sleeve 24 covered with the metal layer 23, and part of the outer sleeve 24 of the coaxial transmission structure 2 is removed to form an embedded section 201, so that the metal layer 23 is exposed to the outside, and other parts of the coaxial transmission structure 2 Partially formed is an extension 202 having an outer sleeve 24 . Specifically, the width of the embedded section 201 in a horizontal direction is smaller than the width of the extension section 202 in the horizontal direction, and the aperture of the conductive via 110 is smaller than the width of the extension section 202 in the horizontal direction.

In step S40: bury the embedded section of the coaxial transmission structure in the conductive through hole, so that the metal layer located in the embedded section contacts the conductive layer of the conductive through hole, and the extended section is exposed outside the first substrate. Specifically, as shown in FIG. 4C , the embedded section 201 with the outer sleeve 24 removed is embedded in the conductive through hole 110 , so that the metal layer 23 covering the insulating tube 22 contacts the conductive layer 111 of the conductive through hole 110 , and the extended section 202 is exposed outside the bottom surface 11 b of the first substrate 11 .

In step S50: form a first metal pad at one end of the conductive via hole. Specifically, before the step of forming the first metal pad 113 and after forming the conductive via 110, it also includes forming an annular groove 112 (such as shown in Figure 4A). Specifically, the annular groove 112 is provided along the edge of the conductive via 110 , and the conductive layer 111 extends into the annular groove 112 . Referring to FIG. 4D, a metal material 113a (such as tin) is soldered in the annular groove 112 to fill the annular groove 112, thereby forming a part of the first metal pad 113 in the annular groove 112, and another part of the first metal pad 113 in the annular groove 112. The metal pad 113 is exposed on the top surface 11 a of the first substrate 11 .

In step S60: Provide a second substrate, wherein the second substrate includes a holding surface, and a second metal pad is formed on the holding surface, and an end of the extension section away from the conductive via hole is connected to the second Metal pads enable the second substrate to hold the coaxial transmission structure. Specifically, as shown in FIG. 4E , a second substrate 12 is provided as a carrying substrate, and the second substrate 12 includes a holding surface 121 . A second metal pad 122 is formed on the holding surface 121 , and one end of the extension section 202 of the coaxial transmission structure 2 is connected to the holding surface 121 so that the second substrate 12 holds the coaxial transmission structure 2 .

To sum up, in the probe card structure and its manufacturing method provided by the present invention, the embedded section of the coaxial transmission structure removes the outer sleeve and is directly buried in the conductive through hole and contacted with the first metal pad. , and one end of the extended section of the coaxial transmission structure is fixed to the second metal pad of the second substrate, so that the coaxial transmission structure forms a direct and continuous signal transmission path between the test equipment and the object under test, and the signal transmission path is in the middle It no longer needs to be converted through another interface, reducing impedance discontinuities, thereby optimizing the overall electrical characteristics and improving signal transmission efficiency, effectively solving the problem that the signal transmission path of the traditional probe is split into three points: ground - signal line - ground (GSG). Welding on the upper and lower boards will cause the transmission characteristics to deteriorate, increase the loss of the signal transmission path, and produce multiple impedance discontinuities.

The above embodiments are used to illustrate the technical idea of the present invention, but not to limit the technical idea of the present invention. Therefore, the scope of rights of the present invention is not limited to this embodiment. The protection scope of the present invention should be interpreted by the claims, and it should be interpreted that all technical ideas that are the same or equivalent to the above protection scope are included in the right scope of the present invention.

100:Probe card structure 1:Connection board 11: First substrate 11a: Top surface 11b: Bottom surface 110:Conductive via 111: Conductive layer 112: Annular groove 113: First metal pad 113a: Metallic materials 12:Second substrate 121: Holding surface 122: Second metal pad 2: Coaxial transmission structure 21:Center conductor 22:Insulation tube 23:Metal layer 24:Outer bushing 201: Embedded segment 202:Extended section 3:Test equipment 4:Object to be tested S10: Steps S20: Steps S30: Steps S40: Steps S50: Steps S60: Steps

Figure 1 is a schematic three-dimensional structural diagram of the probe card structure of the present invention. Figure 2 is a schematic diagram of the probe card structure in use according to the present invention. FIG. 3 is a flow chart of the manufacturing method of the probe card structure of the present invention. 4A-4E are schematic diagrams of the manufacturing process of the probe card structure of the present invention.

