TW201723491A - Vertical probe, probe card and method for fabricating a vertical probe - Google Patents

Abstract

A high-frequency vertical type probe is fabricated through an integrated circuit fabrication process and includes a first external conductive layer, a second external conductive layer and a middle conductive layer. The first external conductive layer is disposed opposite to the second external conductive layer, and each of the first external conductive layer and the second external conductive layer has a flexible portion and two contact portions.

Description

High-frequency vertical probe, probe card and high-frequency vertical probe manufacturing method

The present invention relates to the technical field of a probe, and more particularly to a method for fabricating a high frequency vertical probe, a probe card, and a high frequency vertical probe for electrical testing of semiconductor components.

The probe card is mainly used before the integrated circuit is packaged, and the related test instruments and software are used to perform various functional tests on the bare die by using the probe to screen out the defective products, and the good products are then subjected to the subsequent packaging process. .

As the integrated circuit process continues to evolve, the line width and spacing between circuits are shrinking, and the corresponding probe card structure is also changed. For example, the probe design in the probe card is changed from an early tip-curved, laterally placed cantilever probe to a vertical probe with a smaller needle diameter, denser, and narrower pitch. In general, the technique for fabricating a vertical probe can be roughly classified into a mechanical processing method, a chemical etching method, or a Lithographie Galvanoformung Abformung (LIGA) method, which is also fabricated by a micro-lithography deep-etching method. The probe is out of the best precision.

However, there is still room for improvement in the above manufacturing method. For example, for vertical probes produced by lithography deep etch molding, the accuracy, surface roughness and dimensional tolerance of the probes still cannot fully meet the requirements of the current bare crystal test, making the probe easy to test. Deviation from the predetermined contact position, inaccurate Balance Contact Force (BCF) or even sticky particles, which not only affects the actual measured electrical value, but also makes the electrical characteristics of each die Can not be accurately judged.

Accordingly, it would be desirable to provide an improved high frequency vertical probe, a probe card containing a high frequency vertical probe, and a method of manufacturing a high frequency vertical probe to meet the above-described deficiencies of the prior art.

In order to achieve the above object, the present invention provides an improved high frequency vertical probe, a probe card containing a high frequency vertical probe, and a method of manufacturing a high frequency vertical probe.

According to an embodiment of the present invention, a high frequency vertical probe structure is provided, which includes a first outer conductive layer, a second outer conductive layer, and an intermediate support layer fabricated by an integrated circuit process, wherein The outer conductive layer is disposed opposite to the second outer conductive layer and each has an elastic portion and two contact portions.

According to another embodiment of the present invention, a high frequency vertical probe card structure is provided, which includes a circuit board, a plurality of spacer layers, and a plurality of high frequency vertical probe structures, wherein the spacer layer is defined to accommodate high The accommodation space of the frequency vertical probe structure. Further, the high frequency vertical probe structure is fabricated by an integrated circuit process, including a first outer conductive layer, a second outer conductive layer, and an intermediate support layer, wherein the first outer conductive layer and the second The outer conductive layers are oppositely disposed and each have an elastic portion and two contact portions.

According to still another embodiment of the present invention, there is provided a method of fabricating a high frequency vertical probe comprising the following steps. First, a substrate is provided and an underlying sacrificial layer is deposited on the substrate. Then, a patterned metal layer is formed on the underlying sacrificial layer and an intermediate sacrificial layer is formed, wherein the intermediate sacrificial layer fills the gap between the patterned metal layers. Thereafter, the patterned metal layer and the intermediate sacrificial layer are repeatedly formed to form a multilayer stacked structure on the patterned metal layer. Finally, an etching process is performed to completely remove the underlying sacrificial layer and the intermediate sacrificial layer.

In the following, specific embodiments of the high frequency vertical probe, probe card and high frequency vertical probe of the present invention are set forth so that those skilled in the art can implement the present invention. The specific embodiments may be referred to the corresponding drawings, such that the drawings form part of the embodiments. Although the embodiments of the present invention are disclosed as follows, they are not intended to limit the invention, and those skilled in the art can make some modifications and refinements without departing from the spirit and scope of the invention.

