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.

This paper presents a micromachined claw probe with electroplating nickel for microsolder ball electrical testing applications. The suspension claw structure consists of two bridges and four curved cantilevers, which have a flexible spring constant in a small region. The out-of-plane claw-probe unit was fabricated using silicon bulk micromachining, titanium deposition, and nickel electroplating processes. The typical bending cantilever structure, made by nickel electroplating, had a thickness of 6.5 μm, a width of 10 μm, and a length of 80 μm. The maximum out-of-plane deflections of the fabricated 40 × 40 claw-probe array were approximately 50 ± 1.2 μm, under the effect of residual tensile stress of 923 MPa. For the probing test of the microsolder ball with a diameter of 200 μm, under the contact force of 1.75 mN, the measured path resistance was about 30 Ω, and the moving stroke of the microsolder ball was 14 μm. The extendable overdrive stroke was over 30 μm, after probe contact with the microsolder ball, and obvious damage was not observed on the surfaces of the claw probe except for several slight scrapes on the sidewall of the microsolder ball. This probe card is potentially capable of providing a very large number of micromachined probes in an array format and can also satisfy the requirements for a fine-pitch ball grid array and low-cost wafer-level testing.[ 2011-0299]Index Terms-Claw probe, electroplated nickel, microsolder ball, residual stresses.

Abstract-In this paper, the high density out-of-plane microprobe array is demonstrated. The fabrication processes of proposed device including bulk micromachining, thin film deposition and electroplating. By depositing the various thickness of thin film with residual tensile stress, the deflection of bending beam could be precisely controlled. The horizontal variation of bending beam array could also restrict in a few micrometer. The concept for the device fabrication is depositing the Ti thin film on a suspension SiO 2 cantilever to bring out-of-plane bending deformation, and then use electroplating process such as low stress Ni film to increase the stiffness of the probe structure without change the beam's bending profile. Through the different electroplating bath, the bending microprobe with different material, such as Ni and Cu, could be fabricated for IC testing and interconnection applications. According to the mask design, the high density probe array could easily achieve. The prototypes of the 40×40 microprobe array in pitch sizes of 50µm, 80µm and 100µm were fabricated and characterized. Measurement result by the optical interferometer shown the mean bending height of twenty samples are about 3µm, 9µm and 26µm in different beam length 25µm, 55µm and 85µm, besides the maximum horizontal variations are less than ±0.8µm, ±1.2µm, ±2µm that corresponded to the pitch size of 50µm, 80µm, and 100µm, respectively.