100:Probe card structure

1:Connection board

11: First substrate

11a: Top surface

11b: Bottom surface

110:Conductive via

111:Conductive layer

113: First metal pad

12:Second substrate

121: Holding surface

122: Second metal pad

2: Coaxial transmission structure

21:Center conductor

22:Insulation tube

23:Metal layer

24:Outer bushing

201: Embedded segment

202:Extended section

Claims (6)

A probe card structure includes: a connecting board, including a first substrate and a second substrate, wherein the first substrate includes a plurality of conductive through holes, respectively penetrating two opposite surfaces of the first substrate, and each The wall surface of the conductive via hole is provided with a conductive layer, and an end of the conductive via hole away from the second substrate is provided with a first metal pad and an annular groove. The annular groove is along the edge of the conductive via hole. is provided, and the conductive layer extends into the annular groove; and a plurality of coaxial transmission structures, each coaxial transmission structure includes an embedded section, an extension section extending from the embedded section, and a central conductor, a coaxially arranged Insulating tube, a metal layer, and an outer sleeve, wherein the embedded section is buried in the corresponding conductive through hole and electrically contacts the conductive layer, and the width of the embedded section in a horizontal direction is smaller than that of the extended section in the The width in the horizontal direction, one end of the extension section is fixed to the second substrate, wherein the central conductor, the insulating tube and the metal layer are respectively arranged along the embedded section and the extension section, and the extension section also includes an outer sleeve, One end of the outer sleeve closes one end of the conductive via hole and is close to a surface of the first substrate; wherein the first metal pad connects the metal layer of the coaxial transmission structure and the conductive layer of the conductive via hole, It is used to electrically connect the coaxial transmission structure and a test equipment, and the first metal pad is provided in the annular groove, and part of the embedded section is exposed to the annular groove and the other surface of the first substrate , and connected to the first metal pad. The probe card structure as claimed in claim 1, wherein the conductive layer of the conductive via hole is disposed along the entire wall surface of the conductive via hole. The probe card structure of claim 1, wherein the second substrate includes a holding surface provided with a plurality of second metal pads for electrically connecting the extension sections of the coaxial transmission structures. The probe card structure of claim 1, wherein the aperture of the conductive through hole is smaller than the width of the extension section in the horizontal direction. A method for manufacturing a probe card structure, including: forming at least one conductive via hole on a first substrate, wherein the conductive via hole penetrates two opposite surfaces of the first substrate; forming a conductive layer in the conductive via hole ; Provide at least a coaxial transmission structure, wherein the coaxial transmission structure includes a coaxially arranged central conductor, an insulating tube, a metal layer, and an outer sleeve, and remove part of the outer sleeve of the coaxial transmission structure to An embedded section is formed so that the metal layer is exposed to the outside, and other parts of the coaxial transmission structure form an extended section with the outer sleeve; the embedded section of the coaxial transmission structure is buried in the conductive through hole, so that the coaxial transmission structure is located in the conductive through hole. The metal layer of the embedded section contacts the conductive layer of the conductive via hole, and the extended section is exposed outside the first substrate; a first metal pad is formed at one end of the conductive via hole; and a second substrate is provided, wherein the The second substrate includes a holding surface, and a second metal pad is formed on the holding surface. One end of the extension section away from the conductive via hole is connected to the second metal pad, so that the second substrate holds the coaxial Transmission structure; wherein before the step of forming the first metal pad, it also includes forming an annular groove at the end of the conductive via hole away from the second substrate, the annular groove along the edge of the conductive via hole disposed, and the conductive layer extends into the annular groove, wherein the first metal pad is disposed in the annular groove In the groove, the metal layer located in the embedded section of the probe card structure and the conductive layer of the conductive via hole are fitted and fixed to each other. The manufacturing method of a probe card structure as claimed in claim 5, wherein the width of the embedded section in a horizontal direction is smaller than the width of the extension section in the horizontal direction, and the aperture of the conductive via hole is smaller than the width of the extension section in the horizontal direction. The width of the direction.