Figure 1 is a schematic exploded view of a vertical probe structure in accordance with a preferred embodiment of the present invention. As shown in FIG. 1, the high frequency vertical probe structure 10 includes a first outer conductive layer 12, a second outer conductive layer 14, an intermediate support layer 16, and selectively disposed sheets 18, 20 in close contact, wherein An outer conductive layer 12, a second outer conductive layer 14, and an intermediate support layer 16 are preferably fabricated using an integrated circuit process. The high frequency vertical probe structure 10 can be preferably fabricated by an integrated circuit process compared to a vertical probe structure fabricated by a mechanical processing method, a chemical etching method, or a lithography deep etching method. The accuracy, low surface roughness and small dimensional tolerances can meet the needs of today's bare die testing. Each of the high frequency vertical probe structures 10 will be further described below to enable one of ordinary skill in the art to practice the invention.

As shown in FIG. 1, the first outer conductive layer 12 and the second outer conductive layer 14 are disposed at the outermost sides of the high frequency vertical probe structure 10, and each of them may include two contact portions 122, 124, 142, 144 and An elastic portion 120, 140. The contact portions 122, 142 and the contact portions 124, 144 may be electrically connected to external contacts, such as contact pads on the bare crystal surface, and the test device, respectively, and the elastic portions 120, 140 may be planar spring structures, which may be The appropriate flexibility is provided during the test so that the high frequency vertical probe structure 10 can be elastically deformed according to the height of the contacts on the bare crystal so that it can make close contact with the external contacts. Further, the composition of the first outer conductive layer 12 and the second outer conductive layer 14 is preferably a metal or metal alloy having high conductivity, such as beryllium copper alloy, and thus has a better electrical transmission performance. In addition, the contact portions 122, 142 may have a groove and at least two protruding ends, and the groove may be a wedge-shaped, V-shaped or U-shaped groove, and the top surface of the protruding end may be a flat surface or a circular arc convex surface. Preferably, the groove and the protruding end may have a V shape and a circular arc convex surface, respectively, but are not limited thereto.

The intermediate support layer 16 is disposed between the first outer conductive layer 12 and the second outer conductive layer 14 and has a first slider 162 and a second slider 164 that are in direct contact with each other. Each of the first slider 162 and the second slider 164 may include an inner contact portion 162a, 164a and an outer contact portion 162b, 164b such that the positions of the outer contact portions 162b, 164b may correspond to the outer conductive layers 12, 14, respectively. Contact portions 122, 142 and contact portions 124, 144. During the test, the intermediate support layer 16 can telescopically move the high-frequency vertical probe structure 10 in a certain axial direction, for example, telescopically moving along a structure perpendicular to the probe card so as not to deviate from a predetermined moving direction. Therefore, it is possible to effectively contact the external contacts. The contour of the outer contact portion 162b is preferably the same as the contour of the contact portions 122, 142. That is, the outer contact portion 162b may have a groove and two protruding ends, and the groove may be a wedge-shaped, V-shaped or U-shaped groove, and the top surface of the protruding end may be a flat surface or a circular arc convex surface. Preferably, the groove and the protruding end may have a V shape and a circular arc convex surface, respectively, but are not limited thereto. In addition, depending on the test requirements, the intermediate support layer 16 may be composed of a highly conductive metal or metal alloy, such as a beryllium copper alloy, or an insulating dielectric material such as hafnium oxide, tantalum nitride, niobium oxynitride or the like. Electrical materials, but are not limited to this.

The sheets 18, 20 may be selectively disposed between the first outer conductive layer 12 and the intermediate support layer 16 and/or between the second outer conductive layer 14 and the intermediate support layer 16, and preferably have the same contour The contours of the contacts 122, 142, 124, 144. By providing the sheets 18, 20, the rigidity of the high frequency vertical probe structure 10 can be increased, making it less susceptible to breakage during testing. Depending on the test requirements, the plates 18, 20 may be composed of a highly conductive metal or metal alloy, such as beryllium copper alloy, or an insulating dielectric material such as tantalum oxide, tantalum nitride, tantalum oxynitride or the like. Materials, but are not limited to this.

Further, when the first and second outer conductive layers 12, 14, the intermediate support layer 16, and the plates 18, 20 are all made of a conductive metal, the single high frequency vertical probe structure 10 and the outer portion can be made. The contact has a large contact area, so that its current carrying capacity can be increased; moreover, when the first and second outer conductive layers 12, 14 and the intermediate support layer 16 described above are composed of a conductive metal, the sheets 18, 20 When the composition is an insulating material, the intermediate support layer 16 can serve as a main transmission path of the electrical signal, and the first and second outer conductive layers 12, 14 can serve as a transmission path of the electrical signal or as a shielding layer. Wherein, when the first and second outer conductive layers 12, 14 are used as a shielding layer, they are preferably grounded; in addition, when the first and second outer conductive layers 12, 14 are formed of a conductive metal, the intermediate support When the composition of the layer 16 and the sheets 18, 20 is an insulating material, the first outer conductive layer 12 and the second outer conductive layer 14 can be used to output and sense electrical signals, respectively, for testing.

