Search

US-12625165-B2 - Probe card

US12625165B2US 12625165 B2US12625165 B2US 12625165B2US-12625165-B2

Abstract

[Problem] The objective is to provide a probe card that are less prone to contact failure, with good high-frequency characteristics, current endurance, and good conductivity. [Solution] A probe card includes a wiring board 10 formed with one or more probe electrodes 102 , an upper guide plate 13 spaced below the wiring board 10 and facing the wiring board 10 , formed with one or more upper guide holes 131 , a lower guide plate 14 spaced below the upper guide plate 13 and facing the upper guide plate 13 , formed with one or more lower guide holes 141 , and a probe group 15 G including two or more probes 15 that are inserted through a same upper guide hole 131 and a same lower guide hole 141 and connected to a same probe electrode 102 and a same electrode 201 of an object to be inspected, wherein the probes 15 of the probe group 15 G are capable of independently each other buckling deformation between the upper guide plate 13 and the lower guide plate 14 , and their lower ends are capable of moving independently each other in a vertical direction.

Inventors

  • Chikaomi Mori

Assignees

  • JAPAN ELECTRONIC MATERIALS CORPORATION

Dates

Publication Date
20260512
Application Date
20211206

Claims (8)

  1. 1 . A probe card comprising: a wiring board formed with one or more probe electrodes; an upper guide plate spaced below the wiring board and facing the wiring board, formed with one or more upper guide holes; a lower guide plate spaced below the upper guide plate and facing the upper guide plate, formed with one or more lower guide holes; and a probe group including two or more probes that are inserted through a common upper guide hole and a common lower guide hole, each probe of the probe group directly contacting a common probe electrode and a common electrode of an object to be inspected; wherein the probes of the probe group are capable of independently each other buckling deformation in a predetermined direction between the upper guide plate and the lower guide plate, and their lower ends are capable of moving independently each other in a vertical direction, and the two or more probes of the probe group are arranged to be aligned in the predetermined direction.
  2. 2 . The probe card of claim 1 , wherein a friction reduction film is formed on a side surface of the probe.
  3. 3 . The probe card of claim 2 , wherein the lower guide hole is formed offset to the upper guide hole, and the probe in non-inspection is curved between the upper guide plate and the lower guide plate.
  4. 4 . The probe card of claim 1 , wherein the probe includes a locking part that locks onto an upper surface of the upper guide plate to prevent dislodgement from the upper guide plate, and the locking part protrudes from a needle base part at an upper part of the probe in a direction perpendicular to the predetermined direction.
  5. 5 . The probe card of claim 4 , wherein the lower guide hole is formed offset to the upper guide hole, and the probe in non-inspection is curved between the upper guide plate and the lower guide plate.
  6. 6 . The probe card of claim 1 , wherein a cross-section of an elastic deformation part is rectangular that has a short side in the predetermined direction and a long side perpendicular to the predetermined direction, the elastic deformation part being a part that buckles and deforms in the probe.
  7. 7 . The probe card of claim 6 , wherein the lower guide hole is formed offset to the upper guide hole, and the probe in non-inspection is curved between the upper guide plate and the lower guide plate.
  8. 8 . The probe card of claim 1 , wherein the lower guide hole is formed offset to the upper guide hole, and the probe in non-inspection is curved between the upper guide plate and the lower guide plate.

Description

This application is a National Stage Application of PCT/JP2021/044633, filed Dec. 6, 2021. TECHNICAL FIELD The present invention relates to a probe card, and more particularly to improvements in a probe card including vertical probes that are supported by two guide plates and generate elastic force by buckling deformation. BACKGROUND OF THE INVENTION A probe card is constituted by erecting numerous probes on a wiring board and is used as a testing device for the electrical characteristic inspection of semiconductor devices formed on semiconductor wafers. The inspection of semiconductor devices is performed by contacting the tips of the probes with electrode pads on the semiconductor wafer and conducting the semiconductor device and external devices. When inspection is performed, the probe card and the semiconductor wafer are brought close to each other, and after the probes start contacting the electrode pads, an overdrive is executed to bring the probe card and semiconductor wafer even closer. The probes elastically deform due to the overdrive, biasing them towards the electrode pads. Therefore, by ensuring a certain amount of overdrive, it is possible to absorb variations in the height of the probes and electrode pads and reliably conduct all probes with the electrode pads. Recently, with the acceleration of semiconductor devices, there is a demand for probe cards capable of performing inspections using high-frequency signals. To enhance the high-frequency characteristics of a probe card, it is necessary to shorten the length of the probes as much as possible to reduce their inductance. However, while shortening the probes and trying to ensure a certain amount of overdrive, it becomes necessary to bend the probes more significantly during overdrive. As a result, the probes may undergo plastic deformation beyond their stress limit and fail to maintain their elastic force. The maximum stress occurs on the outer side of the bent portion of the probe. Therefore, by reducing the thickness of the probe in the bending direction, it is possible to suppress the stress generated during overdrive and prevent plastic deformation. FIG. 10 illustrates a schematic diagram showing an example configuration of a conventional probe card 300. The probe card 300 includes vertical probes 15 supported by two guide plates 13 and 14. The upper end of each probe 15 is connected to a probe electrode 102 on the main substrate 10, and the lower end contacts an object to be inspected. Also, probe 15 is inserted through two guide holes 131, 141 formed in the guide plates 13, 14, which are spaced at a certain interval, allowing elastic deformation between the guide plates. The corresponding two guide holes 131, 141 are offset, allowing probe 15 to be gently curved even when not inspecting and to buckle and maintain elastic force when inspecting (for example, Patent Literature 1). FIG. 11 illustrates a schematic diagram showing an example configuration of a probe card 301 with improved high-frequency characteristics. Compared to FIG. 10, by shortening the distance between guide plates 13 and 14 and inserting shorter probes 15, it is possible to improve high-frequency characteristics. Also, by reducing the thickness of probe 15 in the buckling direction D, it can retain its elastic force during inspection even if the probe is shorter. However, reducing the thickness of probe 15 also reduces its cross-sectional area, leading to a decrease in current capacity and a new problem of reduced current endurance. Therefore, probes have been proposed where a vertically elongated slit is formed in the middle region excluding both ends, and two or more layers of plates are spaced and arranged (for example, Patent Literature 2). By providing two or more layers of plates through the slit, it is possible to increase the current capacity while suppressing plastic deformation. However, the boundary between the slit and the ends is prone to breaking due to stress concentration during elastic deformation, leading to a new problem. CITATION LIST Patent Literatures [Patent Literature 1] JP 2001-050982 A[Patent Literature 2] JP 2009-272308 A SUMMARY OF THE INVENTION Technical Problem Conventional probes have been used to establish electrical contact by touching their tips to the electrode pads of an object to be inspected. This poses a challenge when there are irregularities on the electrode pads, leading to reduced contact area, and also when tiny foreign substances on the electrode pads prevent effective contact. FIG. 12 illustrates a situation where the tip of a conventional probe 15 contacts a protrusion 202 on the electrode pad 201. When there are irregularities on the surface of electrode pad 201, the tip of probe 15 may only contact the protrusion 202, failing to ensure sufficient contact area and potentially leading to reduced current capacity. FIG. 13 illustrates a situation where the tip of a conventional probe 15 contacts a foreign substance 203 on