Electroplated nickel micromachined probes with out-of-plane predeformation for IC chip testing

Abstract

This paper presents a new type of electroplated nickel micromachined probe with out-of-plane predeformation for next generation integrated circuit (IC) chip testing probe card applications. The probe card was fabricated using silicon bulk micromachining, titanium (Ti) deposition, nickel (Ni) electroplating and laser scribing processes. We use the effect of the residual stresses of thin-film deposition on flexible micromachined probes to produce a large out-of-plane predeformation and combine the post-electroplating technique to further increase the probe's thickness and therefore enhance its stiffness. The typical micromachined probe had a thickness of 10–25 µm, a width of 20 µm and a length of 150 µm. The maximum out-of-plane deflection of the fabricated nickel probe was approximately 55 µm. The probe's pitch can be designed to be less than 50 µm to meet the demands of fine pad pitch probing. This probe card is potentially capable of providing a very large number of micromachined probes in an array format, and this is designed also to satisfy the requirements for high resolution and low cost wafer-level testing.

A Novel Micromachined Claw Probe for the Electrical Testing of Microsolder Ball

“…4(d)]. A submicrometer-thick Ti film was then deposited by thermal evaporation as an adhesive layer and used as a seed layer because it has a large residual For the fabrication of each probe electrode, the throughsilicon via technique with inductively coupled plasma dry etching and electroplating process have been used by many studies to accomplish the interconnections embedded in the silicon substrate [14]- [16], and laser scribing has also been used to achieve the electrical separation of the electroplated Ni layer [10], in which the through-silicon via and electroplating process achieve a fine pitch and high-density multiarray interconnections with greater electrical performance and the laser machining offers great performance at low cost and a high yield. The minimum kerf width was maintained at less than 10 μm for scribing depths of 25 μm large.…”

“…Based on the complete version of Stoney's equation and the material properties of the structure layers, as well as the measured radius of curvature, the calculated residual stress of Ti film was 923 MPa [17]. A detailed report on the residual stress effect of Ti on micromachined beams is available as our previous work [10]. However, the measured radius of curvature of the deflected single-layer SiO 2 cantilever, before Ti deposition, was about 5.3 mm, and the calculated residual stress was only 8.36 MPa [18], [19].…”

“…The out-of-plane cantilever can supply enough vertical displacement to compensate for the level of deviation encountered with a large number of solder ball arrays. On the other hand, the probe with initial bending deformation can be easily fabricated by the effect of the residual stresses of using titanium (Ti) deposited on a suspended silicon dioxide (SiO 2 ) beam, as with our previous work [10]. The beam's stiffness can increase through nickel (Ni) electroplated on the curved probe.…”

Probe Array from BeCu Metal Sheet Using Heat and Fusing Currents

“…Various types of probe cards are manufactured, including epoxy, blade, vertical, array, and microspring types [1][2][3][4][5][6][7][8]. The emerging microspring microelectromechanical system (MEMS) probe card is beginning to dominate wafer testing [9][10][11][12]. These cards can achieve fine-pitch, multi-device-under-test (multi-DUT) performance and one-or minimum-touchdown wafer testing.…”

“…Hantschel et al [10] reported on connectors using stress mismatch caused by two metal beam layers. Jing et al [11] and Tsou et al [12] reported on probe tips that incorporated electroplated Ni. However, most of them are difficult to make connectors uniformly because of different stress of beam layers.…”