In addition, an anti-stick conductive layer may be selectively deposited on the outer sides of the contact portions 122, 142 of the first and second outer conductive layers 12, 14 and the outer portions of the contact portions 122, 142 of the intermediate support layer 16 according to different needs. To prevent contaminating particles from sticking to the outer sides of the contacts 122, 142 and the outer contact portion 162b during the test. The material of the adhesive conductive layer may be selected from a noble metal, preferably platinum, but is not limited thereto.

The method of fabricating the high frequency vertical probe structure 10 will be further described below. 2 is a top plan view of a photomask for fabricating a vertical probe structure according to a preferred embodiment of the present invention, and FIGS. 3 to 9 are cross-sectional views showing a vertical probe structure for fabricating a preferred embodiment of the present invention.

As shown in FIG. 3, in the initial stage of the process, a substrate 100 is first provided, and an underlying sacrificial layer 102 is formed thereon. The substrate 100 is a rigid substrate having a flat surface, and is, for example, a semiconductor substrate having a flat surface, a metal substrate, or a polymer substrate, and is preferably a single crystal germanium substrate. The underlying sacrificial layer 102 can be a metal layer or an insulating layer, preferably yttrium oxide, which serves as a dependent underlayer for the subsequent stacked structure and can be removed at the final stage of the process. Next, a metal layer 104, such as a metal or metal alloy having high conductivity, is formed on the underlying sacrificial layer 102 to completely cover the surface of the underlying sacrificial layer 102. The process of forming the metal layer 104 may include electroplating, electroless plating, sputtering, evaporation, or other suitable processes, and the composition of the metal layer 104 is preferably different from the composition of the underlying sacrificial layer 102, but is not limited thereto. .

As shown in FIG. 4, the photolithography and etching process P1 can be performed by using the mask 200 in FIG. 2 to transfer the mask pattern 12' in the mask 200 to the metal layer 104 to form a pattern. Metal layer 106. In detail, the above steps may include first coating a photoresist layer on the metal layer 104, and then transferring the mask pattern 12' to the photoresist layer by a photolithography process to form a patterned photoresist layer. The etching process is performed, the patterned photoresist layer is used as an etch mask, the pattern is further transferred into the metal layer 104, and finally the patterned photoresist layer is removed. Wherein, since the reticle pattern 12 ′ is used to define the first outer conductive layer 12 of the high-frequency vertical probe structure 10 , the planar outline of the reticle pattern 12 ′ is preferably the same as the first outer conductive layer 12 . Plane silhouette.

As shown in FIG. 5, an intermediate sacrificial layer 108 is then formed to cover the patterned metal layer 106 and fill the gap S between the patterned metal layers 106. The process of forming the intermediate sacrificial layer 108 may include spin coating, electroplating, electroless plating, sputtering, evaporation, or other suitable processes. In addition, the composition of the intermediate sacrificial layer 108 may include a conductive layer or an insulating layer, preferably the same composition as the underlying sacrificial layer 102, preferably yttrium oxide, and different from the composition of the metal layer 104. Thereafter, a planarization process can be performed such that the top surface of the intermediate sacrificial layer 108 is aligned with the top surface of the patterned metal layer 106.

As shown in FIG. 6, after planarizing the intermediate sacrificial layer 108, a material layer 110 is then formed to completely cover the patterned metal layer 106 and the intermediate sacrificial layer 108. The process of forming the intermediate sacrificial layer 108 may include spin coating, electroplating, electroless plating, sputtering, evaporation, or other suitable processes. Further, the composition of the intermediate sacrificial layer 108 may include a conductive layer or an insulating layer. Further, in order to make the top surface of the material layer 110 flatter, a planarization process may be selectively performed to further planarize the top surface of the material layer 110.

As shown in FIG. 7, the photolithography and etching process P2 can then be performed using the reticle 202 of FIG. 2 to transfer the reticle pattern 18' in the reticle 202 into the material layer 110 to 110 patterning. The reticle pattern 18' is used to define the slab 18 of the frequency vertical probe structure 10, so that the planar profile of the reticle pattern 18' is preferably the same as the planar profile of the slab 18.

Then, the integrated circuit process similar to the above may be performed multiple times, for example, multiple steps of applying photoresist, photolithography, etching, and removing photoresist, and the light in the masks 204, 206 as shown in FIG. 2 The mask patterns 16', 14' are transferred onto the patterned metal layer 106, respectively, and subjected to a suitable deposition and planarization process, such that the patterned metal layers 114, 132, and material are stacked on the patterned metal layer 106 and the material layer 110. Layer 118 and intermediate sacrificial layers 112, 116, 130, wherein patterned metal layers 114, 132 correspond to intermediate support layer 16 and second outer conductive layer 14 of frequency vertical probe structure 10, respectively. In addition, the composition of the patterned metal layers 114, 132 is preferably also a metal or metal alloy having high conductivity, and the composition of the intermediate sacrificial layers 112, 116, 130 is preferably different from the patterned metal layers 106, 114, 132 and material layers 110, 118 are more preferably cerium oxide. By selecting an appropriate material composition, in the subsequent removal process, only the intermediate sacrificial layers 112, 116, 130 can be removed without removing the patterned metal layers 106, 114, 132 and the material layer 110, 118.

As shown in FIG. 9, the process P3 is finally performed one or more times, such as a wet etching process, to simultaneously completely remove the intermediate sacrificial layers 112, 116, 130 and the underlying sacrificial layer 102, so that the high frequency vertical probe structure The substrate 100 can be completely separated to obtain a high frequency vertical probe structure 10 similar to that shown in FIG. In addition, the intermediate sacrificial layers 112, 116, 130 may also be removed first, such that the patterned metal layers 106, 114, 132 and the material layers 110, 118 are still attached to the underlying sacrificial layer 102, and then implemented, depending on the process requirements. Another removal process is to remove the underlying sacrificial layer 102, causing the high frequency vertical probe structure to completely separate the substrate 100. Wherein, in the case where the composition of the underlying sacrificial layer 102 and the intermediate sacrificial layers 112, 116, 130 is yttrium oxide, the etching solution of the wet etching process may be selected from the group consisting of diluted hydrofluoric acid (DHF), but is not limited thereto. So far, the production process of this embodiment is completed.

Since the above process for fabricating the high-frequency vertical probe structure adopts an integrated circuit process, the high-frequency vertical probe structure 10 can have better precision, lower surface roughness, and smaller dimensional tolerance, so Meet the needs of the current bare crystal test. It should be noted here that the method of the present embodiment is not limited to the fabrication of the high frequency vertical probe structure as shown in FIG. 1, which can be applied to any probe that can be fabricated through an integrated circuit process.

By the above process, a plurality of high frequency vertical probe structures 10 can be obtained simultaneously. The high frequency vertical probe structure 10 can be further assembled to obtain a probe card having a high frequency vertical probe structure 10. As shown in Fig. 10, Fig. 10 is a schematic cross-sectional view of a probe card having a high frequency vertical probe according to a preferred embodiment of the present invention. The high frequency vertical probe card 300 includes a circuit board 302, a plurality of spacers 306, and a plurality of high frequency vertical probe structures 10. The spacer 306 is fixed to the circuit board 302, and can define a plurality of independent housing spaces 308 to accommodate the high frequency vertical probe structures 10, respectively. The high-frequency vertical probe structure 10 is vertically disposed in the accommodating space 308, and the contact portions 124 and 144 at one end thereof electrically contact the signal pad 304 on the circuit board 302, and the contact portion 122 at the other end. The 142 can be in direct contact and electrically connected to the device under test 310, such as a die or circuit board having an integrated circuit layout. For example, when testing, the probe card 300 will move over the test machine, causing the probe structure 10 to directly contact the solder balls 312 on the device under test 310, which can then be applied to each probe structure 10 The signal, and/or the signal from the component to be tested 310 on each side of the probe structure 10 is used to screen out the desired component 310 to be tested. The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧High frequency vertical probe structure
12‧‧‧First outer conductive layer
12', 14', 16', 18' ‧ ‧ mask pattern
14‧‧‧Second outer conductive layer
16‧‧‧Intermediate support layer
18, 20‧‧‧ plates
100‧‧‧Substrate
102‧‧‧ bottom sacrificial layer
104‧‧‧metal layer
106, 114, 132‧‧‧ patterned metal layers
108, 112, 116, 130‧‧‧ intermediate sacrificial layer
110, 118‧‧‧ material layer
122, 124, 142, 144 ‧ ‧ contact
120, 140‧‧‧Flexible Department
162‧‧‧First slide
164‧‧‧Second slide
162a, 164a‧‧Internal contact
162b, 164b‧‧‧ External contact
200, 202, 204, 206‧‧‧ masks
300‧‧‧ probe card
302‧‧‧ boards
306‧‧‧Baffle
304‧‧‧Signal pads
308‧‧‧ accommodating space
310‧‧‧Device under test
312‧‧‧ solder balls
P1, P2‧‧‧Photolithography and etching process
P3‧‧‧Removal process
S‧‧‧ gap

Figure 1 is a schematic exploded view of a vertical probe structure in accordance with a preferred embodiment of the present invention. 2 is a top plan view of a photomask for fabricating a vertical probe structure in accordance with a preferred embodiment of the present invention. 3 to 9 are schematic cross-sectional views showing the fabrication of a vertical probe structure in accordance with a preferred embodiment of the present invention. Figure 10 is a schematic cross-sectional view of a probe card having a high frequency vertical probe in accordance with a preferred embodiment of the present invention.

100‧‧‧Substrate

102‧‧‧ bottom sacrificial layer

106, 114, 132‧‧‧ patterned metal layers

108, 112, 116, 130‧‧‧ intermediate sacrificial layer

110, 118‧‧‧ material layer

Claims (16)

A high frequency vertical probe structure comprising: a first outer conductive layer having an elastic portion and two contact portions; a second outer conductive layer disposed opposite the first conductive layer, the second outer conductive layer having An elastic portion and two contact portions; and an intermediate support layer disposed between the first outer conductive layer and the second outer conductive layer, wherein the first outer conductive layer, the second outer conductive layer, and the intermediate support The layer system is fabricated using an integrated circuit process. The high frequency vertical probe structure of claim 1, wherein the elastic portion of the first outer conductive layer and the elastic portion of the second outer conductive layer each have a planar spring structure. The high frequency vertical probe structure of claim 1, wherein the intermediate support layer comprises a first sliding member and a second sliding member, wherein the first sliding member and the second sliding member each have An inner contact portion that causes electrical contact with each other. The high frequency vertical probe structure of claim 3, wherein the first slider and the second slider each have an outer contact. The high frequency vertical probe structure of claim 4, wherein at least one contact portion of the first outer conductive layer, at least one contact portion of the second outer conductive layer, and the first sliding member The outer contacts each have a V-shaped groove. The high frequency vertical probe structure of claim 1, further comprising at least one plate disposed between the first outer conductive layer and/or the second outer conductive layer and the intermediate support layer. The high frequency vertical probe structure of claim 1, wherein the composition of the plate is a conductive material or an insulating material. A high frequency vertical probe card structure, comprising: a circuit board; a plurality of spacers disposed on the circuit board; a plurality of accommodating spaces disposed between the spacers; and a plurality of patent applications The high-frequency vertical probe structures according to the first aspect are respectively disposed in each of the accommodating spaces. A method for fabricating a high frequency vertical probe includes the steps of: (a) providing a substrate; (b) depositing an underlying sacrificial layer on the substrate; (c) forming a patterned metal layer on the underlying sacrificial layer (d) forming an intermediate sacrificial layer to fill the gap between the patterned metal layers; (e) repeating steps (c) through (d) at least once to form a multilayer stack on the patterned metal layer And (f) completely removing the underlying sacrificial layer and the intermediate sacrificial layer to obtain the high frequency vertical probe. The method for fabricating a high frequency vertical probe according to claim 9, wherein the bottom sacrificial layer and the intermediate sacrificial layer have the same composition. The method for fabricating a high frequency vertical probe according to claim 10, wherein the composition of the underlying sacrificial layer and the intermediate sacrificial layer is yttrium oxide. The method for fabricating a high frequency vertical probe according to claim 9, wherein the composition of the underlying sacrificial layer and the intermediate sacrificial layer is different from the composition of the patterned metal layer. The method for fabricating a high frequency vertical probe according to claim 9, wherein a wet etching process is utilized to completely remove the underlying sacrificial layer and the intermediate sacrificial layer. The method of fabricating a high frequency vertical probe according to claim 9, wherein the high frequency vertical probe is completely separated from the substrate after the underlying sacrificial layer and the intermediate sacrificial layer are completely removed. The method for fabricating a high frequency vertical probe according to claim 9, wherein the step (c) comprises: depositing a metal layer on the underlying sacrificial layer; and performing a photolithography and an etching process to The metal layer is patterned. The method for fabricating a high frequency vertical probe according to claim 9, wherein the step (d) comprises: depositing an intermediate sacrificial layer to cover the patterned metal layer; and performing the intermediate sacrificial layer The planarization process is such that the top surface is aligned with the top surface of the patterned metal layer.